How much "Extreme Spread" is acceptable in competition?

[seymour fish]

A number of top flight long range shooters whom I highly respect wrote about sorting primers to clearly improve accuracy. This was a year or so ago, and they dont post much anymore like a number of top shooters because they became tired of sharing their hard earned experience only to be challenged to provide proof.

Even us half-assed shooters get tired of it. Lmao

 

[seymour fish]

I might have to move to Montana! I’m picking up what your putting down.

Besides, I’ve spent 4-6 weeks there each of the last few falls....wildfires.

You know, I discovered you have as many yuppies up near the Whitefish as we do in Telluride. Yaak was ‘bout perfect!
CW

The Yak is pretty damn cool

 

[fredo]

If what you are saying is true, a person couldn't shoot a good aggregate.

Not what I "said", anywhere, at all. And, irrelevant...

Simply stated, without isolating primer weight as the ONLY variable of the test, a solid conclusion can't be achieved that states "it was the primers"...

If correlation is good enough, then I'm not gonna belabor that point. Just sayin', without isolating ONE variable & establishing ALL others as 'constants', one cannot rule them out as factors that skew your data...

And that's not to discount your data, altogether. Surely, you guys are onto something. So, why not take it a step further and see about 'cleaning up' a test to further substantiate what you've already got to ponder?
What's the harm in having more, relevant data, than you already have?

 

[seymour fish]

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.

Yes, and then shoot five from the center of the weight curve distribution. See which group if any these went into. The value for long range would be to determine what weight range of primers out of An average Lott might equal your best lots, which don’t come along every day, within the same brand, then apply to various other brands to see who’s hot and who’s not. Ok, this AInt what Mulligan set out to investigate, and no offense intended, but let’s not dampen the enthusiasm here with any schoolmarm bs. Keep it rolling

 

[jr600yd]

Well the real question is “is all this work worth it?” Sometimes we just take the fun out of it.

 

[seymour fish]

Well the real question is “is all this work worth it?” Sometimes we just take the fun out of it.

If it helps answer the age old question of which steps are important/useless, I would spend time otherwise wasted , on this and net out improvement fer sher

 

[wesmce]

Not what I "said", anywhere, at all. And, irrelevant...

Simply stated, without isolating primer weight as the ONLY variable of the test, a solid conclusion can't be achieved that states "it was the primers"...

If correlation is good enough, then I'm not gonna belabor that point. Just sayin', without isolating ONE variable & establishing ALL others as 'constants', one cannot rule them out as factors that skew your data...

And that's not to discount your data, altogether. Surely, you guys are onto something. So, why not take it a step further and see about 'cleaning up' a test to further substantiate what you've already got to ponder?
What's the harm in having more, relevant data, than you already have?

If it helps answer the age old question of which steps are important/useless, I would spend time otherwise wasted , on this and net out improvement fer sher

If you all would like some interesting reading google or just search high speed measurment of rifle primer blast

 

[seymour fish]

If you all would like some interesting reading google or just search high speed measurment of rifle primer blast

Read all his stuff back in the day. Was Solid

 

[BoydAllen]

This started out as a simple, well written post about a test to determine whether variation in weights of primers can cause significant variation in velocities. Evidently some of you are threatened by the idea that someone is doing testing that you have not thought of,or if you have do not want to be bothered with doing....so you are hammering this fellow with what you think, as if it is as significant as what actually does happen. This is common on the internet. This was not a test of whether these magnitudes of velocity differences show up on long range targets. You might want to reread that last sentence.

 

[fredo]

If you all would like some interesting reading google or just search high speed measurment of rifle primer blast

Will do, thanks for the tip...

In the meantime, did anyone want to venture into if & how case volume affects muzzle velocity?
Certainly those who developed QUICKLOAD program knew enough to calculate for it, so still at a loss as to why a primer test would ignore it??

More specifically, why the notion of accounting for it during a primer test is getting such flack? Simple question, really...does it matter, or not?

Then, there's still the other topic about brass consistency, regarding neck tension variation from subsequent firings. But, let's stick with addressing case volume variation, as it pertains to pressure, velocity, and POI dispersion on target, shall we?

Or, just keep ignoring it & pretend it doesn't exist. Whichever...

 

[wesmce]

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

 

[fredo]

https://arxiv.org/abs/1203.2701
Link to download for paper on primer blast waves...

 

[wesmce]

This started out as a simple, well written post about a test to determine whether variation in weights of primers can cause significant variation in velocities. Evidently some of you are threatened by the idea that someone is doing testing that you have not thought of,or if you have do not want to be bothered with doing....so you are hammering this fellow with what you think, as if it is as significant as what actually does happen. This is common on the internet. This was not a test of whether these magnitudes of velocity differences show up on long range targets. You might want to reread that last sentence.

The article high speed measurment of rifle primer blast pertains to only primers it may help answer some of his questions in his testing.I think all testing is a good thing

 

[fredo]

Quote from link, above:

METHOD
Rifle primers work by the impact detonation of high- explosive compounds (usually a combination of lead styphnate and lead azide in modern primers), which then ignites the propellant charge. The measurement method is simple: a firearm loaded with a primed cartridge case without any gunpowder or projectile has all the essential elements of an explosive driven shock tube whose shock wave is emitted from the muzzle after the primer is detonated by the firing pin. The blast wave measured at the muzzle depends on the strength of the primer without the confounding factors (bore friction, neck tension, powder charge, bullet bearing surface, cartridge case variations, etc.) that affect other methods of inferring primer strength and consistency.

End quote

Soooo, the primers were tested in manner which negated the "confounding factors" which include "neck tension", "cartridge case variations", etc...

I rest my case.

 

[denobravo]

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.

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

 

[seymour fish]

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

You miss the point. These are “random” cases which are known to agg 4”, so hardly the random you are familiar with

 

[denobravo]

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???

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

 

[denobravo]

You miss the point. These are “random” cases which are known to agg 4”, so hardly the random you are familiar with

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

 

[seymour fish]

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

And you might be taking concrete to a new level. Amusing

 

[BoydAllen]

Quote from link, above:

METHOD
Rifle primers work by the impact detonation of high- explosive compounds (usually a combination of lead styphnate and lead azide in modern primers), which then ignites the propellant charge. The measurement method is simple: a firearm loaded with a primed cartridge case without any gunpowder or projectile has all the essential elements of an explosive driven shock tube whose shock wave is emitted from the muzzle after the primer is detonated by the firing pin. The blast wave measured at the muzzle depends on the strength of the primer without the confounding factors (bore friction, neck tension, powder charge, bullet bearing surface, cartridge case variations, etc.) that affect other methods of inferring primer strength and consistency.

End quote

Soooo, the primers were tested in manner which negated the "confounding factors" which include "neck tension", "cartridge case variations", etc...

I rest my case.

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.