# Firearms and Shooting > Reloading and Ballistics >  Pressure / barrel speeds?

## Gibo

Ok guys im trying to get my head around a few things. 

Firstly pressure. Why is it lighter pills in the same cal can use more of the same powder than heavier pills. Is it to do with resistance? 
How can this effect the case differently (pressure wise) ?

Secondly barrel speed?? If someone has told me my barrel is slow (tikka) how could a magnum of same cal same (tikka) go any faster? 

Just getting my head around the basics of reloading so keen to learn. Hope these even make sense: D

----------


## veitnamcam

For the same charge a lighter projectile will move more easily and build less pressure.

I think a "fast" or"slow" barrel is probably more to do with variations in chamber and how it shows pressure in the ways we normally read it..... but I really have no idea :Grin:

----------


## Gibo

> For the same charge a lighter projectile will move more easily and build less pressure.
> 
> I think a "fast" or"slow" barrel is probably more to do with variations in chamber and how it shows pressure in the ways we normally read it..... but I really have no idea


Thanks.

----------


## Pengy

Could barrel speed be purely down to twist rate ?

----------


## Banana

The lighter projectile will accelerate faster and will have moved further down the barrel when max pressure is reached.  Same pressure but more volume = more powder.

----------


## Gibo

Dont know

----------


## Gibo

> The lighter projectile will accelerate faster and will have moved further down the barrel when max pressure is reached.  Same pressure but more volume = more powder.


Mmm starting to get that bit. Thanks

----------


## veitnamcam

> Could barrel speed be purely down to twist rate ?


Slower twist should be faster as not using up as much energy to rotate mass,but the term is usually used to compare otherwise identical barrels.

----------


## Gibo

Another question. What are the common pressure signs and does anyone have photos with explanations? 
Maybe a thread from one of you gurus for us newbies to reloading?

----------


## Smiddy

> Another question. What are the common pressure signs and does anyone have photos with explanations? 
> Maybe a thread from one of you gurus for us newbies to reloading?


when you blow a primer............. you know youve hit pressure

----------


## Gibo

> when you blow a primer............. you know youve hit pressure


So i keep going till then?

----------


## Smiddy

> So i keep going till then?


jeues christ that was a joke

----------


## Toby

There was a thread somewhere with some examples. But making a new one as a sticky is a good idea.

I have a picture somewhere of ejector marks on my 6.5ai brass

----------


## Shearer

Every barrel made is different. Some tighter tolerance than others, different internal finish, due to the manufacturing process.  A 'tight', or slow barrel will grip the projectile more and therefore give lower velocities for the same pressures.

----------


## Smiddy

the first sign of pressure is usually sticky bolt lift,  this is when you feel resistance when lifting the handle to extract the round

----------


## Gibo

> jeues christ that was a joke


Ha ha got ya  :Wink:

----------


## Pengy

Haha. Probably not a good subject to joke on if you don't use emoticons  :Wink:  :Thumbsup:  :Sad:

----------


## Smiddy

another sign is the roundness of your primer after being fired,  compare it to a unfired round - it should look the same and not flat

----------


## Gibo

> the first sign of pressure is usually sticky bolt lift,  this is when you feel resistance when lifting the handle to extract the round


Cheers, i have gone .4 over max so far, started way back and still yet to length trim. Brass doesnt budge  :Have A Nice Day:

----------


## Toby

@P38 Im sure it was him who posted pics of flat and crated primers

----------


## Smiddy

other signs a stamping on the brass,  this is where the brass has "flowed" around either your ejector or maybe extractor port -  you will see it on the case head - it will be shinny

----------


## Smiddy

i usually start 1 gr below max and work up in 1gr increments untill i hit pressure then i know where it is and can back off from there in .5gr lots

----------


## Gibo

> other signs a stamping on the brass,  this is where the brass has "flowed" around either your ejector or maybe extractor port -  you will see it on the case head - it will be shinny


Seen that once or twice but happens with my mild loads now and then. Round smooth mark stamped on the head. Very lightly though snd not always??

