How important is primer weight

[Fuj]

After going thru "How important is a kernel" and a mention of a primer
flash being more important, I decided to have a look see for myself.
First and foremost, I'm a casual shooter that loves to compete. For the
primer end of it. I don't weigh sort. I just dump BR2's on a towel, and go
to work with my hand primer. But.....Ran out of BR2's and had to rely on
some old WLR's. I found a load and shot a match, doing well with them
but did have some that strayed from the flock. So digging out a small
100th resolution Peregrine scale, I sorted 130 WLR primers..... The primers
spanned from 5.34 grs to 5.16 grs. These two numbers were not the norm
however in this sort, But I believe large enough to skew the numbers when
fired...... Them primer outsider's will be spent for foulers and case forming.
Nothing get's wasted in this climate...... 5.34 grs is on top.

 

[garandman]

Same answer - its very impotant if it makes any significant difference in your gun. And it might make little or no difference in someone elses gun.

Equally important is false attribution - thinking the thing being tested casued the difference, when it was something else entirely.

 

[RegionRat]

About the only way to settle the matter for yourself, would be to sort another box or two and get enough of those tails to populate two strings of the extremes and see if they work together or spread apart.

 

[zipollini]

Two things that have ALWAYS lowered my SD and ES are weight sorting cases and primers. I've done comparison tests literally dozens of times and have always found the above to be true.

 

[ronemus]

There was a study published in Precision Shooting that looked at this in detail. Of the total variability in weight, most was in the cup and anvil (irrelevant to performance); the weight of the priming cake could only be determined after the fact. There was no correlation between the weight of the cake and the total weight. Feel free to weight sort them if you like, but I consider this to have been thoroughly debunked.

 

[Dub]

Same answer - its very impotant if it makes any significant difference in your gun. And it might make little or no difference in someone elses gun.

Equally important is false attribution - thinking the thing being tested casued the difference, when it was something else entirely.

this! in a nutshell

 

[JEFFPPC]

Fuji, talk to me next month at the match. I have weighed thousands, I know what your looking for, I will explain it to you. Those who don't need the gain or want to do the work will discount it with no logical reason, except they don't want too.

 

[MikeMcCasland]

I'm not going to argue with folks about what contributes most to the variation in primer weight; I'm of the belief it's mostly the priming compound.

I have weighed about 8-9 thousand SRPs total in my testing. The worst batch of the bunch was one specific lot of CCI400s, which I shot initially. Unfortunately due to my haste, I didn't shoot the two farthest ends of the ES together, but they were ~.3-.4gr apart in weight. The vast majority of the primers (within the worst lot, and others) fell within a .1gr bell curve.

When I was initially shooting these primers I expected to see a measurable improvement in my 1k vertical, and I couldn't shoot the difference. I think LR BR or a really tight shooting F-Open gun might be a different story.

This was in 1,000 yard F-T/R with a .308 and 200.20x/N150 combo. Bart/Brux/Kriger tube (I forget which one it was at the time), Panda action, NF comp scope etc... basically your "run of the mill" F-T/R rifle. Perhaps something not off a bipod, or from a better shooter could do it.

Edit: I'm starting to believe crush/depth is probably a more important factor that primer weight. My hypothesis wouldn't stand up to any level of scrutiny though.

 

[Dave M.]

After going thru "How important is a kernel" and a mention of a primer
flash being more important, I decided to have a look see for myself.
First and foremost, I'm a casual shooter that loves to compete. For the
primer end of it. I don't weigh sort. I just dump BR2's on a towel, and go
to work with my hand primer. But.....Ran out of BR2's and had to rely on
some old WLR's. I found a load and shot a match, doing well with them
but did have some that strayed from the flock. So digging out a small
100th resolution Peregrine scale, I sorted 130 WLR primers..... The primers
spanned from 5.34 grs to 5.16 grs. These two numbers were not the norm
however in this sort, But I believe large enough to skew the numbers when
fired...... Them primer outsider's will be spent for foulers and case forming.
Nothing get's wasted in this climate...... 5.34 grs is on top.

I think it is inconsequential as long as you use the same brand of primer that you rifle likes and from the same lot. Never mix primers and expect your gun to shoot the same.
dave

 

[Mulligan]

How much "Extreme Spread" is acceptable in competition?

