# Firearms and Shooting > Reloading and Ballistics >  Trying something,  Eric Cortina method of load development

## dannyb

So I'm trying something different.
I have been watching Eric Cortina's vids on YouTube reference "chasing the lands" and how it's a really inaccurate method of working up a load.
So for those that are un aware basically it suggests using a method that relies on an average measurement to work out distance to the lands as a reference to your seating depth may not be the best approach.
Instead he suggests seating a projectile way out in an un primed but otherwise prepped case.
Then lube up the ogive with die wax.
Put the dummy round in then close the bolt on it basically using the lands to seat the projectile.
This becomes your no go  or jam distance and in fact it is suggested you go minimum 10 thou back from this.
Then load up a charge weight ladder at your maximum length (as above jam minus 10 thou). 3 rounds at each weight.
Then shoot your ladder over a chrono to asses which charge weight gives you the most consistent fps (it may seem counter intuitive but Eric suggests not shooting these at a target, so you don't get tempted to go with a charge that shoots a fluke good group when there are more consistent speeds in your ladder).
Once you have worked out you most consistent charge weight then load up another ladder starting at your max length (jam minus 10 thou) load 3 rounds then load 3 at 3 thou deeper and do this working further away from your jam at 3 thou increments. 
The idea being that the most consistent speed load can be tuned by seating depth.
The most consistent speed is what will get you accuracy out at extended rounds.
There's a fair bit more to it than that but that's a brief run down.
In my next post I will show my progress as I try this method.
My current load development is based far more on a bit of knowledge and a fair amount of luck.
I have good brass prep, and consistent loading practices but getting my load usually expended on seating my projectile at 20 thou of the lands or as close as I could get if the mag didn't allow then just doing a ladder of charge weights to find the best grouping.
Don't get me wrong this has worked extremely well and I've achieved some brilliant results (probably a fair amount of luck rather than skill)
Anyway after watching Eric's videos they just made sense to me and a lot of it is in layman's terms.

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## dannyb

So with my model 70 270win I decided to have a crack.
Out of curiosity I measured the distance to the lands with a hornady OAL gauge and got an average length of 2.780" which would normally see me seating at 2.760 for my seating depth.
Using the Cortina method I got 2.840"
My maximum mag length allowed for a max ogive length 2.7605
So in keeping this able to be mag fed I started at 2.760"
I loaded all my charge weight ladder at this length going up in .5gn increments.
I'm using superformance for something different so started at 55.5gn through to 57.5gn
I shot them today with surprising results.



Great velocity and consistency at 56.5gn and then at 57.5gn the velocity was incredible for a 270win case but I was getting very slight ejector swipe.
I have no doubt my max load could be tuned but i don't want to be anywhere near pressure.
I am going to now load up a seating depth ladder at 56.5gn and shoot them at paper to see what accuracy is like.
It was really strange shooting the charge weight ladder over the chrono without a target but I'm really keen to see how the seating depth tunes the load.
Either way 3040fps avg is fair humming for a 145gn eldx and more than enough for a good hunting round

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## robh500

Following with interest mate. Please post results. I’ll be trying this when my labradar shows up next week.

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## dannyb

Yup need to load my seating depth ladder next and shoot them at paper.
May not have time to do that till mid next week but will see what time allows.
Will definitely post my results good or bad  :Thumbsup:

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## Micky Duck

ok bud..following you so far....now an OLD SCHOOL way of doing same....use your cleaning rod with the, object removing bit on end..eg flat end....push a projectile up the chamber and hold it as far in as it will go...may need pencil...or indeed you could just seat one only just in case and hold it in place...poke cleaning rod down from muzzle and mark rod at muzzle.remove case replace bolt,close bolt and reinsert your cleaning rod right down to bolt face,again mark...the distance between your two marks is now.............pretty darn close to your other measurement...its your maximum OVERALL length.....which in my poohseventy is no bloody use to me at all as a 130grn ballistic tip will be JUST in case mouth and no way in hell will it fit in mag....so all my rounds are made 1mm short of mag length and thats it...

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## Mooseman

Interesting results, load 56.5 seems pretty consistent, but in saying that they all were pretty good. Will be great to see how seating depth effects the accuracy.

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## dannyb

> Interesting results, load 56.5 seems pretty consistent, but in saying that they all were pretty good. Will be great to see how seating depth effects the accuracy.


I'm also wondering if seating depth will effect velocity, as the deeper I seat the pills surely pressure and velocity will increase ?
Then again maybe it will be negligible who knows ?

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## Mooseman

Yes I thought the same thing, just remember the hot temps could be a factor when you get up towards the top loads and when seating the projectiles deeper it may spike the pressure to much.

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## Micky Duck

pressure will DEFINATELY increase if you seat deeper.....take it to other extreme and you have weatherby...long freebore so case can dump pressure quickly so can have more to begin with.....by seating deeper your case capacity is less...again to extreme a 30/06 load in 308 case...

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## dannyb

> Yes I thought the same thing, just remember the hot temps could be a factor when you get up towards the top loads and when seating the projectiles deeper it may spike the pressure to much.


Yup all over it, won't be going anywhere near the hotter loads just wanted to know for reference where I started to get signs of pressure.

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## GWH

Yep seating depth has a huge effect on grouping. As far as im aware its all to do with at which stage of the barrel harmonics that the bullet is exiting the muzzle.

From the seating depth testing ive done with various rifles and loads, the difference in grouping can be considerable.

My most recent test (last week) with 65gr SGK's in a model 7 223.  I loaded several groups, starting at .005" off the lands and going to .030" in .005" steps.  All but one shot at .6-.7 moa, .015" off the lands shot .25 moa.

Id already worked out what powder charge to use from ladder tests, and some group testing at whatever coal i started at.

Clearly this particular bullet in this barrel isnt that fussy, ie .6 moa isnt too shabby, but i'll take less than half of that any day if its available just by tuning seating depth.

Ive loaded up a bunch more at that coal and charge to test further to make sure it wasn't a fluke.

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## dannyb

> Yep seating depth has a huge effect on grouping. As far as im aware its all to do with at which stage of the barrel harmonics that the bullet is exiting the muzzle.
> 
> From the seating depth testing ive done with various rifles and loads, the difference in grouping can be considerable.
> 
> My most recent test (last week) with 65gr SGK's in a model 7 223.  I loaded several groups, starting at .005" off the lands and going to .030" in .005" steps.  All but one shot at .6-.7 moa, .015" off the lands shot .25 moa.
> 
> Id already worked out what powder charge to use from ladder tests, and some group testing at whatever coal i started at.
> 
> Clearly this particular bullet in this barrel isnt that fussy, ie .6 moa isnt too shabby, but i'll take less than half of that any day if its available just by tuning seating depth.
> ...


Yup Cortina states any load can be tuned by changing seating depth and shows targets shot showing where the nodes begin, peak and taper off.
He also states that there may be multiple seating depth nodes and dome are larger than others so you need to do a comprehensive seating depth ladder to find one of these larger nodes as they will be more stable and more forgiving to tolerances created by limitations of loading gear and to an extent the skill level of the person loading.
As previously stated I'm sure a lot of this is not new or ground breaking, just the way Cortina explains it makes sense to me.
It's really very Interesting seeing the results learning how my changes influence the results and why, also understanding how to interpret what is happening especially in the seating depth ladder.

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## JaSa

The 56.5gr load looks good. Low SD, low ES but would be nice if speed would have been closer to the loads on both sides. Ideally around the 3015 or so. Might pay to load up again and get more data points? Definitely a load you would like to see how its grouping on paper and to invest time into seating depth differences.

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## ebf

@Danny, what you describe above is what I've been doing for the last 5 years. 

IT WORKS...

I use a hornady modified case & gauge to get lands measurement, but it requires some "feel" and a light touch. Helps if you repeat with several projectiles (most projectiles have pretty large variation when it comes to BTO) and average the value.

Hardest part for people to get their head around is not shooting groups during initial load dev.

Neck tension is the holy grail of accurate ammo. There are several approaches to maximize this in terms of your reloading process.

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## dannyb

> @Danny, what you describe above is what I've been doing for the last 5 years. 
> 
> IT WORKS...
> 
> 
> 
> Hardest part for people to get their head around is not shooting groups during initial load dev.


Yup quite a few people have looked at me like I've lost the plot when I tell them I shot my ladder today but didn't bother shooting it at targets  :Grin:

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## Shearer

I have tried 2 methods that sounded similar. Both were complete disasters.
The Eric Cantona method was just a kick in the face and the Ford Cortina method proved to be totally under powered. :Grin:

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## NRT

Is this boarding on OCD , 

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## dannyb

> Is this boarding on OCD , 
> 
> Sent from my TA-1025 using Tapatalk


Possibly  :Grin:

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## MMC3

Yeah, it feeds the OCD amongst us nicely. 

Interesting recent research and articles on seating depth/jump on precisionrifleblog.com too.

I often wonder about the repeatability of the “stable” velocity loads - one day I’ll retest, as I’d never pick a load based on a three-shot target, but these methods (that I’m not knocking) seem to do it on one or two rounds. 

Sometimes I do wish there was a simple answer...

Cheers, M

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## Moa Hunter

> I have tried 2 methods that sounded similar. Both were complete disasters.
> The Eric Cantona method was just a kick in the face and the Ford Cortina method proved to be totally under powered.


The Cortina method might be underpowered in your eyes, but it is a great improvement on the Morris Minor low light method that Danny and I were using

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## dannyb

> The Cortina method might be underpowered in your eyes, but it is a great improvement on the Morris Minor low light method that Danny and I were using


pretty sure I was using the Lada Niva method

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## dannyb

Well I've loaded up my first seating depth ladder
All charges at 56.5gn
3 x 2.760"
3 ×  2.757"
3 ×  2.754
3 ×  2.751"

Now I just need a day of nice settled weather to put them on paper  :Cool:

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## robh500

> Now I just need a day of nice settled weather to put them on paper


Ha ha, that’s funny, settled weather, good luck!

Keen to see results though.

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## veitnamcam

Seating depth or jump/jam is important and important  to be consistent but I really  dont see how he is doing anything different than we have all been doing for years by measuring from "jam" than "just touch".
Its the exact same thing with a different  datum point.

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## dannyb

> Seating depth or jump/jam is important and important  to be consistent but I really  dont see how he is doing anything different than we have all been doing for years by measuring from "jam" than "just touch".
> Its the exact same thing with a different  datum point.


Hey absolutely agree with you as stated earlier I don't think a lot of this is ground breaking or innovative, just the way it is explained and how the relationship of different aspects effects results and the methodical approach to finding a consistent charge weight first all just made sense to me.
I've had plenty of experts try and explain seating depth and charge weight variables to me and always ended up feeling bamboozled.
Cortina's way of explaining all this and showing results just clicked with my style of learning. We'll soon see if I can make it work, or not either way I'll post my results  :Thumbsup:

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## Moa Hunter

Cortina anticipates that the throat will be eroded over time and that distance from the lands will change. His seating depth method takes this into account and seeks to find a seating node wide enough to maintain a good consistent group over time Not just for the first 100 shots.

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## Dead is better

Ive been watching the same vids. Most enjoyed the one taking apart the eagle eye video.