----------


## Kiwi Greg

> Slower twist should be faster as not using up as much energy to rotate mass.


It is but by bugger, all according to Litzs new book, typically well under normal ES.

----------


## BRADS

Ok when your brass does this :Have A Nice Day: 
This wasn't my loading....it came with a gun I brought.....
Guy said they where all sweet, he seemed two no his stuff,
the first few where all fine
I really spat the dummy bolt lift was REALLY hard. I was glad it was in a Sako, a lesser action the results may have been a very different......
Lesson.....never use loads your given :Have A Nice Day: 
Let's use this as a worse case example :Have A Nice Day:

----------


## Smiddy

> Seen that once or twice but happens with my mild loads now and then. Round smooth mark stamped on the head. Very lightly though snd not always??


can be cause by brass being abit out of spec for your chamber,  if bolt lift is good and primer ok then not to worry about
its best to do your higher end loads with brass already fired in your chamber

----------


## Gibo

> another sign is the roundness of your primer after being fired,  compare it to a unfired round - it should look the same and not flat


Yip ALL primers have still had the round edges like unfired. Even the ones with a mild head mark. Are ejector marks from the hooky thing due to tightness and being hard to pull out?

----------


## Gibo

> can be cause by brass being abit out of spec for your chamber,  if bolt lift is good and primer ok then not to worry about
> its best to do your higher end loads with brass already fired in your chamber


Yip all full length sized unfired in mine is at my mild go to  :Grin:

----------


## Gibo

> Ok when your brass does this
> This wasn't my loading....it came with a gun I brought.....
> Guy said they where all sweet, he seemed two no his stuff,
> the first few where all fine
> I really spat the dummy bolt lift was REALLY hard. I was glad it was in a Sako, a lesser action the results may have been a very different......
> Lesson.....never use loads your given
> Let's use this as a worse case example


Nasty

----------


## veitnamcam

> when you blow a primer............. you know you shouldn't have bought those cheap Winchester ones off trade me


Fixed :Thumbsup:

----------


## BRADS

> Nasty


Had a beer or two after that one :Have A Nice Day:

----------


## Smiddy

> Fixed



hahaha 

federal all the way brother

----------


## Gibo

> Had a beer or two after that one


I bet. Good tip on the handloads given with sale. Pull em or chuck em  :Grin:

----------


## BRADS

> I bet. Good tip on the handloads given with sale. Pull em or chuck em


Take you don't want 90 22-250 loads?
Warmish lol :Have A Nice Day:

----------


## 257weatherby

> Ok guys im trying to get my head around a few things. 
> 
> Firstly pressure. Why is it lighter pills in the same cal can use more of the same powder than heavier pills. Is it to do with resistance? 
> How can this effect the case differently (pressure wise) ?
> 
> Secondly barrel speed?? If someone has told me my barrel is slow (tikka) how could a magnum of same cal same (tikka) go any faster? 
> 
> Just getting my head around the basics of reloading so keen to learn. Hope these even make sense: D


1-The lighter pill gives less resistance to the explosive charge trying to move it, the charge is able to expand into the increased space as the lighter projectile is driven out of it's (the gas) way faster than a heavy one - the heavier projectile has more inertia for the gas to overcome before it can drive the projectile down the bore to relieve pressure by creating space (volume), so if the heavier charge is the same as the light charge, pressure spikes faster because it has nowhere to go. When the resistance is too great, the pressure will find somewhere other than the bore to go, like back through the primer and bolt vent.

2-Two barrels from the same manufacturing run, in the same length, twist rate and calibre will not (near impossible in mass production ) be identical in bore dimension, as the projectile swages to the bore, so it is gripped and rotated, the tiniest, microscopic difference in the bore dimensions will change the resistance level to the projectile, the one with greater resistance will be the slower of the two.

----------


## veitnamcam

So in order to build a "fast barrel" one would want the minimum possible land hight and width while still managing to turn the projectile?

