How much "Extreme Spread" is acceptable in competition?

[Rustytigwire]

Wear a glove, depriming is one if bigger sources of lead expose in reloading.

Peanut gallery here, this is a great discussion!
So many variables, which ones to improve.
I watched a friend shoot my AR last week. My technique is in need of discipline for sure.
Shawn, im a hands on guy. Thanks for the lead reminder. You made a difference today!

 

[fredo]

So, tell us of your properly done test, and the results. Your post seems more than a bit vague. Saying that something is obvious hardly qualifies as a proper challenge of a procedure. I think that the test of the validity of results is whether they are reproducible, using the exact same procedure.

You have offered exactly no proof of your assertion of the faults in his method. You only say that they are obvious.

Proof?
Ok, ask yourself this...

Do BR accuracy nuts, as a matter of standard procedure, use the same lot of (standardized/fully prepped) brass for their match loads?

If the answer is NO, I'll address your contentions.

BUT...if the answer is YES, then you just addressed mine...

Think about it.

Why does brass consistency matter so much while seeking the smallest group? Yet, the same consistency, which I prefaced my argument upon, is so easily cast aside as irrelevant???

I'll wait...

 

[CharlieNC]

Overkill gentleman, since already with a few shots a very significant difference was already found. Meaning the signal is much larger than the noise you are worried about. Or put another way the current results mean if you want to evaluate say the effect of brass weight, you must weigh the primers to assure they are all identical so as not to confuse the results. Of course at some stage when it is desired to quantify minute effects, such painstaking labor might be necessary. But the OP already has found a major impact via preliminary screening.

 

[fredo]

Charlie, respectfully...

How can one attribute results to that of a primer, when the internal volume of the vessel (the case itself) has not been 'standardized?

Likewise, how can data be analyzed about the primer, when resultant pressure from an explosion in said vessel, is subject to varying neck tension?

With those questions un-answered, how can one differentiate the 'data' from the "noise"???

 

[BoydAllen]

I have some experience shooting in sanctioned short range benchrest matches, loading between matches, using a set of cases all weekend. I have also done testing reloading a single case testing, loading at the range. From that experience I have observed some case to case variation in seating force, that was not present when I took the time to use a single case. Have you done these things? Because they have much less mechanical advantage, arbor presses make it a lot easier to feel differences in seating force. Outside of competition, because of my interest in accuracy, most of my recreational shooting has been done with a rules compliant 10.5# 6 PPC shooting ammunition that is loaded at the range, between groups. I routinely do a lot of testing, just for the fun of it. My thoughts on this are based on experience. One good thing that has come from this thread is the idea of alternating groups of primers when loading the same case. I think that would be an improvement over the original test. Although I have not done a lot of it, I have done some chronograph work, reloading the same set of cases with different loads, and I have not observed changes in velocity based that I could associate with the number of times that a case had been loaded.

 

[fredo]

I have some experience shooting in sanctioned short range benchrest matches, loading between matches, using a set of cases all weekend. I have also done testing reloading a single case testing, loading at the range. From that experience I have observed some case to case variation in seating force, that was not present when I took the time to use a single case. Have you done these things? Because they have much less mechanical advantage, arbor presses make it a lot easier to feel differences in seating force. Outside of competition, because of my interest in accuracy, most of my recreational shooting has been done with a rules compliant 10.5# 6 PPC shooting ammunition that is loaded at the range, between groups. I routinely do a lot of testing, just for the fun of it. My thoughts on this are based on experience. One good thing that has come from this thread is the idea of alternating groups of primers when loading the same case. I think that would be an improvement over the original test. Although I have not done a lot of it, I have done some chronograph work, reloading the same set of cases with different loads, and I have not observed changes in velocity based that I could associate with the number of times that a case had been loaded.

Thanks for the reply, but you didn't answer the very simple question:

When you shoot for group score, do you shoot rounds developed from the same lot of fired brass?
Or, is it more common practice for BR shooters, in the quest for utmost accuracy, to mix & match lots of varying # of fired brass?

I sense your hesitation, as you know the answer makes my point.

Does maintaining a consistent lot of brass matter, or not?

Surely, many know the answer already & practice the method of maintaining brass consistency, by segregating via #x-fired...