Only thing i would disagree with is that some loads cant be improved. I would send anyone the bag of fmj prvi partizan i bought (if i hadn't angrily binned them). There are turds that cant be polished!

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## robh500

@dannyb out of interest mate, what chronograph are you using mate?

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## dannyb

> @dannyb out of interest mate, what chronograph are you using mate?


Caldwell ballistic precision chrono, once load development is done speed and drop are confirmed by shooting at longer ranges.
Normally I would use my magneto but it won't work with a suppressor fitted  :Oh Noes:

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## csmiffy

What are these magical chronographs you speak of?
Kidding. Used one many years ago briefly but was always factory ammo guy.
Just starting with the 243 and then the 270 and maybe the 25-303 and 264 lol

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## Pommy

It's a very clear way to approach load development.

One thing I would say when doing your seating depth test is to remember an important piece of context of his videos: he's shooting Bergers. He's also an extremely good F-Class shooter so the nut behind the butt isn't introducing much noise / human error into the equation.

The VLD's are notoriously fussy over seating depth and a few thou one way or the other is important. I think the less aggressive the ogive, the more tangent and less secant the bullet, the more forgiving on seating depth, and the more coarse you need to go in your adjustments to notice a difference.

So I'm watching with interest. My prediction is you aren't going to see a huge difference in your seating depth test, with such fine adjustments on a non-VLD bullet, and it'll be hard to spot a clear winner when factoring in any human error too.

Standing by to eat my words  :Thumbsup:

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## caberslash

Surely if you load to a standard COAL (like 2.8" on a .308) and it shoots good, call it a day?

Seen a lot of people claim their hunting rifle (Tikka/Savage/Howa whatever) is a 1/4 minute gun... not seen anyone outside of Olympic .22 being able to hold a rifle that steady (that wasn't locked in a shooting rest/vise), so how can you claim to have a rifle+ammo setup that shoots within that?

not to mention that 3 round groups mean zilch... benchrest is 5 or 10 shot groups.

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## dannyb

> Surely if you load to a standard COAL (like 2.8" on a .308) and it shoots good, call it a day?
> 
> Seen a lot of people claim their hunting rifle (Tikka/Savage/Howa whatever) is a 1/4 minute gun... not seen anyone outside of Olympic .22 being able to hold a rifle that steady (that wasn't locked in a shooting rest/vise), so how can you claim to have a rifle+ammo setup that shoots within that?
> 
> not to mention that 3 round groups mean zilch... benchrest is 5 or 10 shot groups.


You raise a valid point, I should be very clear I am no Olympic marksman this is true, but I can shoot and at 100 yards I'm confident in knowing if I have pulled a shot or not.
Your also correct 3 round groups mean zip in bench rest, however I don't shoot F class or PRS or any of that, I am just using Cortina's methods to develop a load for my hunting rifle.
If my hunting rifle shoots consistent speed and tight 3 shot groups that's plenty good enough for me.
I'm sharing my experience because the way it is explained just makes sense to me and if I can use some of his methods for developing my hunting loads and his explanations help me understand whats going on and what relationship the changes I make are showing in my groups then surely this is a good thing.

Your also right there is nothing wrong with a sammi spec load that shoots well in your rifle and if you have that great  :Thumbsup: 
I load all my own ammo so this opens up opportunities to improve or gain better accuracy so why not have a crack at it.
Plus I enjoy the challenge, I'm not out to prove anything or make massive claims, all my loads thus far for my rifles are sub moa some considerably even with 5 shot groups but you know what ? The deer don't seem to care much if I hit them an inch high or low or whatever so whilst this might seem a little OCD it's really just me playing and having a bit of fun so I won't loose too much sleep over it all.
Hopefully I'm learning too  :Grin:

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## Steelisreal

> You raise a valid point, I should be very clear I am no Olympic marksman this is true, but I can shoot and at 100 yards I'm confident in knowing if I have pulled a shot or not.
> Your also correct 3 round groups mean zip in bench rest, however I don't shoot F class or PRS or any of that, I am just using Cortina's methods to develop a load for my hunting rifle.
> If my hunting rifle shoots consistent speed and tight 3 shot groups that's plenty good enough for me.
> I'm sharing my experience because the way it is explained just makes sense to me and if I can use some of his methods for developing my hunting loads and his explanations help me understand whats going on and what relationship the changes I make are showing in my groups then surely this is a good thing.
> 
> Your also right there is nothing wrong with a sammi spec load that shoots well in your rifle and if you have that great 
> I load all my own ammo so this opens up opportunities to improve or gain better accuracy so why not have a crack at it.
> Plus I enjoy the challenge, I'm not out to prove anything or make massive claims, all my loads thus far for my rifles are sub moa some considerably even with 5 shot groups but you know what ? The deer don't seem to care much if I hit them an inch high or low or whatever so whilst this might seem a little OCD it's really just me playing and having a bit of fun so I won't loose too much sleep over it all.
> Hopefully I'm learning too


You have a good perspective on this Danny, really good to see. 

I hear far too many people saying 'close enough' or 'it's minute of deer' which is piss poor when you're taking an animals life. 

I think the most important thing you are doing is minimising one variable that you have a high level of control over. Goodness knows in a hunting situation there are so many things to get sorted to get an animal on the ground with minimal suffering. Spending time getting to know your rifle well and having confidence that you can put the right bullet in the right spot is commendable.

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## Tikka7mm08

Ahhh this is good clean fun Danny. Chase SD down to single digits then seating depth. Very close to the Berger method with VLDs that worked superbly in my 260AI. Going to chase seating depth now in my 308.

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## R93

> Ahhh this is good clean fun Danny. Chase SD down to single digits then seating depth. Very close to the Berger method with VLDs that worked superbly in my 260AI. Going to chase seating depth now in my 308.


One of the best groups I have shot with your old Ackley was with the Berger VLDs and new hydraulically formed brass with a less than perfect forming, (still had rounded shoulder) a tiny shoulder bump. Projectiles jammed into lands to ensure base is snug against bolt face. ES wasnt flash but the groups were.
Didn't worry too much about seating after that as it just shoots with acceptable ES when you do your bit it seems, wherever they're seated.
My blaser 260 ackley uses the exact same load. Also not fussy on seating. Same speed and group sizes with identical ES however the fired brass cannot be interchanged.
Shot both for the first time since before lockdown yesterday. Both shot way better than I expected as I havent fired anything but my pistols and shotgun since March. Wish I could shoot my pistols and shotguns as competently as I do my rifles after a long break. 

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## Tikka7mm08

LOL, yes my *old 260AI* and my loss... the seating method halved the groups but they were already pretty good at .6"-.7"!

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## R93

> LOL, yes my *old 260AI* and my loss... the seating method halved the groups but they were already pretty good at .6"-.7"!


Yup, it is only used as a hunting rifle so not chasing ridiculous accuracy. However it seems to easily achieve it.

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## dannyb

Well.....had an absolute mare of an afternoon at the range.
Shot my seating depth ladder but due to sucking really bad at bore sighting I only got the last 2 rounds on paper.....
I should point out I thought I was hitting the paper my eyesight ain't that flash.
All my speeds were consistent however they were about 60fps slower than the charge ladder which I can't explain.
Either way I need to load up my seating depth ladder again and maybe a few sighters as well to make sure I'm on target as today's exercise was pretty much a complete waste of time.....completely my fault   :Pissed Off:

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## dannyb

Anyone know if the Caldwell chronos are affected by different lighting ? Ie: cloudy vs clear and bright ?

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## Tikka7mm08

> Yup, it is only used as a hunting rifle so not chasing ridiculous accuracy. However it seems to easily achieve it.
> 
> Sent from my SM-T510 using Tapatalk


I don't think I could sell a rifle that wasn't acccurate!

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## zimmer

All optical chronographs can be affected by light conditions. Except maybe infra red back lit ones. 
Litz also suggests that wind can set up resonance in the sensor arms which can affect results.

As far as not getting on target I have the view that, particularly with for eg hot 7mm throat burners, that every shot fired is one shot closer to a buggered barrel so I try to minimize firing extra shots for any reason. As such, I would have used your first shots fired when doing your ES and SD testing to at least get hits on a target. Maybe EC's method of not firing anything resembling a group at the ES and SD stage is valid with kinder calibres?

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## dannyb

> All optical chronographs can be affected by light conditions. Except maybe infra red back lit ones. 
> Litz also suggests that wind can set up resonance in the sensor arms which can affect results.
> 
> As far as not getting on target I have the view that, particularly with for eg hot 7mm throat burners, that every shot fired is one shot closer to a buggered barrel so I try to minimize firing extra shots for any reason. As such, I would have used your first shots fired when doing your ES and SD testing to at least get hits on a target. Maybe EC's method of not firing anything resembling a group at the ES and SD stage is valid with kinder calibres?


Quite right, even when testing charge weights in the future I will make sure that I am at least on paper, this rifle and scope are new to me and maybe I should have put a bit more time and effort into getting it sighted first.
I have now got it pretty close to right so lesson learned and at least it's a 270win and not a WSM or big magnum.

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## R93

> Anyone know if the Caldwell chronos are affected by different lighting ? Ie: cloudy vs clear and bright ?


If they're optical, then definitely. You can borrow my radar if you meet me at Sheffield tomorrow arvo. I won't need it for a while.

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## R93

Oh.....just seen you were testing a poo 70? Might have to reneg on the offer of the radar

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## dannyb

Hopefully this will sort it. Will do a quick thread about what I have done but hopefully I can now stick to using my magnetospeed

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## chainsaw

cool, looks like you've converted your 270 to a muzzle loader.  :Thumbsup:

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## 2post

> Surely if you load to a standard COAL (like 2.8" on a .308) and it shoots good, call it a day?
> 
> Seen a lot of people claim their hunting rifle (Tikka/Savage/Howa whatever) is a 1/4 minute gun... not seen anyone outside of Olympic .22 being able to hold a rifle that steady (that wasn't locked in a shooting rest/vise), so how can you claim to have a rifle+ammo setup that shoots within that?
> 
> not to mention that 3 round groups mean zilch... benchrest is 5 or 10 shot groups.


Not many can shoot at that level but its fun trying.

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## Micky Duck

that photo looks like you trying method I suggested to find max overall length....LOL

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## Rated M for Magnum

It's very hard to argue with Eric's results. I watched his video about neck sizing vs full length sizing and thought, alright I'll give it a go. It made a bit of a difference. These are two 3 shot groups shot about a month (possibly longer) apart, from the same rifle ( Howa 1500 308), same 
type of projectiles from the same box, same powder from  the same bottle, etc.

What I'm getting at is the only difference was I full length sized the brass and the group size halved. I know 3 shots is only indicative and maybe Jupiter was fully aligned with Uranus for the second group on the left, but...I'm converted. I'll be full length sizing for this rifle from now on.

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## Tikka7mm08

I've always full length sized so your ^ results are good news!

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## Moa Hunter

Any of you guys watch Mark and Sam ?
https://www.youtube.com/watch?v=Dn1pRTvmP8k

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## Benj

> Any of you guys watch Mark and Sam ?
> https://www.youtube.com/watch?v=Dn1pRTvmP8k


I have watchEd a few of their videos, am currently trialling their cleaning regime to try and avoid a fouling shot. I’ve only tried this once - shot at a rock at 500 From a clean barrel. Height was good but was about 5 inches right, was very windy though but seems promising. Also far easier than my normal cleaning regime.

