How much "Extreme Spread" is acceptable in competition?

[seymour fish]

This article wasnt by German was done by two other people.

Couldn’t get it to load.. any other ways to source ?

 

[fredo]

well, even after given logic, and it being refused, I want to thank you fredo...our brothers are convinced they are right
God bless em
Its a good thread and I am surprised science is rejected

So, a member suggest a google search for a primer test, in hopes I get 'learned up'.
So, I find it, and link it here, then begin reading...

Low & behold, my point of contention in this whole thread about "variables"
is substantiated, right there in the "METHOD" section of the research...

I swear, ya couldn't make this up, if ya tried!

Good shooting

 

[wesmce]

Do you have the equipment that would be required to do the test that you cited? Do you know anyone that does? We work with what we have. Some of us actually do testing. Some only opine. I would rather read about actual tests. I am always grateful for the information that is shared. It always comes at some cost to the experimenter, so their sharing it with me is very much like being handed time and money. BTW, in case you have forgotten, his goal is to determine differences in bullet velocities based on one variable, primer weight, not primer muzzle blast.[/QUOTEif you read the article I belive they talk about primer weight aswll

Couldn’t get it to load.. any other ways to source ?

 

[wesmce]

Google or search German Salazar primers should come up

 

[jim_k]

Regarding brass capacity, a poster stated that brass should be sorted by weight, so as to keep case capacity consistent. That does not work. The weight of a case has no statistically significant relationship to that case's water capacity. I did a test: First, I took 60 Lapua cases and 60 random-year Lake City Match cases. I weighed them and checked the water capacity. The bell curve on both was identical (not the same capacity, but the shape of the curve, and the extreme range was the same). Then I took 9 cases that were all right in the middle of the bell curve, and loaded them; also 9 cases, 5 from one end of the curve, and 4 from the far end of the curve. There was a difference in those cases of 0.6 or 0.7 gr capacity. Same load in both sets of cases. Same shooter, same rifle, same conditions (indoors at 100 yards). The 9-shot group of cases which all had the exact same capacity shot 0.712". The 9 cases from the extreme ends of the weight curve shot 0.706". Those were the Lake City cases.
I have not seen better results from Lapua than from Lake City, and have one 4-shot group from the Lake City batch (random years of LC Match, not sorted in any way) that is 0.022". Hornady 6.5 Creedmoor cases have a significantly larger variation in capacity, but they also shoot very well. One group of unsorted Hornady 6.5 CM cases gave a 5-shot group of 0.165" (first four shots in 0.01x"), and this was backed up by a 5-shot group measuring 0.250". Rifle was a Savage 10 FCP/McMillan, bedded with Acraglas gel, no pillars, and a diamond-lapped factory 26" chrome moly takeoff barrel set back and rechambered with the PT&G 0.199 freebore reamer. That was a test of neck turning. The turned necks gave the larger group. Again, BR shooters don't turn necks to improve accuracy, but to be confident of consistency, and to make the cases fit in custom tight-necked chambers, with a known clearance that is very small, without bullet interference on firing. On David Tubb's extreme long-range record he used necks with about 5 thousandths clearance total on both sides (2+ thou per side), but cartridge body clearance of 2 thou or slightly less (< or right at 1 thou per side). You'll have to do your own testing, but that's what I did, and that's what I've heard David Tubb say he did, to get those results.

 

[seymour fish]

Google or search German Salazar primers should come up

Thanks!

 

[seymour fish]

