Thread: Stupid Question. bare with me please

Seat to cannalure.go shoot stuff.it can be as simple as that if you want it to be.

Originally Posted by Micky Duck

Seat to cannalure.go shoot stuff.it can be as simple as that if you want it to be.

And if your projectile doesn't have one??
I only use one bullet that has one and it's nowhere near in the case.

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Originally Posted by blip

Case overall length for your rifle will be determined by either your chamber or what will fit in your mag. A rough way I do it is size a case start to seat a projectile then I load it it my rifle and close the bolt on it remove round and that will give you your max chamber length, then you can see if the round fits in your mag. That's how I do it for all my rifles without special measuring gear.

This is pretty much how I do it too, although for reference this is but a functional check as I've never found a factory rifle that I've done this with where the resulting test round would fit in that rifle's magazine... Usually you have to seat to magazine depth. It's worthwhile doing this check so you know what the difference is between mag and throat length in my estimation. Doesn't really change much though?

Originally Posted by Pommy

10 thou back from being jammed into the rifling is a good way to get a pressure spike.

Why?

Factory ammo usually has a bigger jump than 10 thou? In real world as long as the developed pressure is under the limits of containment we never know about this, and in reality most often (unless it's a heavy pill or crimped) the primer gas is enough to start the pill moving towards the leade. From what I've looked at, the highest pressure situation is starting with the pill jammed into the lands or put another way there is no 'soft' movement of the bullet so the pressure curve sharply increases until the pill starts moving and being engraved by the rifling. The bigger the gap, the longer this process takes and the slower the pressure curve increases but the start of the bullet into the rifling is more abrupt - contact rifling, engraving happens and gone basically.

As noted - we usually don't notice this happening so it's purely theoretical for most of our interest here I think as long as the pressure remains under the limits of the components to contain it. If it's outside those limits then we notice it haha.

I'm saying that 10 thou is not far enough away from being jammed to aleviate the potential pressure spike from the bullet not having that run up. So we're in agreement, no?

Originally Posted by 25/08 IMP

And if your projectile doesn't have one??
I only use one bullet that has one and it's nowhere near in the case.

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Set your seating die up using whatever round you have been using. The seater will engage the olive(curvey front bit) of projectiles at a certain diameter...and will engage all similar projectiles at same diameter and thus similar length. Don't work well if switch to round most or SuperDuper long slippery pills. But if set up with the same it will seat to the same.

Originally Posted by Pommy

Needs a lot of rounds to give a good enough sample size to say with any certainty that a particular charge is giving a better ES than another. 3 rounds is not nearly enough. It probably won't make any meaningful difference. Same goes for grouping.

Agreed. What does a 3 shot group tell us about ES?


Well let's look at the ES of 15 different groups (ranging from 7-20 shots) vs the ES you get from the first 3 shots in the group. It looks like this.




The first 3 shots aren't very representative of the (more true) ES that appears with a larger sample in the majority of cases.


we can also look at a sample of 39 shots with the same rifle/load, sampled artificially as "3 shot groups" and see how representative of the true ES 3 shot groups are. It turns out that they are wildly variable; and none come close to demonstrating the "truer" ES measured across all shots.





However ES is quite a poor measure of how consistent our velocity is and how consistent we can expect it to be in future. It only takes into account the 2 most widely separated values and ignores the values of all other shots. Standard deviation is a better tool. Depending on the variability of your velocity, you should expect to get "reasonably" close to the true SD value across a sample of 10-15 rounds. Standard deviation is what should be used to assess hit probability.

4x your standard deviation (2 sigma) should be the range in which 95% of your velocities can be expected to fall. Note that I seem to have a sample size where that is currently true. I would expect 99.7% of my shots to fall within a range of 6x my SD - i.e. about 115-120fps "REAL ES". Note this is a .223 and every .223 load that I've collected sufficient data on, across several different rifles, brass, bullets and powders, loaded by different people, seems to end up with an SD around 15-20.

3 shot groups do not give you a good estimate of your SD. The standard practise of shooting 3-shot groups at different charge weights for load development and looking for a low value is invalid.

It can look like this:


You might conclude that load number 4 is the best load based on the consistent SD. There's a "node" there, right?

Wrong - every group on this chart is shot with the same load. The 3-shot SDs tell you essentially nothing.

Pressure won't be an issue if your following correct procedure and working up..... Regardless of seating depth.if your at staying load level you shouldn't get into trouble...yeah yeah if I took my nearly straight sided heavy for calibre and rammed it right down in case maybe...but normally not quite that silly

Originally Posted by Pommy

Standard twist rate for 6.5 Creedmoor is 1:8 so the 147 will be fine.