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## Rated M for Magnum

> I've always full length sized so your ^ results are good news!


I used to but I hate trimming and I usually have to after full length sizing.

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## Micky Duck

I nearly always partial length resize....BECAUSE my first rifle the mighty poohseventy.hates necksized rounds,there is suspicion chamber is slightly offcentre of bore.
full length resize and brass last 3 firings...partial length resize and 6-8 
for those who arent familiar with method..screw in full length resizer till it touches base then UNSCREW 1/2 a turn  NOT screw in more....it bumps walls of case a little and does most of neck....its in my nosler #2 manual.

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## Micky Duck

@dannyb  you havent explained the above photo yet???

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## dannyb

> @dannyb  you havent explained the above photo yet???


????

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## Micky Duck

> Hopefully this will sort it. Will do a quick thread about what I have done but hopefully I can now stick to using my magnetospeed  
> 
> Attachment 150511


WTAF are you doing????? it looks like cleaning rod in through suppressor with something attached to suppressor with tie down.....
I know there is logical explanation...just cant figure it out...

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## dannyb

> WTAF are you doing????? it looks like cleaning rod in through suppressor with something attached to suppressor with tie down.....
> I know there is logical explanation...just cant figure it out...


Tagged you in the thread that explains it bud  :Thumbsup:

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## mikee

> WTAF are you doing????? it looks like cleaning rod in through suppressor with something attached to suppressor with tie down.....
> I know there is logical explanation...just cant figure it out...


I would suspect he is checking that the first shot thru his modified magnetospeed wont make it a one shot wonder.............ie clearance check

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## dannyb

> WTAF are you doing????? it looks like cleaning rod in through suppressor with something attached to suppressor with tie down.....
> I know there is logical explanation...just cant figure it out...


It's for measuring the harmonics in my suppressor relitive to the projected flight path of the freedom seed minus the corlilas effect and the given mood on the day  :Grin:

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## Micky Duck

clear as mud now thankyou....

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## dannyb

> clear as mud now thankyou....


just modifying my magnetospeed sporter to work with a suppressor mate as I was getting inconsistent results with my mates caldwell optical chrono depending on light levels

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## Dead is better

> Seating depth or jump/jam is important and important  to be consistent but I really  dont see how he is doing anything different than we have all been doing for years by measuring from "jam" than "just touch".
> Its the exact same thing with a different  datum point.


Ironically he's just swapped one "moving target" for another. Because what is 'jam'? One case with its own neck tension and runout will never leave the bullet in the exact location as any other case on earth. 
Might as well use the 'just touch' method and take an average if you're looking to be super precise.

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## Steelisreal

> Ironically he's just swapped one "moving target" for another. Because what is 'jam'? One case with its own neck tension and runout will never leave the bullet in the exact location as any other case on earth. 
> Might as well use the 'just touch' method and take an average if you're looking to be super precise.


No, that is incorrect. For the purposes of getting started with load testing, 'jam' is the point beyond which a projectile will stick in the rifling and stay behind if a loaded round is removed from the chamber. He never references this point after an initial measurement. It is a practical safety step to avoid a problematic situation. 

The take away message of the video is not to try to measure where the lands are as this is futile (this is a moving target for sure). The whole point of the video is to show a methodology to let the target tell you what seating depth is best. By identifying the closest point to the rifling at which there is a 'tiny group node' to use as your initial length, you maximise your time shooting groups in that window. 

After you've shot a bunch of rounds you load 5 rounds at the accurate length plus 3 thousandths to see if the window of accurate lengths has moved. There is no more measuring. Shoot a group to see if the lands have moved. 

The only absolute is the base to ogive of a loaded round - this is easily measured.

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## Puffin

With the neck tension, bullets, and chamber leades where I've tried this, there has been 1mm of base-to-ogive difference in length between jammed and just touching. Backing off 20 thou (0.5mm) from jammed seems quite a large safety margin for range shooting, and would halve the available length settings I have to experiment with if wanting to keep the bullet in the lands.  At the other end I also try to avoid getting too close to the just-touching position because I've found the pressure jumps throw the ES out, and accuracy also showed day-to-day inconsistency. So my preference is to keep the bullet engaged with the rifling and then my adjustment increments are from 0.2mm engaged through to 0.7mm engaged in 0.1mm steps, so 6 steps, hoping to shoot some smaller groups somewhere within those settings. As noted in the previous posts the reference point from where I take these measurements is arbitrary provided I know roughly where the two end points (jam and touch) lie, and can just be the CBTO gauge readings. 

On a related but different topic, what are members using for their CBTO measurements please,  and how sensitive to  clamping force are the measurements if using vernier calipers,  ie does the contact surface on the gauge have a tendency to bite into the bullet jacket?

----------


## Moa Hunter

Not having a micrometer seater myself, only verniers to measure, I have sometimes used a set of feeler gauges to accurately increase seating depth from my base measurement. Is this sensible or am I making a laughing stock of myself by even mentioning it ?

----------


## Puffin

Even with a micrometer die adjustment you still have to deal with the contact point of the seating stem being some way up the ogive from where the bullet will make contact with the rifling, and the possible variation in CBTO that that could introduce. 
The Hornady gauge is inexpensive, and contacts closer to a more appropriate diameter on the bullet. 



Anyone got a homemade gauge that they can post a photo of, with details on the construction, and of course of the huge improvements in accuracy that have accrued from its usage ?

----------


## Dicko

RCBS make a calibre specific seating guage.  Bos had a .270 win one for sale here recently. The hornady system above is more flexible if you shoot multiple calibres and you can thread your own cases for a custom chamber fit (and save a few dollars). Calibre specific collars are not expensive. 

Moa there is a bit of variation in projectile length due to tip condition etc. So if you looking to make small adjustments it might not be so accurate working off total length. Working off the shoulder / contact point (ogive?) should be more accurate.

----------


## dannyb

> Moa there is a bit of variation in projectile length due to tip condition etc. So if you looking to make small adjustments it might not be so accurate working off total length. Working off the shoulder / contact point (ogive?) should be more accurate.


^^^^^^ this, definitely worth getting a comparator set for your verniers if you don't have 1, try measureing a few projectiles from your box and see how much variation there is, you may be very surprised.

----------


## Puffin

Just a note on the above, #69: threaded "modified" cases are for the OAL gauge, a measurement that M. Cortina is at pains to emphasize is not required for his method.  The stock photo I posted is misleading. Please disregard the equipment on the left that appears to be the end of the OAL gauge and a modified case, and - at the risk of stating the obvious - the process instead being that each loaded (loose) round is measured with the bullet comparator, the part clamped to the caliper jaw on the right, and then returned to the seating die as required to get the CBTO all the same for a given number of rounds that will be shot as a group.

----------


## zimmer

> ^^^^^^ this, definitely worth getting a comparator set for your verniers if you don't have 1, try measureing a few projectiles from your box and see how much variation there is, you may be very surprised.


For F Class, I, like most, batch my projectiles. Even with the better brands like Berger you can end up with 3 batches in a box of say 500. Hornady are the worst with some extreme outlyers. Although having said that my last lot of 7mm ELDMs weren't as bad as previous lots.

20 years ago Sierra used to be very bad box to box. It is the outcome of many projectile machines running in parallel with dies at various states of wear.

If you load into the lands you must check any newly acquired projectiles to avoid any surprises.

Some of the top Ozzies are also measuring the boat tails as well.

For hunting, not so important.

I have for years used the Stoney Point (now  Hornady) ogive inserts. They do a reasonable job. I also have Sinclairs version of ogive inserts. They actually give a different reading to the Hornady ones. Either the Hornady or the Sinclair contact further up the "ogive", I can't remember which way round. IIRC the Sinclair gives a truer reading. For 30 cal I have a Redback ogive insert (Australian). It is the most accurate of all. It is made out of a section of rifled barrel (unfortunately not a section of my own barrel). It is cut with the same lead angle as my barrel.

----------


## Puffin

Interested to hear of this. I had discounted the option of using a chamber reamer for a home-made bullet comparator, my thinking being that the edge of the ring of contact on a gauge should be as sharp as possible - or at least,  not of a shallow taper.  
Understood that having a leade that matches the chamber has the advantage of contacting the bullet to give the true base-to-ogive distance.  
My concern was that replicating the shallow leade angle in the gauge would make the measurement that much more subject to variation in the pressure applied by the caliper -  forcing engagement _to some extent_   with the gauge, and throwing the measurements about. 
 Any such issues ?

----------


## dannyb

Just a quick update, this is all on hold whilst I sort out a few things, I have sold my Lyman powder dispenser and will be replacing it with a RCBS chargemaster lite.
I have had a change of heart on projectile and powder choice also.
So will take me a few weeks to save some tokens and buy all the bits I need.
Basically I will start the process again and outline progress here.
I'm going to work up 150gn berger VLDH with ADI 2217 in my 270win 
And Berger 168gn VLDH and ADI 2217 in my rem mag
All this in the hope of being able to use the one powder for both.
And just cause I'm a bit of a BC slut, I just like that the Berger pills are a lot more consistent
Will be selling off some 2225 and superformance in the hope of recouping some cost towards new stuff.
Will report back here when I'm ready to start again.

----------


## zimmer

> Interested to hear of this. I had discounted the option of using a chamber reamer for a home-made bullet comparator, my thinking being that the edge of the ring of contact on a gauge should be as sharp as possible - or at least,  not of a shallow taper.  
> Understood that having a leade that matches the chamber has the advantage of contacting the bullet to give the true base-to-ogive distance.  
> My concern was that replicating the shallow leade angle in the gauge would make the measurement that much more subject to variation in the pressure applied by the caliper -  forcing engagement _to some extent_   with the gauge, and throwing the measurements about. 
>  Any such issues ?


The Redback is quite difficult to use. Sure, it is accurate but it takes a bit of jiggling around to get consistant measurements.  I won't be getting any more.

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## Moa Hunter

When I posted earlier about the feeler gauges, I should have said that I used them with my comparator inserts and calipers. As calipers are not accurate like micrometers are, I figured 3 thou of feeler gauge is a real 3 thou. So leaving the calipers fixed at one setting and measuring the increases in seat depth with feeler-gauges

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## Dicko

Measuring the desired length is one thing. Getting the same length from your seating die less the 10-20 thou etc consistently can also be a challenge.

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## dannyb

finally picked up the Winchester mod 70 today after waiting weeks for a replacement firing pin.
Will be re starting this process in the next week.
I have a box of 140gn berger VLDH
and 1 box of 140gn Nolser partitions
I may seat the partitions to sammi spec, but the Berger VLDH I will be doing the full seating depth test after finding the most consistent speed charge weight.
I also have a box of sako gamehead ammo to run through it for shits and giggles just for comparison.  :Cool:

----------


## T.FOYE

> It's very hard to argue with Eric's results. I watched his video about neck sizing vs full length sizing and thought, alright I'll give it a go. It made a bit of a difference. These are two 3 shot groups shot about a month (possibly longer) apart, from the same rifle ( Howa 1500 308), same 
> type of projectiles from the same box, same powder from  the same bottle, etc.
> 
> What I'm getting at is the only difference was I full length sized the brass and the group size halved. I know 3 shots is only indicative and maybe Jupiter was fully aligned with Uranus for the second group on the left, but...I'm converted. I'll be full length sizing for this rifle from now on. Attachment 150656


If i were examining this i would be thinking the group on the right just had slightly too much pull into the shoulder. Note how your vertical dispersion is almost identical. 
Howa 308s are like this with light projectiles flat base. Its hard to shoot em badly at 100m.