Regarding brass capacity, a poster stated that brass should be sorted by weight, so as to keep case capacity consistent. That does not work. The weight of a case has no statistically significant relationship to that case's water capacity. I did a test: First, I took 60 Lapua cases and 60 random-year Lake City Match cases. I weighed them and checked the water capacity. The bell curve on both was identical (not the same capacity, but the shape of the curve, and the extreme range was the same). Then I took 9 cases that were all right in the middle of the bell curve, and loaded them; also 9 cases, 5 from one end of the curve, and 4 from the far end of the curve. There was a difference in those cases of 0.6 or 0.7 gr capacity. Same load in both sets of cases. Same shooter, same rifle, same conditions (indoors at 100 yards). The 9-shot group of cases which all had the exact same capacity shot 0.712". The 9 cases from the extreme ends of the weight curve shot 0.706". Those were the Lake City cases.
I have not seen better results from Lapua than from Lake City, and have one 4-shot group from the Lake City batch (random years of LC Match, not sorted in any way) that is 0.022". Hornady 6.5 Creedmoor cases have a significantly larger variation in capacity, but they also shoot very well. One group of unsorted Hornady 6.5 CM cases gave a 5-shot group of 0.165" (first four shots in 0.01x"), and this was backed up by a 5-shot group measuring 0.250". Rifle was a Savage 10 FCP/McMillan, bedded with Acraglas gel, no pillars, and a diamond-lapped factory 26" chrome moly takeoff barrel set back and rechambered with the PT&G 0.199 freebore reamer. That was a test of neck turning. The turned necks gave the larger group. Again, BR shooters don't turn necks to improve accuracy, but to be confident of consistency, and to make the cases fit in custom tight-necked chambers, with a known clearance that is very small, without bullet interference on firing. On David Tubb's extreme long-range record he used necks with about 5 thousandths clearance total on both sides (2+ thou per side), but cartridge body clearance of 2 thou or slightly less (< or right at 1 thou per side). You'll have to do your own testing, but that's what I did, and that's what I've heard David Tubb say he did, to get those results.

Jim, have found several lots of Lapua where volume was virtually identical, and operating under the hot rod theory of equal volume chambers in the heads, just went with it. Did not delve into detecting the difference between cases of varying capacity as didn’t need to cull perfection. Perhaps threw some workable brass away based on your testing.

 

[fredo]

Regarding brass capacity, a poster stated that brass should be sorted by weight, so as to keep case capacity consistent. That does not work. The weight of a case has no statistically significant relationship to that case's water capacity. I did a test: First, I took 60 Lapua cases and 60 random-year Lake City Match cases. I weighed them and checked the water capacity. The bell curve on both was identical (not the same capacity, but the shape of the curve, and the extreme range was the same). Then I took 9 cases that were all right in the middle of the bell curve, and loaded them; also 9 cases, 5 from one end of the curve, and 4 from the far end of the curve. There was a difference in those cases of 0.6 or 0.7 gr capacity. Same load in both sets of cases. Same shooter, same rifle, same conditions (indoors at 100 yards). The 9-shot group of cases which all had the exact same capacity shot 0.712". The 9 cases from the extreme ends of the weight curve shot 0.706". Those were the Lake City cases.
I have not seen better results from Lapua than from Lake City, and have one 4-shot group from the Lake City batch (random years of LC Match, not sorted in any way) that is 0.022". Hornady 6.5 Creedmoor cases have a significantly larger variation in capacity, but they also shoot very well. One group of unsorted Hornady 6.5 CM cases gave a 5-shot group of 0.165" (first four shots in 0.01x"), and this was backed up by a 5-shot group measuring 0.250". Rifle was a Savage 10 FCP/McMillan, bedded with Acraglas gel, no pillars, and a diamond-lapped factory 26" chrome moly takeoff barrel set back and rechambered with the PT&G 0.199 freebore reamer. That was a test of neck turning. The turned necks gave the larger group. Again, BR shooters don't turn necks to improve accuracy, but to be confident of consistency, and to make the cases fit in custom tight-necked chambers, with a known clearance that is very small, without bullet interference on firing. On David Tubb's extreme long-range record he used necks with about 5 thousandths clearance total on both sides (2+ thou per side), but cartridge body clearance of 2 thou or slightly less (< or right at 1 thou per side). You'll have to do your own testing, but that's what I did, and that's what I've heard David Tubb say he did, to get those results.

Excellent info, sir.
I suggested case weight, as a means of correlating equal h2O capacity between same lot of fired cases. Afterward, realized I should've edited to make that plain. You are correct to point out that capacity should be measured & equal, for the sake of testing primers. Amongst other things...

Based on your info, there's all the more reason why a primer test SHOULD account for case variations. With the 0.6-7gr capacity delta you measured, that could easily amount to upwards of 20+ FPS muzzle velocity. But, don't take my word for it, QUCKLOAD can show ya!

There's a very good reason why scientists who conduct these studies take this sorta stuff into account. And one does not need to have tricked out lab in order to recognize sound methodology, vs. otherwise. Least, some don't...

 

[CharlieNC]

Yet, with 3 fired with light primers and 4 fired with heavy there is 99% confidence that the 26fps difference is real based on the standard deviation of those results and the "small" sample size.