So, that established, and to answer your above question:
If I were to test primers, the only thing I'd change from what's already been shared, is I'd sort brass, as I've already described. That being, only use 1xfired, FULLY prepped & measured brass, for the duration of the testing procedure. Therefore, attempting to establish a 'control' for a variable that may affect outcome, otherwise...

And, I already mentioned that I admire whomever might endeavor to test primers, since I can't be bothered. Just sayin', if you're gonna do it, do it right & don't arbitrarily pick & choose testing parameters that don't address the (not so) obvious elephant in the room. That being, brass consistency...

It either matters, or it don't. And conventional reloading knowledge says, it does...

 

[denobravo]

well said

Thanks for the reply, but you didn't answer the very simple question:

When you shoot for group score, do you shoot rounds developed from the same lot of fired brass?
Or, is it more common practice for BR shooters, in the quest for utmost accuracy, to mix & match lots of varying # of fired brass?

I sense your hesitation, as you know the answer makes my point.

Does maintaining a consistent lot of brass matter, or not?

Surely, many know the answer already & practice the method of maintaining brass consistency, by segregating via #x-fired...

So, that established, and to answer your above question:
If I were to test primers, the only thing I'd change from what's already been shared, is I'd sort brass, as I've already described. That being, only use 1xfired, FULLY prepped & measured brass, for the duration of the testing procedure. Therefore, attempting to establish a 'control' for a variable that may affect outcome, otherwise...

And, I already mentioned that I admire whomever might endeavor to test primers, since I can't be bothered. Just sayin', if you're gonna do it, do it right & don't arbitrarily pick & choose testing parameters that don't address the (not so) obvious elephant in the room. That being, brass consistency...

It either matters, or it don't. And conventional reloading knowledge says, it does...

Fredo
I agree 100%
testing demand uniformity of the test subject and only one variable change at a time
without the standardized unity of the brass nothing is proven, just assumed and assumed differently by different people ..so the results are moot

 

[BoydAllen]

All of my brass, used for any purpose is from the same lot, prepared the same way, and fired in rotation so that they all work harden together. That does not in any way prove whatever point you are trying to make or that what I have said is wrong. Have you done any loading at the range? Do you use an arbor press type seating die with an arbor press? I have done a lot of both and based on that experience I believe that using a single case firing alternate weight groups of primers is the superior way to do the test. Have you done this stuff, or do you just have opinions? I would extend that question to all who disagree. Over the years, reading forums I have read a lot of strong opinions written by fellows who just "knew" that they were right. They bandied about words like scientific and physics with absolutely no data or apparent direct experience with what was being discussed. One such topic that comes to mind is tuners. I have been amazed at the strength of opinions on that subject that have come from people who have never tried one...ever. Similarly, you claim to have the definitive answer as to how a test that you cannot be bothered to do should be done. As long as one has access to a very accurate scale, preferably one that works by magnetic force restoration, which the OP happens to own, this test should be very easy for anyone to do. While I do not have one of these scales I would really like to see results from a number of shooters who do. I have answered your question. Your turn.

 

[fredo]

well said

Fredo
I agree 100%
testing demand uniformity of the test subject and only one variable change at a time
without the standardized unity of the brass nothing is proven, just assumed and assumed differently by different people ..so the results are moot

To further prove the point...

One might also go so far as to run Quickload program.

Load up your favorite 'accuracy load' parameters for your cartridge of choice.

Then, manually adjust "maximum case capacity" up or down a few tenths.
Then note what happens to calculated muzzle velocity!!!

You all can see for yourselves how "inconsistent" brass (read: variable internal volume) can and will TANGIBLY AFFECT MUZZLE VELOCITY...

Logical conclusion?

Lack of taking the utmost care to sort & match brass to be equal/identical for testing purposes, will render any impact from 'weigh sorted' primers, secondary to the deviation that inconsistent brass allows...

Reconcile that, someone, please...

 

[fredo]

 

[fredo]

You people have way to much time on your hands to be able to make this be difficult. You test it, in your shooting system, with your "match" brass, with your normal loading regime. If you see a difference, it matters to you. If you don't see a difference, it doesn't matter to you. It really IS that simple, REALLY.

Tom

Right.

So, instead of coming to the realization that testing procedures may be rendered moot, go with "if the shoes fits" method, and smile at your obvious "success"...