Sent from my GT-S5360T using Tapatalk 2

----------


## R93

No one has mentioned type of rifling or projectile bearing surface?

Sent from my SM-G900F using Tapatalk

----------


## Gibo

> No one has mentioned type of rifling or projectile bearing surface?
> 
> Sent from my SM-G900F using Tapatalk


Do tell?

----------


## BRADS

> Do tell?


Someone will no the proper answer :Have A Nice Day:  but this is my basic understanding.
Some of the longer double banded (Barnes pills?)create way more pressure than the same weight in other pills, 
Has caught a few out :Have A Nice Day:

----------


## Uplandstalker

Here's a few pictures and details of what was bad. There was some good from this one though.................. the chamber didn't explode in my face! This had very, very high pressure.

This was/still is a 223 MAX in Remington Model 700 - 60gr Partition doing 3640fps in a 1:12 twist factory barrel. The chamber has been reamed deeper to allow the extra length and powder capacity. 31.5gr of 2206H (my current safe load is 30.5gr giving 3420fps)

This photo show the ejector pin mark(the half moon or simile mark) on the side of the base. this is from when the brass flows so much that the pressure is enough to push the ejector pin back into the bolt. Sometime this can just look like a polished half circle in the base.
Also in this picture the primmer pocket has expanded so much that the primmer fell out. Lastly you can see scratches on the case; these are from the case has expanded so much that any tooling marks from the chamber reamer has allowed the brass to fill the marks and therefore mark the case very, very hard to extract. Again, this is a pretty extreme case of high pressure.  


This one shows how much of the case is out of the chamber.  This is not meant to be a belted case.

----------


## Gibo

Shit! Thanks for that

----------


## veitnamcam

Backed off half a grain and called it good?  :Grin: 

Sent from my GT-S5360T using Tapatalk 2

----------


## Happy

If given loaded rounds if you

1. Put one in the gun and bolt closed smoothly
2. Had a modded case and checked length then measured the reloads OAL
3. Had some of his used brass to visually check plus see how that went into the gun
4. Pulled one projectile and weighed the contents. Compared to the books.

After all of the above you d surely have to be ok ? And comfortable to pull the trigger on a couple of them ?
The .243 I m trying to sell for example can have to the right person 51 x brass 2 x fired plus there is 42 90 Gr Targex loads that are awesome..
To throw them away would be dumb. To reload them would be dumb. They are all set to measured length etc For me to keep them would be dumb !

If YOU were to buy this gun would you not use them ?  :Thumbsup:

----------


## BRADS

> If given loaded rounds if you
> 
> 1. Put one in the gun and bolt closed smoothly
> 2. Had a modded case and checked length then measured the reloads OAL
> 3. Had some of his used brass to visually check plus see how that went into the gun
> 4. Pulled one projectile and weighed the contents. Compared to the books.
> 
> After all of the above you d surely have to be ok ? And comfortable to pull the trigger on a couple of them ?
> The .243 I m trying to sell for example can have to the right person 51 x brass 2 x fired plus there is 42 90 Gr Targex loads that are awesome..
> ...


I wouldn't now :Have A Nice Day: 
In the past yes....my life is worth more than that two me :Have A Nice Day: 
3 grains of powder two much in a small case like a 22-250 = no fun.
Not helped buy the particular power BM2.
I did all of the above before using the reloads......but it only takes one :Have A Nice Day:

----------


## Happy

> I wouldn't now
> In the past yes....my life is worth more than that two me
> 3 grains of powder two much in a small case like a 22-250 = no fun.
> Not helped buy the particular power BM2.
> I did all of the above before using the reloads......but it only takes one


 Sorry Brads I m confused now ,,, If Im right you saying just the one was over the safety mark. Yes agree you could get caught out.


so did you pull and weigh one of the loads and it was ok within limits.. or ???  :Thumbsup: 

 Inattentive reloading could be dangerous for sure. Our machine has so far never had a fail or over beep. We check it and recheck it during the process but others may not for sure.