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## dannyb

Right after a bit of hiatus this is back on.
I did the jam measurements and got 2.858" with 140gn Berger VLDH
My mag in the mod 70 allows for 2.843" which just happens to be 15thou off my jam and seems like a great place to do my charge ladder.
All above measurements are ogive length not COAL.
After cleaning, annealing, prepping and priming 150 cases yesterday I'm ready for a range session.
I have 18 rounds loaded for my charge ladder, hoping to get to the range in the next day or so.

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## dannyb

I also slapped together a load for nosler 140gn partitions the other day.
Got an avg speed of 3000fps and E.S of 16fps with a load the shot just over 1" at 100 yards so I'm  pretty happy with that for a low tech non pointy drop anything on the spot load.
I've loaded up 5 more for confirmation and I'll shoot them at the range when I get a chance too.
If the partitions shoot around an inch I'll be happy as.

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## JaSa

How did 61.5, 62 and 64 group?

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## dannyb

> How did 61.5, 62 and 64 group?


Up to 63gn they all shot pretty much the same, they started to open up at 63.5gn and I started to get pressure at 64gn so settled on 63gn
Aldo anything over 63gn was compressed so I'd rather stay away from that if I can.

----------


## JaSa

Cool.
Looks like a pretty forgiving projectile to load with a big node from 61.5 -63.0gr. 63gr is a good choice in that case. Could even back down to 62.5 if you shoot within a big temperature range throughout the year.

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## dannyb

> Cool.
> Looks like a pretty forgiving projectile to load with a big node from 61.5 -63.0gr. 63gr is a good choice in that case. Could even back down to 62.5 if you shoot within a big temperature range throughout the year.


It was a pretty hot day when I shot the ladder I'm comfortable that it would be safe in any weather  :Thumbsup: 

I suspect the Bergers will ve far less forgiving, but thats ok I don't mind fiddling with them to get them shooting, I also have some of the 168gn to try in my rem mag so got a fair bit going on at the moment  :Yaeh Am Not Durnk:

----------


## Micky Duck

wow....3000fps with 140grn partition and its grouping inch.......hmmmm methinks I may just have to try some of this H1000...... thats got to put a world of hurt on any deer out to 400 yards with ease....

----------


## dannyb

> wow....3000fps with 140grn partition and its grouping inch.......hmmmm methinks I may just have to try some of this H1000...... thats got to put a world of hurt on any deer out to 400 yards with ease....


Ummmm I mean shit it's no good sprays around like a shotgun  :O O:

----------


## Micky Duck

LMFAO..... shhhh your secret safe with me...

----------


## dannyb

Ok charge weight ladder results:

61.5gn 2966, 2967, 2922

62gn 2957, 2957, 2963 

62.5gn  3030, 2976, 3012

63gn 3010, 3054, 3037

63.5gn 3059, 3051, 3052

64gn 3133, 3075, 3097 

They all shot pretty good but far the best was the hottest which shot under 1/2 inch, which was surprising considering the E.S the velocity was all over the place.
I think I'm going to try a full seating depth ladder at 62gn which gave an E.S of 6fps and shot .9 inch 3 shot group.
I was going to do a seating depth ladder at 63.5 but the problem with that is that it's already a compressed load so I don't think it's a viable option.

----------


## dannyb

What is interesting is that some of the loads with a higher E.S actually shot tighter groups, I can see why Cortina doesn't shoot is charge ladder at paper, it would be easy to be sucked into less consistent load (velocity wise).
As Cortina says group size on charge ladder is irrelevant.
Here is a pic of the best group I got today, aside from the fact it's very compressed it would be easy as a novice to look at that and go "job done"
But the E.S on that load is 58fps and who knows how erratic it might be over a larger sample this was only 3 rounds....
The load I am going to "tune" has an E.S of only 6fps which if I can get it to group better will be far more reliable when working out drops for longer shots, as it stands that load already shoots under an inch (.9") but I think I can get it better with some tuning.
Here is the half inch sucker group for reference  :Psmiley:

----------


## dannyb

Seating depth ladder all sorted....now just need the weather to play ball

----------


## Dermastor

Good on ya Danny. I am shooting charge weights and recording velocities tomorrow as I have had to change bullets for my 243 Comp rifle. Then will shoot the best ES load with reducing load lengths on Tuesday so I am hoping  to have a new load in the next few days. Erik makes a convincing argument with very little ego involved.

----------


## dannyb

> Good on ya Danny. I am shooting charge weights and recording velocities tomorrow as I have had to change bullets for my 243 Comp rifle. Then will shoot the best ES load with reducing load lengths on Tuesday so I am hoping  to have a new load in the next few days. Erik makes a convincing argument with very little ego involved.


It's been a bit of a saga getting this sorted, I desperately need a new press as the thread on my Lee where the die screws in is flogged out and allows slop.
It makes it incredibly difficult to seat with any degree of accuracy, I am literally having to hold the die steady with my left hand whilst pulling the leaver with my right.....then back the seating stem out 1/4 turn and start again with the next projectile slowly winding it back in (if I don't follow this procedure the seating depths are all over the show with no 2 the same).
Unfortunately with birthdays, wedding anniversary,  Christmas and then more birthdays funds are not likely to be directed at the lead shed till February  :Oh Noes:

----------


## Micky Duck

can you pack it with thread tape and sort of bind the bugga in place???

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## Micky Duck

also MAYBE worth a crack...can you pinch ring off 2nd set of dies and thread it on UNDERNEATH and work your two rings against each other sandwiching press in between.....the two rings pulling towards each other sort of makes the press thread redundant....

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## Micky Duck

I know when Im seating my 170grn round nose speers I have to back the die waay back up or seating stem wont go high enough to seat correctly.....so the depth of die itself isnt criticle for projectile seating.its distance from seating stem to base that matters.

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## dannyb

> also MAYBE worth a crack...can you pinch ring off 2nd set of dies and thread it on UNDERNEATH and work your two rings against each other sandwiching press in between.....the two rings pulling towards each other sort of makes the press thread redundant....


That might just work.....

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## Moa Hunter

> also MAYBE worth a crack...can you pinch ring off 2nd set of dies and thread it on UNDERNEATH and work your two rings against each other sandwiching press in between.....the two rings pulling towards each other sort of makes the press thread redundant....


Thats a cleaver idea MD. Danny I have a spare ring here that you can have, yours for the asking

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## dannyb

> Thats a cleaver idea MD. Danny I have a spare ring here that you can have, yours for the asking


Pretty sure I have a spare, but thanks for the offer I'll try it tomorrow.

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## JaSa

> What is interesting is that some of the loads with a higher E.S actually shot tighter groups,


Or the Chrono is having a bad day and you already have a real nice load but the high ES on the day leads you down the garden path  :Have A Nice Day: 

That's why lot's of data is king - and I partly disagree with Eric.
While doing a ladder test, you are already clocking up load # on the brass, using primer, burning powder, sending down lead and investing time so you may as well use the additional information of group size for your load development. Doesn't mean you trust the first good group OR the first low ES you come across but you rather go back to confirm and form a clearer picture over time on a ladder.

Bottom line for me is, I don't trust my performance on the day + I don't trust the chrono so I use repetition to filter out background noise.

----------


## dannyb

> Or the Chrono is having a bad day and you already have a real nice load but the high ES on the day leads you down the garden path 
> 
> That's why lot's of data is king - and I partly disagree with Eric.
> While doing a ladder test, you are already clocking up load # on the brass, using primer, burning powder, sending down lead and investing time so you may as well use the additional information of group size for your load development. Doesn't mean you trust the first good group OR the first low ES you come across but you rather go back to confirm and form a clearer picture over time on a ladder.
> 
> Bottom line for me is, I don't trust my performance on the day + I don't trust the chrono so I use repetition to filter out background noise.


I see where your coming from, and yes if I was just testing 1 load and not a ladder I would be inclined to agree, however all the velocities I recorded were consistent with the increase in powder which tends to suggest that the chono (magnetospeed) was not having a bad day.
Like you said lots of data and repetition filter out any misgivings, I did shoot my charge weight ladder at paper so I do have a baseline of data to work from. 
My seating depth ladder includes 3 rounds at the original seating depth of 15thou off my jam measurement just in case, this should show if the speed recorded was consistent and accurate. 
Thanks for your feedback.

----------


## dannyb

> also MAYBE worth a crack...can you pinch ring off 2nd set of dies and thread it on UNDERNEATH and work your two rings against each other sandwiching press in between.....the two rings pulling towards each other sort of makes the press thread redundant....


Well seems like it will work @Micky Duck, feels rock solid compared to without, there is enough room to get the bullet in and there is enough travel in the stem to seat them where I need to.
I'll post results next time I'm seating projectiles.

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## Micky Duck

stoked.....

----------


## Moa Hunter

> Up to 63gn they all shot pretty much the same, they started to open up at 63.5gn and I started to get pressure at 64gn so settled on 63gn
> Aldo anything over 63gn was compressed so I'd rather stay away from that if I can.


With the Partition load, I am wondering if the best charge weight might actually be at around 62.8 ish and not 63 ? Going from 63 to 63.5 'they started to open up' well 'they' might have started to open up at 63.1 or .2 on the first days tests and at 63 yesterday. Without any load tests it is just guessing. 63 might be right on the upper edge of the good spot ??

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## dannyb

> With the Partition load, I am wondering if the best charge weight might actually be at around 62.8 ish and not 63 ? Going from 63 to 63.5 'they started to open up' well 'they' might have started to open up at 63.1 or .2 on the first days tests and at 63 yesterday. Without any load tests it is just guessing. 63 might be right on the upper edge of the good spot ??


Probably need to revisit the 62gn load to be fair....I kind of fell into the speed trap and looked for the fastest best group but shit even doing 2900 fps thats plenty of hurt on reds out to plenty far. I'll get the berger load sorted then I'll come back to sort the partitions.

----------


## Dermastor

Well step one is complete. I have shot off  5 shot groups of powder development and got a result I am happy with. 107 Sierra MK in front of AR2209.

Charge weight.     Av Velocity.     ES.
40.4gr -               2862-             19
40.8gr  -              2894-             21
41.2gr -               2933-             22
41.6gr -               2975-             22
42.0gr -               3010-             11
42.4gr -               3022-            28
42.8gr -               3070-            27

I will now use 42.0gr of AR2209 with 0.003 reducing steps of loaded length and try and find the node for accuracy. Erik reckons you will find it within 0.050 of where you start. I will update you alter in the week.

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## dannyb

Shot my seating depth ladder today in much calmer conditions, this was reflected in my shooting.
All rounds were loaded at 62gn starting at my charge weight ladder length of 2.843" and working back further away from my jam in 3 thou increments. 
I shot all these rounds 1 minute apart and 5 minutes between each 3 shot group.
Anyway I'll load some pics and you can all see how it went.

