Primer weighing test

H

hounddawg

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It was completely unremarkable, that is about the best that can be said. I loaded 50 rounds of .260 Remington with 40.0 grains of H4350 and Barnes match burner 140's. twenty five rounds were loaded with CCI 200's picked randomly from the tray. Twenty five were loaded with primers weighed on my A&D 120 to the milligram minus the error rate of plus or minus 1 milligram.

shot five groups of five rounds each @100 yards over a chrono with five mph crosswinds blowing from 9 to 3

average group size for the non weighed groups was .62 inches, smallest group at .51 inches, largest at .76 inches. Group height for all 25 shots was .68

average group size for the weighed primer groups was .6 inches, smallest at .49 inches and the largest was .8 inches. group height for all 25 was .66 inches

random weight velocity SD for all 25 rounds was 20 FPS
sorted weight SD was 23 FPS

To me this rabbit hole is not worth exploring any farther
 
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good to know. Had been thinking about this since the other post. Your time and primer expenditure is much appreciated.
 
Thanks, it was a fun way to spend a afternoon. This barrel is not the best barrel that has ever been on this rifle but I figure I may as well get some use out of it. I have plenty of powder and LRP's to use it to play with.

I will not be wasting my small rifle primers and Varget repeating this test with SRP's
 
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no idea Bart and that is the core of the problem. there is no way to determine that without firing the primer. I could have numbered and weighed each primer before and after each firing to determine how much was pellet but why bother. My purpose in doing this little experiment was to see if weight sorting before firing made a difference on paper or on the chrono. It did not so my question was answered. I see no need to spend any more time on the subject
 
To me this rabbit hole is not worth exploring any farther
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Have you weighed each bullet? Back when I was intent upon max accuracy, to my dismay I found that my match bullets had significant variation in weight from the same box.
 
yep went the bullet weighing and case volume route also. Could not tell any difference on paper with either. I think a lot of us of chase our tails down rabbit holes when our scores plateau. Rabbit holes and theory are ok for cold winter days but for improving scores there is no substitute for practice. Of course natural talent trumps everything
 
hounddawg said:
yep went the bullet weighing and case volume route also. Could not tell any difference on paper with either. I think a lot of us of chase our tails down rabbit holes when our scores plateau. Rabbit holes and theory are ok for cold winter days but for improving scores there is no substitute for practice. Of course natural talent trumps everything
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This has been my experience. I’ve done everything I can to make my equipment and ammunition as consistent and accurate as possible and have come to one conclusion. In my case I’m a consistent sub MOA shooter, usually 3/4 MOA and am more than happy with that. Every once in a while I’ll shoot that ragged one hole target, but cannot consistently repeat that.
 
I know shooters who shoot very good that do weight the primers, I don't. They also measure their bullets on the ogive, but don't weight them. I try measuring both to the ogive and overall length. I have tried everything I have heard about except lubing the bullets, and that may be next. I can't get my head around lubing and bullet "hold", how does that work?
 
scatterbrain said:
I can't get my head around "lubing" and bullet "hold", how does that work?
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"Lubing" usually means coating bullets with molybdenum disulfide (moly coat) so they're more slippery. Theory is they're more accurate.

"Bullet hold" typically means how tight the case neck grips the bullet. SAAMI calls it release or pull force needed to push bullets out of the case neck, typically in pounds. Arsenal specs for 7.62 NATO service ammo is 60 pounds minimum, match ammo is at least 20 pounds. Some handloads for match ammo have about 1 pound bullet release force. For 30 caliber bullets, each pound of pull/push/release force needed requires about 13 pounds psi pressure to move it. Its cross section area is about 1/13th square inch.
 
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It would be a false assumption to start with the premise that primer weight has affect.

If powder varies by 10%, then primers?

Starting place would be how much energy does a primer release. Then see what weight does to that measured energy level.

Primer makes may have methods but have not ever heard of it.
 
Thank you , I'm glad I'll never need to go down that rabbit hole because you did for me . ;) Just the expense of a scale capable of weighing those differences would be something I'd hate to spend just to find out primer weight has no effect . :mad:
 
the real problem is that when you weigh the primer you are not sure how much is the pellet and how much is the anvil/cup etc. To weigh it before and after will give you tat answer but what good does it do? It's not like you can use it a second time

Also I figure it is like case volume and bullet weight. An extra CC of volume or an extra .1 gn of weight is pretty insignificant compared to the energy the powder is generating. Add in shooter error and you have some back of the gunshop theorizing BS to argue over but nothing that will make a damn when you are looking through the mirage at a target several hundred yards out with a five mph intermittent crosswind

The longer I play at this game the more I realize the only road to improvement is through hard work and lots of rounds fired. You cannot buy pixie dust through Midway no matter how anal you get and how much money you spend
 
It may have been Col. Hatcher who knew that bullets need to be at least a few ten-thousandths inch larger than the barrel's groove diameter for best accuracy..

Why else would arsenal 173 grain FMJBT .3086" match bullets mic larger than M1 and M14 barrel groove diameters?

When the British commonwealth started shooting 7.62 NATO M80 ball ammo's. 3070" bullets in their fullbore rifles, best accuracy was with 1:13 or 1:14 twist 30 inch barrels having. 3065" groove diameters

And all the best match winning record setting barrel's groove diameter smaller than the best match bullet's diameter.
 
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It may have been Col. Hatcher who knew that bullets need to be at least a few ten-thousandths inch larger than the barrel's groove diameter for best accuracy..

Why else would arsenal 173 grain FMJBT .3086" match bullets mic larger than M1 and M14 barrel groove diameters?

When the British commonwealth started shooting 7.62 NATO M80 ball ammo's. 3070" bullets in their fullbore rifles, best accuracy was with 1:13 or 1:14 twist 30 inch barrels having. 3065" groove diameters

And all the best match winning record setting barrel's groove diameter smaller than the best match bullet's diameter.
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Thanks for that info but what does that have to do with sorting primers by weight :confused:
 
Thanks for the quick run-through. I'll probably still do my test in 308 when it warms up a little, as I've got another co-experiment to conduct using the same materials, but you've confirmed other variables are normally going to be dominant. I will include pre and post-firing cups and anvils weights to learn how much variation they have. PITA, since all the residue has to be cleaned out first, but doable.
 
That would be interesting Nick, good luck in cleaning the residue and keeping the cases in the right order. I have not depinned those that I shot, if I had a ultrasonic I would clean them to see what the variation in the metal parts would be. I could not match them to order fired and velocity however. I toss my all of my shot brass into a container of soapy water for the trip home from the range.

It might be worth repeating in a more accurate rifle also. That barrel has never been what I would call impressive no matter what I run down it. Good news it is .5 - .75 out to 850 yards, bad news is it shoots .5 to .75 MOA out to 850. If nothing else it consistently mediocre. Kind of like a lot of my shooting in a way
 
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