----------


## BRADS

> Sorry Brads I m confused now ,,, If Im right you saying just the one was over the safety mark. Yes agree you could get caught out.
> 
> 
> so did you pull and weigh one of the loads and it was ok within limits.. or ??? 
> 
>  Inattentive reloading could be dangerous for sure. Our machine has so far never had a fail or over beep. We check it and recheck it during the process but others may not for sure.


I checked 3 or 4 that where all as the should be, the one in the photo obvisiouly wasn't :Sad: 
The guy seemed very trustworthy and was a family man but people do funny shit like drinking while reloading, different powders out at once etc.

----------


## Uplandstalker

> Backed off half a grain and called it good?


That's what I did to start with, shot a deer and then the bolt still would open that easy. Just as will the stag went down straight away!

Backed off another half grain after that.

----------


## tui_man2

> Someone will no the proper answer but this is my basic understanding.
> Some of the longer double banded (Barnes pills?)create way more pressure than the same weight in other pills, 
> Has caught a few out


Other way mate likes of Barnes and gs custom projectiles with more grooves have less engraving pressure so can load higher go faster for same pressures.

Gmx have a couple in them and nosler etips have none hard projectile engraves hard and puts pressure back up.

Sent from my SM-G900F using Tapatalk

----------


## Gibo

> Other way mate likes of Barnes and gs custom projectiles with more grooves have less engraving pressure so can load higher go faster for same pressures.
> 
> Gmx have a couple in them and nosler etips have none hard projectile engraves hard and puts pressure back up.
> 
> Sent from my SM-G900F using Tapatalk


Thanks Abe that does make sense.

----------


## Nick-D

> Ok guys im trying to get my head around a few things. 
> 
> Firstly pressure. Why is it lighter pills in the same cal can use more of the same powder than heavier pills. Is it to do with resistance? 
> How can this effect the case differently (pressure wise) ?
> 
> Secondly barrel speed?? If someone has told me my barrel is slow (tikka) how could a magnum of same cal same (tikka) go any faster? 
> 
> Just getting my head around the basics of reloading so keen to learn. Hope these even make sense: D


Heavier pills = bigger pills = more surface area touching the rifleing = more friction = more pressure

----------


## Toby

Here's some ejector marks I got in my 6.5-55ai. I have lapua brass now though so will see if I can go back to that charge of powder and not get the marks



Edit: What you can't see also is loose primer pockets, Fresh primers can be put in by hand and knocked out just as easy. I did measure it but forgot how much bigger they were but it was by a bit

----------


## HNTMAD

> another sign is the roundness of your primer after being fired,  compare it to a unfired round - it should look the same and not flat


Disagree Smiddy, It should have a dent from the firing pin :Thumbsup:

----------


## Gibo

Are those marks indented toby?

----------


## Toby

Yup, not just a shine but a small gouge

----------


## R93

Trying to reach ..260 Ackley speeds eh?:p

----------


## Toby

> Trying to reach ..260 Ackley speeds eh?:p


Was on a mission to get to 3000 with 140's haha dreaming of course but got close to 2,900. I think. I can check what my top speed was if you want?

----------


## R93

I thought the 6.5 x 55 ai was faster than the .260 ai 
I get 2950 easy. 
What length barrel Toby?

----------


## Beavis

What kind of charge was that with Toby?

----------


## Toby

I'll start another thread

----------


## Gibo

> Heavier pills = bigger pills = more surface area touching the rifleing = more friction = more pressure


Mmm not sure about that, different shaped pills have different surface area. The weight is the key.

----------


## Banana

> Heavier pills = bigger pills = more surface area touching the rifleing = more friction = more pressure


Has more to do with F=ma

----------


## Uplandstalker

They are some good ejector marks!

----------


## K95

Pressure is when you kick open the bolt, the primer falls out of the oval pocket and part of your bolt is gone.


image by AckleyImproved, on Flickr


image by AckleyImproved, on Flickr

----------


## R93

> Pressure is when you kick open the bolt, the primer falls out of the oval pocket and part of your bolt is gone.
> 
> 
> image by AckleyImproved, on Flickr


Fark!!!!!