As soon as one of you 'smart' testers can explain away that velocity deviation, due to variable internal volume, and how that change in velocity DOES NOT AFFECT your results, the sooner I'll be able to agree with you all...

Please, we're all here to learn! Explain how that is just 'noise', while the primer weight is what's really driving your data???

 

[Alex Wheeler]

Lets say I take 10 random cases. Say I know my gun will shoot 4" at 1k for 10 shots. I load 5 each of the 2 things to be tested. In this case primers. I shoot that 10 shot group. If it forms a 10 shot group ok. If it forms two 5 shot groups at different poi then what would be the odds that some other variable (not the one being tested) just happened to effect each of those 5 shot groups separately? Id say those odds would be very unlikely.
Just remember, you only have to convince yourself.

 

[fredo]

Odds are for gambling, not science.

Please explain how a tangible, measurable gain (or loss) of velocity due to variable case volume, can be ignored. At the same time, one can attribute data on target to the obscenely minuscule weight difference of a primer???

 

[fredo]

 

[mikeeg02]

Odds are for gambling, not science.

Please explain how a tangible, measurable gain (or loss) of velocity due to variable case volume, can be ignored. At the same time, one can attribute data on target to the obscenely minuscule weight difference of a primer???

I think you just missed Alex's point. He just stated it's a 4" gun. And while not directly stating it, hes saying that the 10 record cases are re used with the primer test. So the same cases, load, bullets, etc for a known 4" gun. Quit making this more than it is. I dont think anyone's saying that the combustion chamber doesn't matter. (Brass)

Edit: I just saw he said 10 random cases, but let's say it is the 10 match cases proven to shoot 4".

 

[CharlieNC]

Charlie, respectfully...

How can one attribute results to that of a primer, when the internal volume of the vessel (the case itself) has not been 'standardized?

Likewise, how can data be analyzed about the primer, when resultant pressure from an explosion in said vessel, is subject to varying neck tension?

With those questions un-answered, how can one differentiate the 'data' from the "noise"???

All of the other variables you mention are the noise, and you take some precaution and effort to represent these "equally" in both the light and heavy primer set. For example one would not intentionally use a different set of brass or bullets for a given primer. Technically called "randomization", or as Tom aptly put "keep it simple and do your normal best, or it doesn't matter".

 

[Alex Wheeler]

You just need to know your equipment. 1k agg. records have been shot with random un-sorted lapua cases. If you know what you can do and how your gun shoots you'll know if it matters. If you dont have the confidence or know how your equipment performs then any test you perform will leave you puzzled.

 

[dkhunt14]

Odds are for gambling, not science.

Please explain how a tangible, measurable gain (or loss) of velocity due to variable case volume, can be ignored. At the same time, one can attribute data on target to the obscenely minuscule weight difference of a primer???

Yes, but if it repeats itself over and over, with the same gun and others it is not gambling. If what you are saying is true, a person couldn't shoot a good aggregate. I can take the same set of cases and shoot the same basic groups all season long. So if you take that same set of cases and load 5 with heavy and 5 with light primers and it shows vertical dispersion, it matters. Repeat and it does the same. Matt

 

[fredo]

All of the other variables you mention are the noise, and you take some precaution and effort to represent these "equally" in both the light and heavy primer set. For example one would not intentionally use a different set of brass or bullets for a given primer. Technically called "randomization", or as Tom aptly put "keep it simple and do your normal best, or it doesn't matter".

What would you suggest the sample size be, then, to legitimize "randomization"? Not a statistician, but I suspect it'd hafta be quite large? To the point, that it'd become time prohibitive?

Given that, why not just measure & 'equalize' the brass used for the duration of the test??? You'd hafta mess with a lot less brass, and get the test done in fewer firings...

That's all I suggested, in the first place. And, if one did that, they'd known to a near certainty that they'd effectively minimized brass variability to an absolute minimum...

Yet, it seems guys wanna continue to ignore case volume, and instead, defend their (flawed) testing, since they already did the 'work' and they saw what they wanted to see?

That's fine by me. I'm just arguing that, if conclusions are to be accepted as 'sound', a scientific procedure must be adhered to. And in this instance, it wouldn't be so outrageous to standardize brass, when one seeks to measure differences in something as small as weigh,sorted primers...

Yes? No???

 

[wesmce]

[/QUOTEThis may answer some of the questons about this topic but some may find it not sceintific enough