A little background, This is in regards to a thread I read on this forum regarding weight sorting primers. I have attached a short article describing a quick test I performed to see if a real test is warranted. In the attached "quick test"- The average MV from the lightest 5 primers (actually...

forum.accurateshooter.com

CW

 

[Fuj]

Fuji, talk to me next month at the match. I have weighed thousands, I know what your looking for, I will explain it to you. Those who don't need the gain or want to do the work will discount it with no logical reason, except they don't want too.

Yeah, I was expecting 2 differing schools of thoughts and detractors
when I hit "ENTER" on the keyboard. I take internet knowledge with
a grain of salt. I've read publishing's from top shooters both pro and
con. If you know me by now, I like to experiment and follow a different
path......So here's the deal. That last session at the range, I was testing
the new R-15.5 in my 284-ELF. I had a few fliers, and the Lab radar
shown a few shots a good 20 fps faster. My last 10 shots of match
loaded ammo, put 9 where they need to be but one almost 3/8" out
and low, and the lab radar recorded 24 fps lower velocity. Removing
this shot from the series gave me an SD of 8 with the WLR's and R-15.5

I won;t have time this week to do a formal test, but I will shoot the low
end, then the high end of my sort to see what correlate's both on the
Radar and target. All the ones in between, I'll put on faith for the last
match of the year.

 

[JEFFPPC]

I am looking forward to the results. Only one way to know....try it.I like how you think.

 

[ronemus]

There was a study published in Precision Shooting that looked at this in detail. Of the total variability in weight, most was in the cup and anvil (irrelevant to performance); the weight of the priming cake could only be determined after the fact. There was no correlation between the weight of the cake and the total weight. Feel free to weight sort them if you like, but I consider this to have been thoroughly debunked.

I'm having to eat some crow here - the study by Mulligan you referenced is unambiguous; at least for Federal Match Primers the weight of the primer cake varies much more than that of the brass bits, so weighing primers is a validated approach to reducing velocity spreads, This wasn't the case for the primers used in the study I mentioned from Precision Shooting. Anybody who wants to apply this will have to verify that the primers they want to use also have small enough variation in the weight of the cup and anvil that weighing the intact primers is primarily reflecting the weight of the primer cake.

 

[Fuj]

I'm having to eat some crow here - the study by Mulligan you referenced is unambiguous; at least for Federal Match Primers the weight of the primer cake varies much more than that of the brass bits, so weighing primers is a validated approach to reducing velocity spreads, This wasn't the case for the primers used in the study I mentioned from Precision Shooting. Anybody who wants to apply this will have to verify that the primers they want to use also have small enough variation in the weight of the cup and anvil that weighing the intact primers is primarily reflecting the weight of the primer cake.

Yeah, we all eat a little crow from time to time. A little Texas Pete
helps !! I will make no statements on various brands of primers.
This ongoing test will just be within the 130 sorted WLR's. I have
3 separate batches I loaded yesterday. I chose the center sort for
the Anderson Creek UBR finals coming next weekend. The high
and lows are separated and will be tested on target over my Lab
Radar. Of all the 130 test loads, I was as meticulous as possible
to make sure all other components were spot on during sort and
assembly.

 

[Hohn]

I don’t weigh primers and won’t any time soon. My rifles/loads/shooting isn’t accurate enough to detect any difference it might make. I run 450s in everything. I figure a good load should have enough margin to shrug off most primer variation.

 

[JohnKielly]

I've found the biggest single contributor to substandard firearm performance is doubt.

 

[Mulligan]

I've found the biggest single contributor to substandard firearm performance is doubt.

You are Correct!
Attitude and self-talk have a lot to do with hero’s and zero’s.
CW

 

[D-4297]

Maybe it does make a difference for some , but it didn't for me . I weighed primers for over a year , and always selected the best for Match rounds . Didn't change much of anything I saw shooting TR . But I did learn to make my brass more consistent , and that did help .

 

[Longtrain]

I have shot competitively for 20 years, when I have to weight a friggin primer that in turn makes a difference where my bullet goes…I’ll quit.