----------


## tui_man2

I fixed Willis bolt after some hot loads, out tahr shooting he smashed it up with a rock off come handle, she was all locked up hard, couldn't get bolt up had to undo the barrel to back pressure off to open bolt  :Zomg: 

Sent from my SM-G900F using Tapatalk

----------


## K95

280Ack Imp using a load I had worked up to pressure and backed off to a safe level and fired many times. It was pissing down at the time and my only guess is water got into the chamber and caused a huge pressure spike. Scared me a lot.

----------


## Nick-D

Thats not from my reloading knowledge (dont have any of that). This is just an observation based on my understanding of physics. (Civil engineer once upon a time).
 @Gibo

----------


## Gibo

> Thats not from my reloading knowledge (dont have any of that). This is just an observation based on my understanding of physics. (Civil engineer once upon a time).
>  @Gibo


All good

----------


## Nick-D

> Has more to do with F=ma


Actually, f=ma has little do do with it, other than determining 'a' as the force does not change(charge weight stays the same). The spike in pressure is cause by the increased time the projectile stays in the barrel. This increases the peak pressure as more powder is converted to gas (ie more pressure) before the projectile moves enough for the peak pressure to drop away. Much the same as a pressurised water system.

The Big determining factors on this increase in barrel time are going to be  mass or force (pill size & charge), static friction (friction build up before the prjectile moves) and of course barrel friction (givin that the projectile is slighly over bore). This is why they say do not use reloading data from 1 120 grain projectile to the next, as the frictional forces have a significant effect on initial pressure, veloctiy, and peak pressure achieved in the chamber and barrel. (as does projectile weight and charge size)

Again, no expert on ballistics, just observations based on what I remember from my engineering days

----------


## Banana

Maybe I should have written it as a=F/m.  Same force but more mass = less acceleration.  Same powder burn rate (roughly) and less projectile acceleration, so pressure peaks in less projectile travel.

----------


## hunter308

> Ok when your brass does this
> This wasn't my loading....it came with a gun I brought.....
> Guy said they where all sweet, he seemed two no his stuff,
> the first few where all fine
> I really spat the dummy bolt lift was REALLY hard. I was glad it was in a Sako, a lesser action the results may have been a very different......
> Lesson.....never use loads your given
> Let's use this as a worse case example


That definitely is a good one in the pressure department, I bought a Remington 788 in 243 a few years ago it came with some reloads from a well known ammo re-loader the shop told me who made the ammo all good with me but he never said fire at your own risk. First and second shot was sweet third shot big orange flash in my face with a big bang, bullet tumbles down range and smacks side on into target. Look at rifle smoke coming out of places it should not be coming out of along with the odor of burnt oil, go to open bolt hello it is jammed solid took it to feller who made ammo, the feller hammers bolt open, extracts case with case firmly implanted into bolt, hammers case out of bolt face primer drops on ground with a huge tit where it extruded into firing pin hole, primer pocket almost doubled in size and all case head stamping was just a bright shiny surface and all stampings gone, needless to say rifle was going to take a fair bit to fix.

----------


## Nick-D

> Maybe I should have written it as a=F/m.  Same force but more mass = less acceleration.  Same powder burn rate (roughly) and less projectile acceleration, so pressure peaks in less projectile travel.


Indeed, The burn rate will change with the pressure spike. Cant remember which way though haha. Same principles as an engine.

----------


## jakewire

lets take two bullets of the same type but different weights out of the same rifle.
say 120gr 6.5BT and 140gr 6.5BT
Correct me if I'm wrong but, say 48gr of a 2209 moves the 120gr at 2900.
But as this is well over max it would be dangerous for the 140gr
Is this because the lighter bullet has gone further down the barrel with the same powder charge so the pressure will be less than a heavier bullet that has travelled less distance therefore leaving less empty volume behind the bullet for pressure increase.
Or is that a load of bollocks and it all happens in the chamber in fraction of seconds before the bullet even gets a few mm down the barrel.
Or Something else.