First group at charge weight ladder length of 2.843" ogive 


2.840" opens up slightly 


2.837" the first shot is the higher left, the second I muffed and its low center I called it bad I had a cramp as I squeezed it off, the 3rd shot was just below the second about where I expected (I'm picking this group should have been better than the previous)
This picture should be 90degrees left with the single low shot the bottom of the group but I can't rotate it on my phone.


2.834" the best group of the lot and afte loading a few more up to verify speed this is likely were I'll settle 


2.831" starting to open up again but not much, one could argue horizontal spread could be shooter error but it felt pretty good


Pic of whole sheet just to show no fliers hidden under the calipers  :Thumbsup: 


So where I'm at now is I will load up 9 more rounds
3 at 2.836
3 at 2.834
3 at 2.832
I will shoot these over the chrono so i can collect speed data for ballistic calcs and verify stability.
Looking bloody good though.

----------


## Dicko

Danny, thats good  shooting. I get more excited about groups that show horizontal spread verse vertical like your first pic. Horizontal tends to be shooter. Vertical can be load influenced. Are you using bags or a lead sled type set up?

----------


## dannyb

> Danny, that’s good  shooting. I get more excited about groups that show horizontal spread verse vertical like your first pic. Horizontal tends to be shooter. Vertical can be load influenced. Are you using bags or a lead sled type set up?


Free standing.......just kidding bipod and a jersey rolled up under the buttstock same as how I shoot in hunting situations  :Cool:

----------


## Dicko

Nice, good to see another bloke who can shoot a decent group off hand. 
Just back tracking a bit, why 2217 in stead of the two new wonder powders RL26 or Super P?

----------


## dannyb

> Nice, good to see another bloke who can shoot a decent group off hand. 
> Just back tracking a bit, why 2217 in stead of the two new wonder powders RL26 or Super P?


A few reasons,  superformance whilst giving great results has a reputation for being temp sensitive and as I hunt all year round I wanted a temp stable powder also I have no info on if it would also work in 7mm REM MAG.
I had at first actually bought a pottle of superformance with the intent to use it but things changed.
RL26 is about as easy to buy as plutonium however if it were easier to get then I would have considered it for the same reason I went with 2217.
I went with 2217 because if I can get a accurate load worked up for both my 270 and my 7mm REM MAG than it is less different powders I have to have on hand.
Currently I load for 7mm WSM (2217), 270 WIN (2213SC for a mate), my 270 WIN (2217), 308 WIN (IMR 4895 for another mate) and currently for my 7mm  REM MAG (2225) so my powder shelf is a little like gunworks.
So I know there are several options for powder that may give better velocity for weight of charge but this was about finding a powder that would work for 2 different calibers and one was always going to be a bit of a compromise. 
Next project when this load is finalised is to work up a 168gn Berger load for my 7mm REM MAG using the 2217.
My reasoning may not be sound but it makes sense to me.

----------


## mikee

2217 is very good powder but i hope you have plenty cause it seems its now as rare as tocking horse poo too

----------


## dannyb

> 2217 is very good powder but i hope you have plenty cause it seems its now as rare as tocking horse poo too ��


Just like every other powder for that matter, 2225 is even harder to get than 2217, I am working on getting supplies of 2217  :Oh Noes:

----------


## Stocky

> Just a quick update, this is all on hold whilst I sort out a few things, I have sold my Lyman powder dispenser and will be replacing it with a RCBS chargemaster lite.
> I have had a change of heart on projectile and powder choice also.
> So will take me a few weeks to save some tokens and buy all the bits I need.
> Basically I will start the process again and outline progress here.
> I'm going to work up 150gn berger VLDH with ADI 2217 in my 270win 
> And Berger 168gn VLDH and ADI 2217 in my rem mag
> All this in the hope of being able to use the one powder for both.
> And just cause I'm a bit of a BC slut, I just like that the Berger pills are a lot more consistent
> Will be selling off some 2225 and superformance in the hope of recouping some cost towards new stuff.
> Will report back here when I'm ready to start again.


Out of interest didn't think to try the Berger 140 Classic hunters in the 270? Higher BC than the 150 VLDs and should be less temperamental to larger jump by mag length restrictions?

----------


## dannyb

> Out of interest didn't think to try the Berger 140 Classic hunters in the 270? Higher BC than the 150 VLDs and should be less temperamental to larger jump by mag length restrictions?


I'm using 140gn VLDH not using 150s I had another last minute change of heart and decided not to use 150s I'm fickle and prone to last minute decision changes  :Pacman:

----------


## Dermastor

I have completed the seating depth testing. Shooting 3 shot groups  reducing the seating depth 0.003 each time over 20 strings. I am not completely sure how to interpret the results. Yes there is definitely better and worse groups but not the definitive result I was hoping for. More groups under 0.5" would have been better. And I should have taken more time especially when the sun came out and the target was jumping sideways with the mirage. The 0.14" group was nice but the groups either side were just ho hum.

I would like to do more testing but at this stage will  load somewhere to the right of the mirage groups as there is some consistency there. If I can find some  time before the first match in Hokonui in Feb to do more work I'll let you know the results. The reality is the rifle will shoot better than me anyway.

----------


## widerange

The berger site talks of  decreasing oal in 40thou steps sometimes ending up 150thou off jam.
Take a lot of shooting to get there at 2&3 thou  increments
Some of my rifles like loads  120 or 150 off

----------


## zimmer

Below is an extract from Berger. It is aimed at VLD though. Note the first statement.
For hunting rounds the article does cover mag length elsewhere in the article. 
Pure Brian Litz. Although I have also seen him recommend, for target, 10 thou jam, then come back 20 thou (10 thou jump), then back another 20 thou and so on.


"Trying to find the COAL that puts you in the sweet spot by moving .002 to .010 will take so long the barrel may be worn out by the time you sort it out if you dont give up first. Since the sweet spot is .030 to .040 wide we recommend that you conduct the following test to find your rifles VLD sweet spot.

Load 24 rounds at the following COAL if you are a target competition shooter who does not worry about jamming a bullet:

.010 into (touching) the lands (jam) 6 rounds
.040 off the lands (jump) 6 rounds
.080 off the lands (jump) 6 rounds
.120 off the lands (jump) 6 rounds

Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event which must be avoided) or a competition shooter who worries about pulling a bullet during a match:

.010 off the lands (jump) 6 rounds
.050 off the lands (jump) 6 rounds
.090 off the lands (jump) 6 rounds
.130 off the lands (jump) 6 rounds

Shoot 2 (separate) 3 shot groups in fair conditions to see how they group. The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL towards or away from the lands .002 or .005. Taking the time to set this test up will pay off when you find that your rifle is capable of shooting the VLD bullets very well (even at 100 yards)."

----------


## Dermastor

Zimmer thanks for your input. I am starting at a mag feed length nothing to do with the lands Erik Cortina claims there will be multiple nodes and to move in 0.003 steps as a 0.010 can jump over a node.  He reckons you will find a node in 0.050 in the worst case often in  much less. It is hard to argue with a guy that has his pedigree.  I am not shooting a VLD nor off the lands. Although the results are somewhat mixed I am reasonably happy. Given I know the ES is around 11 for a 5 shot string this load work shows I will have a good result at the longer ranges out past 1000m with minimal vertical stringing. The rest will be up to me.

----------


## dannyb

> Below is an extract from Berger. It is aimed at VLD though. Note the first statement.
> For hunting rounds the article does cover mag length elsewhere in the article. 
> Pure Brian Litz. Although I have also seen him recommend, for target, 10 thou jam, then come back 20 thou (10 thou jump), then back another 20 thou and so on.
> 
> 
> "Trying to find the COAL that puts you in the sweet spot by moving .002 to .010 will take so long the barrel may be worn out by the time you sort it out if you don’t give up first. Since the sweet spot is .030 to .040 wide we recommend that you conduct the following test to find your rifles VLD sweet spot.
> 
> Load 24 rounds at the following COAL if you are a target competition shooter who does not worry about jamming a bullet:
> 
> ...


Will give that a crack with the 168s in the rem mag once I've done the velocity ladder, my 270 obviously isn't too fussy with them as they all shot pretty respectable groups.

----------


## wsm junkie

I did the Berger version with my 300wsm


I didnt fire the -130 as it was pretty obvious where things were working. Top right was comformation of -10 load and zero

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## MMC3

After watching the Erik Cortina YouTube videos and following this thread, I thought I’d give it a go.  Thanks DannyB for starting it up.  I waste far too much time and too many components on load testing, so any ‘short cut’ that works is great.  The test rifle is a Savage actioned ‘back-up’ 308 Winchester target rifle for F-TR and F-PR competition and practice.  

Specs are: 
Savage Model 16 stainless action with a Rifle Basix trigger, epoxy bedded in a Boyds laminate target-style stock. Barrel is 28” 1:10 twist stainless M24 profile (straight taper to 0.950” muzzle), made by Hugh Bradley. Chambered with a 308 Winchester tight-neck ‘Palma’ reamer by Les Grimsey. It has been showing some good accuracy potential.  Scope is a Sightron SIII 8-32x56 in Leupold rings and I’ll be using an F-TR style bipod and rear bag.

I have some Sierra 155grn ‘Palma’ projectiles that haven’t been shot in this rifle before, to use for this test.  

For the velocity test stage, my load specs are:
Lapua Small Rifle Primer 308Win brass (annealed with an AMP annealer), CCI 450 primers, Sierra 155 Palma projectiles, seated 20 thou off the lands (measured with a firm push into the lands with a Hornady seating depth gauge).

Load is 8208 powder, with four each of: 45.3, 45.5, 45.7, 45.9 and 46.1 grains (three for data, one extra in case the chronograph doesn’t register a shot).  These loads are up to a grain over the maximum of the Sierra manual.  It works for me, as the small rifle primer brass typically needs more powder to reach the same velocity/pressure as large rifle primer brass, and I’ve been shooting similar loads in this rifle with no pressure issues.  It may not work for you, so it goes without saying to stay with reloading manual loads.

I’m a fan of small steps, as I think nodes can be quite small (and easy to miss with bigger steps).

Chronograph results (with a LabRadar chronograph):
45.3 – 3002, 3009, 2991 – ES = 18 – SD = 9.1
45.5 – 3005, 3006, 3006, 3011 – ES = 7 – SD = 3.0
45.7 – 3031, 3027, 3014 – ES = 17 – SD = 8.7
45.9 – 3050, 3033, 3042 – ES = 17 – SD = 8.4
46.1 – 3064, 3041, 3058 – ES =23 – SD = 9.7

45.5 looks like the clear winner.  Given the ES of 2 after three shots, the fourth was fired and it is still very good.  The bolt had very slight resistance to lifting for the 46.1 load, so I’m happy to be 0.6grn under that.  

Forecast to rain tomorrow, so I’ll load up the length-test series, and hopefully test on Friday and report.

Any comments, questions or critique most welcome.

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## Moa Hunter

Good result with 45.5. Was that what you expected ? I am surprised that the loads either side didnt have a lower ES, putting you in the middle of a sweet spot rather than in the middle of some ordinary ES loads. 
I have had similar and dont understand it fully

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## JaSa

All nice results and I would be happy with any of them if I can tie it to a consistent good group at 500m. Shows excellent, consistent reloading procedures from you.