The Lyman M die is not necessary to get consistent neck tension. A standard set of reloading dies is fine.

10 thou back from being jammed into the rifling is a good way to get a pressure spike.

Needs a lot of rounds to give a good enough sample size to say with any certainty that a particular charge is giving a better ES than another. 3 rounds is not nearly enough. It probably won't make any meaningful difference. Same goes for grouping.

Adjusting seating depth is also not likely to make any noticeable difference with that bullet in a Creedmoor chamber.

Recommending that they START with what you think is a MAXIMUM load... of what is also an expensive and hard to get powder???

This is the problem with a forum.

I have been loading and developing loads for years for both competition and long range with pretty good success. I have used QL for at least 15 years. That's how I do it and never had a problem. My goal is to build the highest preforming ammo I can. I would have thought that was why we all reload.

QL is extremely good at identifying the most efficient powder for a particular cartridge and projectile. I look for a powder that fills the case to 100% burns 100% with a high efficiency. In that case RL17 was the winner. There are several other powders that come close so if cheap is what you a looking for by all means use it. That said a 6.5 Creedmore is no super long-range cartridge so maybe having your ES under 10 is not a big deal.

I'm not sure why you are all hung up on firing 5 shot groups when developing a load. It makes no sense to me at all. If you know how to read a group 3 is plenty. In my own gun I never bother with much more and nor have any other top shooters I know. That said a factory rifle more often than not will open up after 3 shots. If you are stalking with it who cares what happens after 3 shots. If you run full custom guns like me I have no doubt your experience is the same as mine, they will put 10 through the same hole. For the record I do test my finial load with a 10 shot more than anything to see when the barrel start fouling a bit.

44 was not max pressure but near to. On every single load I have developed over the years the ES settles a bit above max pressure assuming you are using the correct powder.

I get that if you have no experience with QL it seems a very foreign way to go about load development but once you understand what you are doing its an extremely reliable tool. It will predict velocities to with in 20fps or much better.

It is clear to me that you have not understood the method I was suggesting and so that is ultimately my fault as I really did need to write a book to join the dots. I am not going to bother responding to all of it as much of it has already been proven over and over not to be true.

I know my effort here is futile and I will ultimately get shouted down and that is unfortunate. This is really a hunters forum and sticking to basic loads is ultimately the best advice. It certainly keeps things safe at the expense of stifling discussion.

I will respectfully leave it at that.

Originally Posted by Taranaki Shooter

I know my effort here is futile and I will ultimately get shouted down and that is unfortunate.

Not at all. If you're willing to have a good discussion using data to try to arrive at the right answer, rather than to prove that you are right, it's more than welcome.

Originally Posted by Taranaki Shooter

This is the problem with a forum.

I have been loading and developing loads for years for both competition and long range with pretty good success. I have used QL for at least 15 years. That's how I do it and never had a problem. My goal is to build the highest preforming ammo I can. I would have thought that was why we all reload.

QL is extremely good at identifying the most efficient powder for a particular cartridge and projectile. I look for a powder that fills the case to 100% burns 100% with a high efficiency. In that case RL17 was the winner. There are several other powders that come close so if cheap is what you a looking for by all means use it. That said a 6.5 Creedmore is no super long-range cartridge so maybe having your ES under 10 is not a big deal.

I'm not sure why you are all hung up on firing 5 shot groups when developing a load. It makes no sense to me at all. If you know how to read a group 3 is plenty. In my own gun I never bother with much more and nor have any other top shooters I know. That said a factory rifle more often than not will open up after 3 shots. If you are stalking with it who cares what happens after 3 shots. If you run full custom guns like me I have no doubt your experience is the same as mine, they will put 10 through the same hole. For the record I do test my finial load with a 10 shot more than anything to see when the barrel start fouling a bit.

44 was not max pressure but near to. On every single load I have developed over the years the ES settles a bit above max pressure assuming you are using the correct powder.

I get that if you have no experience with QL it seems a very foreign way to go about load development but once you understand what you are doing its an extremely reliable tool. It will predict velocities to with in 20fps or much better.

It is clear to me that you have not understood the method I was suggesting and so that is ultimately my fault as I really did need to write a book to join the dots. I am not going to bother responding to all of it as much of it has already been proven over and over not to be true.

I know my effort here is futile and I will ultimately get shouted down and that is unfortunate. This is really a hunters forum and sticking to basic loads is ultimately the best advice. It certainly keeps things safe at the expense of stifling discussion.

I will respectfully leave it at that.

Not sure how much of that is relevant. Let's be mindful of our assumptions, eh?

Can you try and find some Reloder 17 in stock please?

Originally Posted by gimp

Agreed. What does a 3 shot group tell us about ES?