----------


## Gibo

> lets take two bullets of the same type but different weights out of the same rifle.
> say 120gr 6.5BT and 140gr 6.5BT
> Correct me if I'm wrong but, say 48gr of a 2209 moves the 120gr at 2900.
> But as this is well over max it would be dangerous for the 140gr
> Is this because the lighter bullet has gone further down the barrel with the same powder charge so the pressure will be less than a heavier bullet that has travelled less distance therefore leaving less empty volume behind the bullet for pressure increase.
> Or is that a load of bollocks and it all happens in the chamber in fraction of seconds before the bullet even gets a few mm down the barrel.
> Or Something else.


Fantastic question :Grin:   i will put mine on option 1

----------


## veitnamcam

Its a compounding effect. 
the more pressure that builds the faster it burns and the more pressure builds. 
Light some powder poured on some concrete... pretty unimpressive.
Things that increase pressure but not limited to are.
increased weight 
increased neck tension
hard jackets
less jump
increased bearing surface
etc etc etc.

this is why we work up and drop back a bit and work up again if changing anything dramaticly 

Sent from my GT-S5360T using Tapatalk 2

----------


## jakewire

Yeah your right about pressure  VC, you can throw Plastic shotgun shells in an open fire and they will fizz every time.
There is absolutely no pressure there.

----------


## Nick-D

Ahh I had wondered about pressure for jump, but makes sense when going from throat to lands that there would be a pressure increase when the bullet hits the rifleing

How would you work it when playing with jump to dial in a load?

Load it close to the lands to start and start low or shift back to a lower pressure node and filddle there, then ramp back up to bigger charges once you have found a COAL/jump that your rifle likes?

----------


## veitnamcam

I usually start at max mag length or just touching the lands whichever is shorter.
ladder for pressure then load a few at steps close to max, if no joy accuracy wise start moving back.(can't go forward cos already on lands or won't fit mag)
load up some more shorter at say .5gr steps and try again.
often need more powder to get same speed after moving back.

Sent from my GT-S5360T using Tapatalk 2

----------


## Nick-D

Cool man cheers

----------


## Gibo

Ok so im going to do up some loads and find my pressure limit. Im already at .4 grains over max with no signs and no need to length size yet. May i ask how the gurus find pressure? Do I load 1x load and go up by .5 or liad 3x loads and go up slower say .3 and chrony at same time? 
Keen to know what you guys do

----------


## Gibo

No one got any advice on how to find the pressure for my rifle?

----------


## veitnamcam

the only way to find max is go over it, when you get sticky bolt lift and or case head bolt marks (with decent brass) or anything else bad you are over max ,then drop down till it just goes away and you have max.

Sent from my GT-S5360T using Tapatalk 2

----------


## Gibo

> the only way to find max is go over it, when you get sticky bolt lift and or case head bolt marks (with decent brass) or anything else bad you are over max ,then drop down till it just goes away and you have max.
> 
> Sent from my GT-S5360T using Tapatalk 2


Cheers VC
What do you go up by? And how many do you load per charge weight?

----------


## veitnamcam

half a grain should be good in 270.
one of each up from your current load.

Sent from my GT-S5360T using Tapatalk 2

----------


## Gibo

> half a grain should be good in 270.
> one of each up from your current load.
> 
> Sent from my GT-S5360T using Tapatalk 2


Sweet, im working a grain under where i have been to so far so will go from where ive been   :Grin:

----------


## 257weatherby

> Sweet, im working a grain under where i have been to so far so will go from where ive been


So what is your current powder type/gns/projectile type/weight/barrel length?

----------


## puku

> Sweet, im working a grain under where i have been to so far so will go from where ive been


Hey gibo, with the Tikka.  You will notice that your bolt lift will get quite hard when the pressure rises.
Or at least that's what I find.  I can struggle to open the bolt at times when finding max load. But there won't be a mark on case and primer is only slightly flattened

Sent from my GT-I9300 using Tapatalk

----------


## Gibo

> So what is your current powder type/gns/projectile type/weight/barrel length?