I recon the middle of the node will be before 45.5gr. Why? Look at the different increases of velocity per 0.2gr of powder for each group vs the ones below and above...

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## MMC3

Soooo, some results...

"Inconclusive" would be the one-word summary.  Maybe my expectations were a bit high, but I'll need to do a bit more testing.  A couple of good groups, but not yet Cortina's 'wide-node' of two consecutive small groups. In the end I did 8 different seating depths, in 0.003" increments (one was a 0.004" increment).  All were seated with a Forster press-mounted die (it seems to give me the lowest run-out) to 2.190", measured with a Hornady gauge thingy.  Then I seated to depth with a Wilson micrometer hand-die at the range, and measured each one.



I'm thinking I'll now try two steps closer to the lands (2.193 and 2.196") and repeat 2.168" and do two more steps that way (2.165 and 2.162).

 @JaSa - Yeah, I figure the velocity node is probably a bit below 45.5 given the trend.  They are loaded with an RCBS Chargemaster, so +/-0.1grains is likely happening anyway.  

 @Moa Hunter - Yup, there is much I don't understand too.  I think Litz is onto it when he says we read far too much into very small data-sets - statistically the the good groups above could be just random occurrences.

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## Tikka7mm08

Couple of cracking groups there...if either proved repeatable I'd be very happy.

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## Moa Hunter

Certainly looks like 2168 is headed / trending into a wide node. Takes a lot of time this !
One thing I would like to do myself is fire one shot every morning from a cold barrel to give a five shot group at the end of the week. A chap on youtube explained he did that when he had his final hunting load

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## distant stalker

Looks like might be worth a group at 2.165 to see if you are at longer end of that node with first group, if it gave .7 or less I'd be thinking 2.168 is in the middle and good to go (provided it is repeatable)

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## R93

> Certainly looks like 2168 is headed / trending into a wide node. Takes a lot of time this !
> One thing I would like to do myself is fire one shot every morning from a cold barrel to give a five shot group at the end of the week. A chap on youtube explained he did that when he had his final hunting load


Have done it in the past on a monthly basis and recently on a weekly basis when training or load development on other guns.

Once I worked out the wind at our local range. I managed a 5 month 1.3" group @200 yrds but didn't run it over the Chrony.
I am 4 rnds into a similar test over the radar and although the group isint quite as good (waterline) the ES so far is 6fps.
If I fire another round within say 10mins my velocity jumps 40fps and ES stays within 10-16 fps for consecutive shots.

I was interested in determining my fouled cold bore consistency as it is a hunting load. 
Apart from the 40fps jump ( has me a tiny bit confused ) when shooting consecutive shots on the cold bore I am pretty happy as the rifle never gets stretched beyond 500 yrds on game and the cold bore shot velocity hasn't so far, changed from winter to summer and that is using RL26 which is claimed to be temp sensitive.

As for the above. I can see an obvious node between 2.168 and 2.175. 



Sent from my SM-T510 using Tapatalk

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## Matt2308

> Soooo, some results...
> 
> "Inconclusive" would be the one-word summary.  Maybe my expectations were a bit high, but I'll need to do a bit more testing.  A couple of good groups, but not yet Cortina's 'wide-node' of two consecutive small groups. In the end I did 8 different seating depths, in 0.003" increments (one was a 0.004" increment).  All were seated with a Forster press-mounted die (it seems to give me the lowest run-out) to 2.190", measured with a Hornady gauge thingy.  Then I seated to depth with a Wilson micrometer hand-die at the range, and measured each one.
> 
> Attachment 157811
> 
> I'm thinking I'll now try two steps closer to the lands (2.193 and 2.196") and repeat 2.168" and do two more steps that way (2.165 and 2.162).
> 
 @JaSa - Yeah, I figure the velocity node is probably a bit below 45.5 given the trend.  They are loaded with an RCBS Chargemaster, so +/-0.1grains is likely happening anyway.  
> 
 @Moa Hunter - Yup, there is much I don't understand too.  I think Litz is onto it when he says we read far too much into very small data-sets - statistically the the good groups above could be just random occurrences.


Id say 2.165 is going to be about where you find your accuracy there. 
Should pull it in nicely.

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## distant stalker

The area circled (including the shorter length not yet tested) looks hopeful

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## MMC3

Thanks distant stalker for that extra analysis.  I will let you know how I get on with the next test batch in a few days.  
 @R93 - the cold bore first shot velocity difference and clean bore vs fouled bore velocity difference is a common phenomenon.  The long-range target stuff that I do is out to 900yds - you get two 'sighters', then (normally) 10 counting shots.  The first shot of the day is pretty much always lower vertically, usually more so for a clean bore, due to that velocity difference.

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## R93

> Thanks distant stalker for that extra analysis.  I will let you know how I get on with the next test batch in a few days.  
>  @R93 - the cold bore first shot velocity difference and clean bore vs fouled bore velocity difference is a common phenomenon.  The long-range target stuff that I do is out to 900yds - you get two 'sighters', then (normally) 10 counting shots.  The first shot of the day is pretty much always lower vertically, usually more so for a clean bore, due to that velocity difference.


I am aware of the clean bore cold shot. This barrel normally takes 3 rnds from clean to settle and hit POA. Just a bit surprised I am getting a 40fps jump after a fouled barrel cold shot.
I am assuming it is the same principle but have had excellent ES in this rifle over a 5 shot string from cold without a jump in velocity. I am a bit confused as to why it has come up now. However the cold fouled shot over the last year or so has been extremely consistent so no need to worry too much about it for a hunting rifle.

Sent from my SM-T510 using Tapatalk

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## MMC3

This time the summary is two words: pleasantly surprised.

Given the first depth-seating test series indicated a narrow node within the range and strong hints of a node at the end (longest jump-to-the-lands tested), I loaded up 3 each of:
2.193 and 2.196 (closer to the lands  approx. 0.017 and 0.014)
2.168 (repeating the good result at the end of the last test series)
2.165 and 2.162 (two steps further from the lands)

The results show:
(a) a pleasing repeatability of the 2.168 group
(b) a broad node from about 2.162 to 2.168.



Given the Cortina instructions, I should now pick 2.167 as my seating depth.

I put the chronograph back on for the last 9 and recorded an average velocity of 2995, with an ES of 19 and a SD of 5.5, so pretty happy with that.

Thanks to all for your suggestions, comments and likes.  Cheers, M

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## Tikka7mm08

Good stuff.

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## distant stalker

Nice!!!!! Looks like you have a very good load sorted

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## shooternz

> Thanks distant stalker for that extra analysis.  I will let you know how I get on with the next test batch in a few days.  
>  @R93 - the cold bore first shot velocity difference and clean bore vs fouled bore velocity difference is a common phenomenon.  The long-range target stuff that I do is out to 900yds - you get two 'sighters', then (normally) 10 counting shots.  The first shot of the day is pretty much always lower vertically, usually more so for a clean bore, due to that velocity difference.


My F class rifles clean cold bore shots are 1 MOA low for my first sighter I add ! MOA elevation and take it off for the second if your wind call is correct you get 2 keepers very handy in the F disciplines.

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## dannyb

Right finally have my new press installed and loaded up final load test and confirmation.
I loaded up 6 rounds a month ago on my old press and it was bloody diabolic trying to seat accurately.
I took those 6 rounds to the range and shot them.
The first 3 were seated at 2.834" ogive length and whilst the speed was consistent it was a bloody awful group
Which surprised me as I had already found this seating depth and charge weight to shoot very very well.
I also shot 3 at 2.831" ogive and this shot a half inch group which is what I expected from the first load.
My mate pointed out to me that when i shot the first group i was lying prone but nearly 70° to the rifle which would likely have thrown my parallax out and possibly the cause of the poor group.
So rather than suffer using my old press again I bought a new press off a forum member and waited for that to arrive before loading anymore rounds.
Fast forward 1 month.
Loaded up 3 more at 2.834" on the new press and what a delight it was to use a press that seated accurately every time.
Went to the range and put 3 factory rounds through just to check the rifle was all good and foul the barrel.
Then shot my 3 hand loaded Berger rounds.
I think I'm  done.
But I'll let the pic do the talking.





Today's fps are circled down the bottom of the list and are consistent with the last lot that I made up at the same spec as per 2 lines above.

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## dannyb

Fucked if I know why the last pic is upside down sorry guys

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## dannyb

For the doubters here's the pic of the target with nothing in the way.

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## dannyb

Hopefully fixed the upside down pic

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## Micky Duck

now write that recipe with ALL its details on the wall above press with vivid.......tis a keeper mate.....

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## dannyb

> now write that recipe with ALL its details on the wall above press with vivid.......tis a keeper mate.....


Tis in my load diary  :Thumbsup:

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## dannyb

Ballistics for anyone interested.

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## micknz

So correct me if im wrong.
Start with powder load ladder. Take the load with best ES and SD, not necessarily the best grouping on target.
Then proceed to seating depth ladder: work out jam length then ladder jam length-0.015-0.020, then 3rounds at 0.003 intervals. What are we looking at measuring with this? Just ES and SD, or target group size? 
Ive done a powder ladder, but unfortunately the best group size and best ES didnt marry up. So do i go with the best ES and see if the group size comes in with the different seating depth ladder? Or just go with the powder charge with the best grouping, and see if i can improve group size and ES with the seating depth ladder?
My powder ladder was all done with the same Coal: 0.025 off jam length

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## dannyb

> So correct me if im wrong.
> Start with powder load ladder. Take the load with best ES and SD, not necessarily the best grouping on target.
> Then proceed to seating depth ladder: work out jam length then ladder jam length-0.015-0.020, then 3rounds at 0.003 intervals. What are we looking at measuring with this? Just ES and SD, or target group size? 
> Ive done a powder ladder, but unfortunately the best group size and best ES didnt marry up. So do i go with the best ES and see if the group size comes in with the different seating depth ladder? Or just go with the powder charge with the best grouping, and see if i can improve group size and ES with the seating depth ladder?
> My powder ladder was all done with the same Coal: 0.025 off jam length


Best es, then fiddle seating depth to tune group size

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## micknz

👍Thanks. Ill be lucky to have any projectiles left after all the load development (6.5mm eld m) 🤔

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## dannyb

> 👍Thanks. Ill be lucky to have any projectiles left after all the load development (6.5mm eld m) 🤔


Sad sign of the times unfortunately,  currently developing a load for my 308 and I'm being extremely frugal just loaded to saami length and charge weight ladder, got 2 reasonable loads out of it, currently loading 3 more of each to confirm data and will pick the best and leave it at that.
As luck would have it 1 is .5" 3 shot group at 100 yards the other is .7" the chrono was playing up so only got speed of 2 rounds at each of those charge weights but looks promising at around 12-15 fps spread for both loads.
Normally I would go hard and do seating depth ladders to really tune the load but I really don't have the luxury of components and am unlikely to anytime soon like the rest of us.

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## mikee

I found this to be quite helpful
Load Development Model XLS


Makes it easier for a simple person like me to interpret results visually
From here Load Development Analysis

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## Three O'Three

I like Erics videos except the one where he criticizes neck sizing. The comments defending neck sizing were awesome and really wound up Eric.