 

[denobravo]

So, a member suggest a google search for a primer test, in hopes I get 'learned up'.
So, I find it, and link it here, then begin reading...

Low & behold, my point of contention in this whole thread about "variables"
is substantiated, right there in the "METHOD" section of the research...

I swear, ya couldn't make this up, if ya tried!

Good shooting

what I said

 

[dkhunt14]

Regarding brass capacity, a poster stated that brass should be sorted by weight, so as to keep case capacity consistent. That does not work. The weight of a case has no statistically significant relationship to that case's water capacity. I did a test: First, I took 60 Lapua cases and 60 random-year Lake City Match cases. I weighed them and checked the water capacity. The bell curve on both was identical (not the same capacity, but the shape of the curve, and the extreme range was the same). Then I took 9 cases that were all right in the middle of the bell curve, and loaded them; also 9 cases, 5 from one end of the curve, and 4 from the far end of the curve. There was a difference in those cases of 0.6 or 0.7 gr capacity. Same load in both sets of cases. Same shooter, same rifle, same conditions (indoors at 100 yards). The 9-shot group of cases which all had the exact same capacity shot 0.712". The 9 cases from the extreme ends of the weight curve shot 0.706". Those were the Lake City cases.
I have not seen better results from Lapua than from Lake City, and have one 4-shot group from the Lake City batch (random years of LC Match, not sorted in any way) that is 0.022". Hornady 6.5 Creedmoor cases have a significantly larger variation in capacity, but they also shoot very well. One group of unsorted Hornady 6.5 CM cases gave a 5-shot group of 0.165" (first four shots in 0.01x"), and this was backed up by a 5-shot group measuring 0.250". Rifle was a Savage 10 FCP/McMillan, bedded with Acraglas gel, no pillars, and a diamond-lapped factory 26" chrome moly takeoff barrel set back and rechambered with the PT&G 0.199 freebore reamer. That was a test of neck turning. The turned necks gave the larger group. Again, BR shooters don't turn necks to improve accuracy, but to be confident of consistency, and to make the cases fit in custom tight-necked chambers, with a known clearance that is very small, without bullet interference on firing. On David Tubb's extreme long-range record he used necks with about 5 thousandths clearance total on both sides (2+ thou per side), but cartridge body clearance of 2 thou or slightly less (< or right at 1 thou per side). You'll have to do your own testing, but that's what I did, and that's what I've heard David Tubb say he did, to get those results.

So your saying Fredo was wrong and the cases made no difference. .oo6 in group. Matt

 

[wesmce]

Do you have the equipment that would be required to do the test that you cited? Do you know anyone that does? We work with what we have. Some of us actually do testing. Some only opine. I would rather read about actual tests. I am always grateful for the information that is shared. It always comes at some cost to the experimenter, so their sharing it with me is very much like being handed time and money. BTW, in case you have forgotten, his goal is to determine differences in bullet velocities based on one variable, primer weight, not primer muzzle blast.[/QUOTEif you read the article I belive they talk about primer weight aswll

So, a member suggest a google search for a primer test, in hopes I get 'learned up'.
So, I find it, and link it here, then begin reading...

Low & behold, my point of contention in this whole thread about "variables"
is substantiated, right there in the "METHOD" section of the research...

I swear, ya couldn't make this up, if ya tried!

Good shooting

Didnt post it so you could get learned up, posted so those who would like to read and decide if any thing it had to say might be useful to them in their shooting discipline or their testing of a variable in the reloading process.The article has more to say about primers than the small section you quoted.I didnt say that any of your post were right or wrong as we probably all have our ideas about what is important to our process of getting the bullets to go where we would like them to,but one thing I have learned is to keep a open mind and read and listen to other possibilites make use of them if they are something I think might be useful.

 

[fredo]

So your saying Fredo was wrong and the cases made no difference. .oo6 in group. Matt

Boy, you're really reaching now...

How bout you refute the scientific method for us here, and for the USAF Academy scientists who conducted the study in the aforementioned link?

You can't.

And I might add that you're prolly one who's "proven" these primer tests, too...yes? Hence, the defense mechanism reply, since the science is flying in the face of your (flawed) "testing". Don't be mad at the messenger, I'm just pointing out what's been an (not so) obvious flaw. Don't worry, I don't need a "thank you"...

So, if all ya got is ad hominem personal slights, based on a single solitary instance that someone else shared? Sure sign your own argument hasn't a leg to stand on...