2209 51.5 grns fed 210 norma brass 21 3/4 inch barrel tikka 270 140 grn nosler ab. Been up to 52.4 grns no signs at all




> Hey gibo, with the Tikka.  You will notice that your bolt lift will get quite hard when the pressure rises.
> Or at least that's what I find.  I can struggle to open the bolt at times when finding max load. But there won't be a mark on case and primer is only slightly flattened
> 
> Sent from my GT-I9300 using Tapatalk


Cheers K, never had trouble opening the bolt yet

----------


## PerazziSC3

Im getting reasonable slap marks on my brass before i get any other signs of pressure with my tikka (norma brass)

----------


## Shearer

Remember it's winter and pressures can rise as the weather gets warmer. This will vary depending on the powder. 
I would stay away from any signs of maximum pressure at the moment. Maybe back off a full grain instead of half.

----------


## Gibo

> Remember it's winter and pressures can rise as the weather gets warmer. This will vary depending on the powder. 
> I would stay away from any signs of maximum pressure at the moment. Maybe back off a full grain instead of half.


Mmmm ive lost 40fps since summer with my happy load, is that what would be expected?

----------


## Gibo

> Im getting reasonable slap marks on my brass before i get any other signs of pressure with my tikka (norma brass)


Is a slap mark the round extractor mark on bottom of case?

----------


## PerazziSC3

> Is a slap mark the round extractor mark on bottom of case?


yep the round one is from the ejector, the squarish one is from the extractor. I get these marks well before the primers are showing signs of pressure. The bolt lift is *slightly* heavier when im getting marks on the cases.

----------


## 257weatherby

> 2209 51.5 grns fed 210 norma brass 21 3/4 inch barrel tikka 270 140 grn nosler ab. Been up to 52.4 grns no signs at all
> 
> 
> 
> Cheers K, never had trouble opening the bolt yet


Am currently working up loads for a 22" barrel .270 also, on a Weatherby Ultralight action, currently at:
-150 Berger VLD: 58x2213sc@84 fed210 2900fps 3/4" average (no pressure signs)
-140 Berger VLD: 58x2213sc@84 fed210 2900fps 5/8 average (no pressure signs)
Am going to bump the 140 VLD  up 2 grains in 1 grain increments to get to 3000fps, and try the 130 VLD Classic Hunter (top BC for a 130gn 270 proj) looking to get to 3100fps, probably the maximum sensible velocity for a 22" barrel, (especially in a 6lb rifle) not able to get the consistancy in accuracy and velocity I wanted from 2209, if 2213 hadn't worked so well I would have gone to 2217

Have tried a few others but the Bergers work so well I'll stop with them.
This rife is going on patrol in a few hours, hoping to find a resting place for a 150 VLD before oh dark tomorrow night!

----------


## Gibo

Is it just me or is the adi manual weak?

----------


## veitnamcam

Some rifles its very close and others its miles off.
It is only a guide.

Sent from my GT-S5360T using Tapatalk 2

----------


## Gibo

Car pie. I now have a good feel of things. Got a mission sorted for the end of the month. After that its experiment time  :Grin:  thanks chaps

----------


## distant stalker

In the 708 i can load to 42gr 2208 with no pressure with 162gr amaxes but 41 shows pressure with 150gr lrab. More pressure from lighter projectile of similar design (although suspect more bearing surface but too lazy to measure)

----------


## tui_man2

> In the 708 i can load to 42gr 2208 with no pressure with 162gr amaxes but 41 shows pressure with 150gr lrab. More pressure from lighter projectile of similar design (although suspect more bearing surface but too lazy to measure)


Yeah mate I'm the same in everything I have tried them in have to come back a little to. Shoot any good?

Sent from my SM-G900F using Tapatalk

----------


## distant stalker

Ok nothing amazing so far. Got a working load already though they were just a curiosity

----------


## kiwiwsniper

Hey Gibo,

My take on the Barrel speeds depends on the weight of the projectile. And this is just some food for your thoughts.