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## Tribrit

> I like Erics videos except the one where he criticizes neck sizing. The comments defending neck sizing were awesome and really wound up Eric.


Iv been watching his videos for a while now. Listening to those F Open guys like him and F Class John and Keith Glasscock.. their anti neck sizing thing seems to come from the super super custom super tight chambers they use. Even when they say they are shooting a standard 284.. they aren't, it's all cut on a custom made reamer just for them. Hence the full length sizing so that the bolt closes.

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## rambo-6mmrem

> I like Erics videos except the one where he criticizes neck sizing. The comments defending neck sizing were awesome and really wound up Eric.


about 80% of the top shooters for fclass and or bench rest bump 1-2 thou its no more accurate then neck size and your no worse off on accuracy ether
but a 1-2 thou shoulder bump is far more reliable and consistent (you don't have to bump every 3-4 shots) as eric says he is 100% correct in those statements

for something like prs you would be stupid to neck size only
having a tight one that doesn't chamber smoothly could lose you a match

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## RugerM77

> You raise a valid point, I should be very clear I am no Olympic marksman this is true, but I can shoot and at 100 yards I'm confident in knowing if I have pulled a shot or not.
> Your also correct 3 round groups mean zip in bench rest, however I don't shoot F class or PRS or any of that, I am just using Cortina's methods to develop a load for my hunting rifle.
> If my hunting rifle shoots consistent speed and tight 3 shot groups that's plenty good enough for me.
> I'm sharing my experience because the way it is explained just makes sense to me and if I can use some of his methods for developing my hunting loads and his explanations help me understand whats going on and what relationship the changes I make are showing in my groups then surely this is a good thing.
> 
> Your also right there is nothing wrong with a sammi spec load that shoots well in your rifle and if you have that great 
> I load all my own ammo so this opens up opportunities to improve or gain better accuracy so why not have a crack at it.
> Plus I enjoy the challenge, I'm not out to prove anything or make massive claims, all my loads thus far for my rifles are sub moa some considerably even with 5 shot groups but you know what ? The deer don't seem to care much if I hit them an inch high or low or whatever so whilst this might seem a little OCD it's really just me playing and having a bit of fun so I won't loose too much sleep over it all.
> Hopefully I'm learning too


 @dannyb; Thanks for starting this mate. Learn't a heap. Much like you I don't comp shoot, just want to get the best out of my gear and it's fun. I operate under the principle that there is no such thing as a stupid question, so here goes; I've read quite a few references to SD in this thread, I'm in the dark. The only SD's I'm familiar with are sectional density and seating depth. Can anyone assist? Cheers

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## Steelisreal

> @dannyb; Thanks for starting this mate. Learn't a heap. Much like you I don't comp shoot, just want to get the best out of my gear and it's fun. I operate under the principle that there is no such thing as a stupid question, so here goes; I've read quite a few references to SD in this thread, I'm in the dark. The only SD's I'm familiar with are sectional density and seating depth. Can anyone assist? Cheers


SD = standard deviation
ES = extreme spread

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## RugerM77

Thanks mate.

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## RugerM77

Just spent a few interesting hours in the shed. I'm working with a long action Ruger M77, Shilen barrel in 7 x 57. @dannyb I see your seating depths and jam depth, in a .270. I used both the jam method and @mickyducks old school method. The curious thing, bearing in mind my calibre, with a Nosler BT 150, old school 3.188 held on lands. Jam approx 60 thou more. Tried several different brands, all had similar results. Example Rem coreloct @ 3.100 old school. I'm thinking I must have heaps of freebore, especially when I see your .270 seating depths. The good thing, though, long action magazine. Even jam measured Nosler, above, fits in mag well. Cartridge has a long neck which is going to help too. Don't know if I can manage seating adjustments in increments of 3 thou though.

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## dannyb

I now use a different method of finding jam, take a fired case and paint some loctite on the end of the projectile that goes in the case mouth, put the projectile in the case mouth making sure to leave it longer than your freebore.
Chamber the round carefully closing the bolt then leave it for 30 minutes to let the loctite set.
Carefully eject the loctite round and measure it for your jam measurement.
Works well and once you have your jam you can soak the round in hot water to release the loctited projectile.

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## RugerM77

Great idea, thanks. I was a bit concerned about the difference between jam length and projectile toucjing the lands. Interesting that Cortana says back off 15 thou from jam. Projectile definately going to be touching lands still. What's hard case is; I shoot the old Norma 150 grn soft point spire point, under minute of angle easy. Using a cleaning rod its COAL length is 3.100. I've actually got it seated at 3.130. Absolutely no pressure. So I guess the lands jam is the way to go. I've only ever used the guesometer, close enough is good enough.  I'd only accept MOA or less though. I wonder what's going to happen with a bit of science. Thanks dannyb

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## zimmer

I have used all sorts of methods - split case necks and close on long seated bullet, Stoney Point (now Hornady OAL gauge) method, Sinclairs tool for measuring seating depth (lies in cupboard unused), measure to the bolt face from muzzle with cleaning rod then push a bullet into the bore and measure from muzzle again deduct one measurement from the other. The last method is fraught with inaccuracies due to differing bullet lengths even out of the same batch. The Hornady method can give differing measurements depending on how hard you push the projectile fwd. Can sorta work OK if you take many measurements and then average the results. 

Now I just use Alex Wheeler's bolt click method only. Extremely accurate and repeatable. Also useful for tracking throat advancement.

Only thing it won't work on plunge ejector type bolts with the plunger in place. You must remove the plunger which is probably beyond the ability of the average guy. None of my rifles are plunger eject.

Just remember the measurement is only a starting point for optimum seating depth.

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## zimmer

Have a look here https://www.wheeleraccuracy.com/videos
Have a  look at "Finding your lands".
"Clickers" is similar but is dealing with tight brass.

There's some really competent guys out there, just some of them aren't always in your face.

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## RugerM77

Will do. Thanks

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## RugerM77

@zimmer had a good watch, very informative. Going to struggle with out an accurate seating die, two calibres on thier way as I speak though. This time I also watched Cortina's video. Should have done that in the first place. @dannyb case lube on the projectile makes a huge difference. Measured jam with 5 different projectiles 3 times each one. Max variation of 3 thou. Pleasantly surprised. As soon as my flash seating dies arrive I'll be into it. Rifle already shoots two loads MOA but I've got two boxes of other projectiles that shoot OK but not brilliantly. I'll try and tune them. Got pleant of 2209. Going to do the load ladder, chrono it, then back them off 20 thou from jam and work backwards. I use 760 with the two winners but I'm sure 2209 will do the job.

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## RugerM77

@dannyb. Thanks for kicking this off mate. It's a really informative read. As a consequence my whole reloading practise has changed. I was a trial and error, hit and miss guy, because I didn't know any better. Been doing that for roughly 40 years.  

Quick background; My main rifle is a M77 Mk1 long action with a Shilen barrel chambered 7 x 57. The magazine well is long enough to allow projectiles at jam length to feed.

I developed a load averaging well under minute of angle using my former method. 150 Nosler BT, 45 grn 760 @ 2550 fps. Good, but could be better. Of note, the lowest ES I could obtain with that combo, varying the load, was 21.

The current component shortage led me to googling and ringing  around provincial sports stores. I picked up Accubonds, Corelocts, 140 grn Nos BT's and N204 at old school RRP's. I already had sufficient 2209 and 760. 

The next step, obtain a Forster Micrometer Bullet seating die. That done, into action. It took a while, as spare time for me is a rare commodity.

I'll try not to bore with a lengthy diatribe and let the photo's speak. Except to say the ES was obtained by increasing loads by .3 of a grain. The seating depths were in 5 thou increments due to component shortage.

The ES was measured using 3 a shot sequence, with a fourth shot to verify if it looked promising. So all ES shown in picture was obtained with a four shot sequence.

Now for the proof of the pudding. Last Monday morning I put the method into practise. Rem Coreloct up first, starting with -5 off jam length.

Not bad, as I'd never been able to got the Corloct under minute of angle before. Of interest to me was that the load was 4 grains over ADI's stated maximum with no pressure signs. 2700 fps, quite respectable. Shots in sequence 1 minute apart, a good five minutes between groups. 3 shot groups due to component shortage. Fascinating to watch the pattern develop.

Next up Accubond, same morning.

I cheated a bit with this one, trying to save components. I hoped to pick up a tight spot quickly. That's pretty much what happened. Again, fascinating to watch it unfold in front of me.
Now I'm really hanging to try the Nos 140BT. Two really good loads so far.
A quick rider: I'll say so my self, without a hint of modesty, I have a reasonable trigger finger. 

Thanks again mate.

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## Tikka7mm08

I'd say job done with those 140gn ABs now go hunting. Some on here could have a chuckle at my comment.

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## RugerM77

@Tikka7mm08, that's something else I'm hanging to do

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## Moa Hunter

Have you watched Eric's vids on 'reading groups' ?

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## RugerM77

No, best do that, no doubt will be interesting.

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## dannyb

Reviving an old thread of mine as I'm back at it again. This time working up a load for a 30-06 ackley improved
After fire forming with some sako brass and cheap 155gn fmj, I loaded a charge ladder starting at 59gn working up to 60.5gn with 178gn eldm's seated over adi 2209.
I actually did a lower charge weight ladder starting at 57gn but I cocked up my jam measurement and it was a disaster, still the velocity of the lower charge ladder gave me confidence to start higher (without the projectile jammed hard into the lands  :Psychotic:  )
Found a good consistent velocity the higher I went with charge weight, for now I will settle at 60gn which gave an ES of 9fps and a SD of 4 fps which I thought was pretty darn good.
I have since loaded a seating depth ladder to find where the velocity node intersects with accuracy as at the seating depth I used the charge for weight ladder the accuracy was less than stellar at 1.5"-2"
My seating depth ladder starts 3 thou shorter than my charge depth ladder and continues dropping 3 thou each increment for 10 loads all at the same charge weight. I'm sure I will find accuracy somewhere I my seating depth ladder if not I'll look at doing a bedding job on it, as the rifle currently sits in a b & c stock with alloy inlet chasdis but the barrel although free floated is not bedded around the taper.
So far so good, if I can get the 60gn load down to sub moa at 2940-2950ish fps with 178 eldm's it'll be an absolute slayer and I'll be stoked


Charge ladder  veloicties



Seating depth ladder ready to shoot tomorrow all going well

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## TeRei

> @Danny, what you describe above is what I've been doing for the last 5 years. 
> 
> IT WORKS...
> 
> I use a hornady modified case & gauge to get lands measurement, but it requires some "feel" and a light touch. Helps if you repeat with several projectiles (most projectiles have pretty large variation when it comes to BTO) and average the value.
> 
> Hardest part for people to get their head around is not shooting groups during initial load dev.
> 
> Neck tension is the holy grail of accurate ammo. There are several approaches to maximize this in terms of your reloading process.


Neck tension= annealing.

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## dannyb

> Neck tension= annealing.