That established, why do you think the USAF scientists purposely sought to insulate test results from "confounding factors"?

Any idea???

 

[Alex Wheeler]

I prefer as close to perfect of a test as possible
when you leave out 2 variables and add a 3rd...it
just isnt science its guessing what cause and effect are
but you seem concrete in your position even though it is guessing
I am not going to change your mind
maybe time will

I also prefer as close to perfect as possible. In my case 200 random unsorted lapua cases were good enough to shoot a 6 and 10 match agg record at 1000 yards. If I thought there was a solid method to sort by volume I would do it, but to date I have not found a way that is accurate enough to convince me. If cases are good enough to break records they are good enough for tests relative to record size groups. Those unsorted cases routinely shot sub 2" 6 round groups in testing. These type of discussions are exactly what happens when we do more theorizing than testing. Which is why I have not gave an opinion on whether any of this matters, you need to go and test for yourself, or talk yourself out of it. Either way is fine with me

 

[fredo]

Didnt post it so you could get learned up, posted so those who would like to read and decide if any thing it had to say might be useful to them in their shooting discipline or their testing of a variable in the reloading process.The article has more to say about primers than the small section you quoted.I didnt say that any of your post were right or wrong as we probably all have our ideas about what is important to our process of getting the bullets to go where we would like them to,but one thing I have learned is to keep a open mind and read and listen to other possibilites make use of them if they are something I think might be useful.

Thank you for clarifying.
This back & forth is all about learning, so any tangible addition is always welcomed! All the more poignant that you shared a link which edifies an argument, one way or the other. I was bemused to read that it did so, mine. And to the very point, at that...

Good shooting!

 

[#40Fan]

@fredo This test isn't going to be "end all" life changing affair. Think of it just for shi*s and giggles. We got your point. Multiple times already.

You've take your dump. You can get off the pot now.

 

[fredo]

@fredo This test isn't going to be "end all" life changing affair. Think of it just for shi*s and giggles. We got your point. Multiple times already.

You've take your dump. You can get off the pot now.

Oh, I am giggling. Abit sad though, too, as I figgered there'd be more acceptance of science on here?

And again, already stated I'd never bother doing this myself. It's just the basic science background won't abide flawed testing used to push a given conclusion. So, just countering that flawed logic, with sound scientific principle...

Thanks for adding nothing of substance, other than another personal slight. I'm cool wit it, goes with the territory when truth bombs drop. It's too easy to go for the personal 'slide', than it is to argue on merit.

 

[jim_k]

So your saying Fredo was wrong and the cases made no difference. .oo6 in group. Matt

I'm telling you the test I did, and the results I got. It took a long time to do this test, and I've never heard of anyone duplicating anything statistically similar. I can say that the weight of the case does not determine that case's water capacity. Heavier cases sometimes had less internal capacity. Sometimes they had more. None of that mattered, since the "worst cases" I had grouped 0.006" better/smaller than the "best cases" I had. I hope that clarifies. You and Fredo can repeat the test, which I think would be good information. When I weighed the cases with water in them, I used an absolutely flat meniscus as my "full" determinant. Looking forward to more raw data, to validate my results (or not).

 

[BoydAllen]

Apparently Fredo thinks that playing with an internal ballistics program is as valid as results of actual tests and that he has been appointed the arbitrator of what is scientific. Test everything and if it applies, believe your targets. We test to find differences between what we think and what is is real.

This is not the first time that I have read that case weight is not a useful way to predict case capacity. Jim, Alex, and Tom, among others, do and have done a lot of actual testing. for that reason, and their successes in competition, I tend to pay a lot of attention to their posts.

 

[Falfan2017]

are all the cases the exact same? how much carbon in the neck, is this one more britol or hardened then the others, is the case capscity of these 5 the same as those...it all matters. I really can not beleive anyone would even consider arguing the point. But to each his own. Enjoy your test and thanks for your time.
I can see where this is going

Statistically speaking it may not matter. This is why you would want to shoot 40+ test shots for each instead of 5 or 10. If you shoot enough your data pool is big enough to be statistically significant. What this means is if the primers matter in a material way you will be able to draw a conclusion from your test even though you could not perfectly eliminate all variables. Think about an economic model where there are billions of variables and data points. No possible way to control all variables yet we can still make conclusions about stimulus packages, tax cuts etc.