I found this is information for the .223 Remington cartridge:

Barrel Twist Rate	  1:14"	1:12"	        1:9"	        1:8"   	1:7" or 1:6.5"
Max Bullet Weight  55gr FB	65gr FB	73gr BT	80gr BT	90gr BT VLD
(from http://www.6mmbr.com/223rem.html)

1:7 twist will shoot any .223 / 5.56 bullet up to 77 grains. You can't over stabilize a bullet. If you decide to shoot very thinly jacketed bullets (typically marketed as varmint bullets) weighing less than 55 grains in a 1:7 twist bbl. keep velocity under 2800 fps to prevent tearing the jacket.
(from 223 Bullet weights for 1:7 twist - THR)

Case: Winchester Twist: 1:12" Primer: Winchester SR, Small Rifle Barrel Length: 24" Trim Length: 1.750"
55 grain projectile                                        Min    Speed        Pressure            Max   Speed     Pressure
Hodgdon	CFE 223	.224"	2.200"		26.0	3,133 	43,300 PSI		27.8	3,329	     51,300 PSI
75 grain projectile
Hodgdon	CFE 223	.224"	2.250"		23.0	2,680	        45,200 PSI		25.0	2,876	     54,400 PSI
(from Take Aim at Rifle Reloading Data | Hodgdon Reloading)

----------


## kiwiwsniper

> Mmmm ive lost 40fps since summer with my happy load, is that what would be expected?


Hey Gibo,

Did you change any batches of the components or the brands themselves? 
Remember the difference between hot air and cold air? Hot air is less dense so it should be faster.

This table is from Hodgdon powder but you might see that somethings back up your Velocity data https://www.hodgdon.com/smokeless/extreme/page3.php#top

----------


## Gibo

Only thing thats changed is the scales ha ha! From digi to balance beam. Il keep an eye on it.

----------


## veitnamcam

> Only thing thats changed is the scales ha ha! From digi to balance beam. Il keep an eye on it.


So what about the crhony ?

I have  watched my f1 clime over a hundred fps in 10 seconds as a shadow fell over it.


Sent from my GT-S5360T using Tapatalk 2

----------


## Gibo

> So what about the crhony ?
> 
> I have  watched my f1 clime over a hundred fps in 10 seconds as a shadow fell over it.
> 
> 
> Sent from my GT-S5360T using Tapatalk 2


Yeah could be, my mates loads were the same as they always are. 
Its a pro chrony, are they known for fluctuations?

----------


## kiwiwsniper

I broke my digi scales  :Pissed Off:  so I'm back on my RCBS 10:10, and after I am doing tinkering with my NEA-15 (14.5") I'm going to get another Hornady digi (might be burning a hole in my pocket from the reloaded ammo costs)

----------


## Gibo

Was using hornady digis, mate compared the digi load to the beams, digi was plys or minus .5 of a grain so they are now retired  :Have A Nice Day:

----------


## veitnamcam

> Yeah could be, my mates loads were the same as they always are. 
> Its a pro chrony, are they known for fluctuations?


yes, I bet you can't get the same average on two different days. Or even the same day if its sunny then clouds over or vice versa.

Basicy if the screens are not 4 foot apart take it with a grain of salt.
I use mine comparatively.
Shoot a known load then test load.
add or subtract speed error of known load off or on test load.

How do you know speed then?
validate at range.

Sent from my GT-S5360T using Tapatalk 2

----------


## Gibo

> yes, I bet you can't get the same average on two different days. Or even the same day if its sunny then clouds over or vice versa.
> 
> Basicy if the screens are not 4 foot apart take it with a grain of salt.
> I use mine comparatively.
> Shoot a known load then test load.
> add or subtract speed error of known load off or on test load.
> 
> How do you know speed then?
> validate at range.
> ...


Yeah really good point, i took the average from the new speeds on sunday and dropped shooter down to match. Was a tad high at 400 yards so may have to put it back to what I had. Was bang on before.

----------