Yup I aneal my cases and definitely notice the neck tension feels a lot more consistent when seating

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## dannyb

Interesting afternoon at the range shot my seating depth ladder and have nailed a pretty sweet load. 
So yesterday the load that had the best ES and SD shot a less than stellar 1.8" 3 shot group, the ES was 9fps and the SD 4fps which I thought was pretty damn good and warranted further investigation even if the 1.8" 3 shot group at 100y from the charge ladder did leave me feeling a little concerned. 
I put the group out of my head and set about loading a seating depth ladder 10 steps, 3 rounds loaded at each step, 3 thou difference seating depth between steps so 30thou difference from closest to jam to furthest from jam.
I went back to the range and set about getting things set up, today I decided not to run the magnetospeed on the barrel as I wanted to make 100% sure there were no external influences that could affect the harmonics, especially as the barrel is an extremely light weight profile and fluted as well.
Immediately right from the first load (which was 3 thou shorter than the charge weight ladder groups) the groups were better, they sort of fluctuated a little then at 12 thou into my seating depth ladder they tightened right up to .8" then 15 thou .5" 18 thou saw the group back out to .7" as did the next 3 groups after that slowly increasing in size again but all sub moa.
Then at 27 thou it shot a .2" clover leaf group, the last group after that was only 2 rounds as I ran out of prepped brass but it opened back out up to 1.1".
So in conclusion I will settle on the 15 thou group that was .5" and some might ask why not the .2" seating depth and my reason is the .5" group was right in the middle of a big stable node of sub moa group producing seating depths from 12thou-27thou the last group in that node was the .2" group before it opened right out to 1.1" just 3 thou deeper so my logic is that the .2" group is right on the very edge of that accuracy node where as the .5" group is closer to my jam and has good grouping over 15 thou of tolerance so is right in the middle of that accuracy node.
Whilst this may come accross as tedious and OCD it definitely works, the other issue is that the factory trigger on this rifle is a heavy bitch and will need sorting I suspect it will be easier to shoot good groups once I've had the trigger lightened.
All in all happy to have a nice accurate load sorted. I will load up 6 or 9 confirmation loads to krono for velocity validation as I didn't krono the seating depth ladder.
End result should see 178gn eldm's at a velocity in excess of 2950fps.
I'll post pics of the charge ladder and seating ladder later this evening

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## Tahr

> Interesting afternoon at the range shot my seating depth ladder and have nailed a pretty sweet load. 
> So yesterday the load that had the best ES and SD shot a less than stellar 1.8" 3 shot group, the ES was 9fps and the SD 4fps which I thought was pretty damn good and warranted further investigation even if the 1.8" 3 shot group at 100y from the charge ladder did leave me feeling a little concerned. 
> I put the group out of my head and set about loading a seating depth ladder 10 steps, 3 rounds loaded at each step, 3 thou difference seating depth between steps so 30thou difference from closest to jam to furthest from jam.
> I went back to the range and set about getting things set up, today I decided not to run the magnetospeed on the barrel as I wanted to make 100% sure there were no external influences that could affect the harmonics, especially as the barrel is an extremely light weight profile and fluted as well.
> Immediately right from the first load (which was 3 thou shorter than the charge weight ladder groups) the groups were better, they sort of fluctuated a little then at 12 thou into my seating depth ladder they tightened right up to .8" then 15 thou .5" 18 thou saw the group back out to .7" as did the next 3 groups after that slowly increasing in size again but all sub moa.
> Then at 27 thou it shot a .2" clover leaf group, the last group after that was only 2 rounds as I ran out of prepped brass but it opened back out up to 1.1".
> So in conclusion I will settle on the 15 thou group that was .5" and some might ask why not the .2" seating depth and my reason is the .5" group was right in the middle of a big stable node of sub moa group producing seating depths from 12thou-27thou the last group in that node was the .2" group before it opened right out to 1.1" just 3 thou deeper so my logic is that the .2" group is right on the very edge of that accuracy node where as the .5" group is closer to my jam and has good grouping over 15 thou of tolerance so is right in the middle of that accuracy node.
> Whilst this may come accross as tedious and OCD it definitely works, the other issue is that the factory trigger on this rifle is a heavy bitch and will need sorting I suspect it will be easier to shoot good groups once I've had the trigger lightened.
> All in all happy to have a nice accurate load sorted. I will load up 6 or 9 confirmation loads to krono for velocity validation as I didn't krono the seating depth ladder.
> ...


Wats the rifle and history?
Pics?

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## dannyb

> Wats the rifle and history?
> Pics?


Weatherby mk v ultralight in 30-06 ackley improved,  barrel is a factory unfired 30-06 springfield that has been reamed to ackley improved.
I have swapped the trigger out with a lighter one, so hopefully I can get back to the range on Monday and verify. At suggestion ftom a mate I have loaded 5 rounds at my chosen seating depth and 5 rounds at 6 thou further into into the node just to double check.
I have also loaded up 5 extra rounds of each for krono purposes only once the load is chosen

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## Tahr

> Weatherby mk v ultralight in 30-06 ackley improved,  barrel is a factory unfired 30-06 springfield that has been reamed to ackley improved


Sounds primo. Pic?

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## chainsaw

Nice, you won’t be disappointed with the decision to go Ackley Improved.  :Thumbsup:

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## dannyb

> Sounds primo. Pic?


I'm trying but there appears to be an issue uploading pics since the forum upgrade overnight  :Oh Noes:   @DAF when i try yo upload pics i get a pop up saying  "nzhuntingandshooting.co.nz says .jpeg file upload failed"

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## dannyb

> Sounds primo. Pic?


ask and you shall recieve  :Grin: 




here is the seating depth ladder.....after tallking to my mate Jock he reckons I should also try the seating depth at .644 again as well, so I have loaded up 5 at .650 and 5 at .644 his logic was that the .644 was right in the middle of the node as opposed to the .650 which is actually closer to the front of the node.
either way which ever shoots better will be the depth settled on, I have also swapped out the trigger for one that has been fettled by a gunsmith to remove that challenge.

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## Micky Duck

looks great..a few 180grn round nose for walking in and another couple of cast lead loads with charge of trail boss up thier bum for finishing anything off or the young lasses to shoot a cheeky hare with and you will be sorted LOL...

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## chainsaw

Hard to go past that 0.638 grp.  :Thumbsup: 
The paint job of the stock looks great too.

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## dannyb

> Hard to go past that 0.638 grp. 
> The paint job of the stock looks great too.


yes at a glance, but it's right on the edge of the node, the very next seating depth just 3 thou deeper opened out to about 1.2" so I'd be more inclined to go somewhere in the middle of that node which is what I've loaded my 2 lots of confirmation loads to 1 lot at .650 and 1 lot .644 I have also swapped out the trigger for one that has been lightened and polished.

the stock finish is a matte gray over textured paint, with gold and white marble effect finsh. pretty happy with it, I also fitted a new limbasver, javelin flush cup and free floated the barrel it's come up great  :Cool:

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## Rated M for Magnum

Some very thorough testing there @dannyb that fits pretty well with the berger seating depth recommendations, I'm pretty sure theirs goes 10 thou jam, 20 thou jump, 50 thou jump, and so on in 30 thou increments. Was your node right around 15 or 20 thou jump?

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## dannyb

> Some very thorough testing there @dannyb that fits pretty well with the berger seating depth recommendations, I'm pretty sure theirs goes 10 thou jam, 20 thou jump, 50 thou jump, and so on in 30 thou increments. Was your node right around 15 or 20 thou jump?


depending on which load shoots the best of the 2 seating depths it will either be about 15 thou or 21 thou or there abouts, currently at work so can't check what I wrote down as my jam measurement

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## dannyb

Update....so i took the 2 loads i thought would be the goods to the range loaded 10x for each load which gave me 5 for a group validation and 5 for krono data.
It didn't  go well both loads had opened up shooting 1.8" and 1.5" groups and then even worse with the magnetospeed hanging off the muzzle.





Not ideal and a little frustrating  :Psychotic: 
The es and sd were still really stable so I revisited the seating depth that shot the very best group 2.638" loaded up 6 rounds 3 for group validation and 3 for krono data

Both shot extremely well again, even with the krono fitted, both 3 shot groups were under .4" I did note a slight poi shoft with the krono fitted but still a great 3 shot group.
So this load has now shot 3 sub .4" groups including the seating depth ladder. I'm gonna call that confirmed good.
The velocity was a little lower but no slouch at 2928fps avg with an sd of 9fps and an es of 18fps

Magnetospeed attached slight poi shift right


No magnetospeed


Original seating depth ladder group.



......time to load some ammo  :Cool:

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## chainsaw

good to see performance with  :Thumbsup: the 0.638 depth confirmed

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## jackson21

Depending on what sort of accuracy goal you are after? I'd recommend shooting at least 4 shot groups, preferably 5 shots to gather your initial data, 3 shot groups can be fools gold, has been for me anyway sometimes.

 I'll load 5 of each load, if after 3 clearly shit, stop on that load. If grouping in nice pattern or touching keep shooting string so you end up with 5 of potential good load verified.

You can then just pull the ones easily you don't use when get home with a cam-lock puller, recharge with load and seating depth. I have a wee RCBS partner press($190) take to range now for seating depth, can just load up a box at longest seating depth want or jam, then adjust at range to whatever plan is? Once start looking good just push more down to that depth, saves a lot of trips or seating heaps you might pull later.

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## Micky Duck

man if I had a dollar for everytime Ive heard that one...3 shots just prove rifle goes bag etc..... what a crock of poohs.
if you really want,if you really really want... to proove a load is CONSISTANT... and insist on a 5-10 shot group,shoot it 1-2 shots at a time over a month...same target,different days and conditions...but in reality Danny now has a load HE IS CONFIDENT IN...and that right there my friends is 99% of the battle won.
He KNOWS it will poke hole in animals vitals if he does his bit right....END OF LOAD DEVELOPMENT... 
write down load recipe on wall above loading bench with vivid felt pen  and stop wasting component and go fill the freezer.

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## dannyb

I have literally shot this load 9 x now, same poi , 2 of the 3 shot groups were shot 1 immediately after the other just different targets.
The only poi shift has been when i chucked the magnetospeed on the end of the barrel. You know what ? I've never needed 3 shots to drop a deer but if this rifle can stack the first 3 rounds like that every time I'm happy as, in reality what i shot today the 2 x 3 shot groups 1 after the other at different targets would be akin to a 6 shot 1/2 moa group even with the poi shift from adding the magnetospeed. But hey I'm not here to prove myself to anyone. MD your right I've gone through enough components.....I'm not blowing through anymore just to convince anyone on here. The next shots through this rifle will be at deer.

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## dannyb

Just a reminder.....this shows were i started and where I ended up...



I'm not shooting PRS or bench at 1000y guys it's an ultralight hunting rifle, either way I'm more than confident it'll put all 5 rounds in the mag where I tell it, as long as I do my bit right

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## flock

Awesome

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## dannyb

Productive afternoon, 50 make deer deader make gun go bang thingies ready to go

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## Micky Duck

when you have a spare 10 minutes..... get a blank target...place each of your shot up ones ontop of it in turn and mark your bullet holes onto the blank target...so you will end up with one target with 15-20-25 impacts marked on it...a composite group if you will....
be interesting to see just how "bad' it is......would be indicative (hows that for a wheelbarrow word before 9AM?) of a chuck it together loads preformance .

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