Well let's look at the ES of 15 different groups (ranging from 7-20 shots) vs the ES you get from the first 3 shots in the group. It looks like this.


Attachment 256680

The first 3 shots aren't very representative of the (more true) ES that appears with a larger sample in the majority of cases.


we can also look at a sample of 39 shots with the same rifle/load, sampled artificially as "3 shot groups" and see how representative of the true ES 3 shot groups are. It turns out that they are wildly variable; and none come close to demonstrating the "truer" ES measured across all shots.


Attachment 256678


However ES is quite a poor measure of how consistent our velocity is and how consistent we can expect it to be in future. It only takes into account the 2 most widely separated values and ignores the values of all other shots. Standard deviation is a better tool. Depending on the variability of your velocity, you should expect to get "reasonably" close to the true SD value across a sample of 10-15 rounds. Standard deviation is what should be used to assess hit probability.

4x your standard deviation should be the range in which 95% of your velocities can be expected to fall. Note that I seem to have a sample size where that is currently true. I would expect 99.7% of my shots to fall within a range of 6x my SD - i.e. about 115-120fps "REAL ES". Note this is a .223 and every .223 load that I've collected sufficient data on, across several different rifles, brass, bullets and powders, loaded by different people, seems to end up with an SD around 15-20.

3 shot groups do not give you a good estimate of your SD. The standard practise of shooting 3-shot groups at different charge weights for load development and looking for a low value is invalid.

It can look like this:
Attachment 256679

You might conclude that load number 4 is the best load based on the consistent SD. There's a "node" there, right?

Wrong - every group on this chart is shot with the same load. The 3-shot SDs tell you essentially nothing.

Not to turn this into a discussion on velocity consistency, but I'll round my thoughts off by noting that hunters shouldn't be terrible concerned about it (at all).

At ranges out to 400 metres, the hit probability difference between an SD of 10 and an SD of 30 (i.e. a "real" 95%ES of ~40 vs ~120) is essentially negligible. 100% vs 98% hit probability on a 200mm dia circle in perfect conditions.

Hunters would be far better served to prioritise their time away from the reloading bench - rather than trying to "tune" the load via methods that probably don't do anything in reality - learn to shoot from positions and read the wind. That's more likely to improve hit probability by a significant amount.

Set requirements for your load based on an understanding of hit probability, find something that meets those, then proceed to using it.

Amen to that

Totally agree with your second post Gimp. At shorter ranges I don't think ES matters too much. The caveat is so long as the variation does not interfere with barrel timing. My objection to the premise that it doesn't matter is that is is so bloody easy to fix. Why not sort it out and fix it. Even the shit Sako 308 I had here a few weeks ago got down under 15 with little effort. Disclosure I was using a full set of Redding Competition Dies bushed correctly and yes it does matter. But good powder selection and load will get you most of the way there. So why not do that?

Powder selection is critical to ES/SD yes a close powder will get you low but the right power will get you under 10.

I am currently helping a few guys with there loads and only one guy gets it. The other guys are hunters. It just needs to go bang. The guy who wants to get into it boots and all is a smart guy with deep pockets. He could careless how much it costs he just wants the same results I get. So as I was working with him and his 308 it dawned on me just how much you need to know and understand. Its a little bit intimidating at first but over the past few weeks he has wrapped his head around it and just sent me his shopping list of some very very nice gear. I weeded a few things out but its a chunk of change. Once his gun is built I know he will be a fierce competitor and he will keep me honest. I look forward to that.

My point is to come here and think I could help is a bit delusional. This is a hunters forum for hunters. Pommys recommendation to stay with handbook loads is the best advice.

What data do you have available from the process of fixing that Sako .308 ? It would be interesting to see.

I haven't worked out how to print my QL data and post it here. I think once you guys understand what I'm doing you will be find it interesting. QL is the back bone of the solution. I could not get the low ES I do with out it. Or maybe I could if I was prepared to buy 1 of each powder and test it.

The right powder will have 100% case fill and 100% burn. Using QL alone I have had crazy first test load results. Its a good tool. I'm trying to be respectful here but some of the stuff I'm reading is a bit unfortunate.

That said without QL using your powder of choice and assuming it is not too slow for the projectile you can sneak up your pressure till the ES settles down. If the powder is too slow it will go over pressure before your ES settles. If it is too fast it wont settle. your ES will be shit and stay shit. QL nails that calculation every time!! A fair amount of experience would be needed to do this safely.

My WSM posted a 3 shot ES of 1.4 and an SD of .06. Garmin Chrony, Over 15 shot preceding it was ES 6. My .284 is also ES 8 over 10 or more shots I can't remember the total now. My system works.