Magnum vs. standard primers

Boolit Master Join DateJan 2010LocationTom, in Gloucester, VAPosts761

As I have been unable to find any standard primers for sale, but have had opportunities to buy magnum primers, I did. Yesterday I did a test comparing the two. Using Remington 2-1/2 standard large pistol primers, CCI 350 magnum large pistol primers, and two different military surplus powders, M9 and #105, I prepared four samples of test ammo. M9 and #105 powders were obtained from Jeff Bartlett at GIBrass.com. Burning rate appears to be similar to Unique. The two powders appear to be the same, but do not meter the same. M9 charges throw a little bit lighter than #105. The difference could easily be attributed to them being different lots of the same powder.

The test cartridge was the 41 Remington Magnum with 240 gr LBT WFN GC bullet. Moderate loads of each powder were assembled using standard primers, and loads using 1/2 grain less powder were assembled with magnum primers. Five shots of each combination were fired over the chronograph. Mean velocities of the four treatments were compared using ANOVA. There were no significant differences in average velocities, which were all very close to 1150 fps.

Magnum and standard primer velocities were pooled and variances were compared using the F test. There was no significant difference. However, it appeared to the Mk I eyeball that there may be a difference in variance, and a repeat test with a larger sample size might indicate a significant difference, with magnum primer loads being more variable. However, given that the difference is not significant at this level, even if found to be different with a larger sample size it probably is not important.

In conclusion, substituting magnum primers with an appropriate adjustment in charges and avoiding maximum loads can be a successful expedient during times of primer shortages.

In conclusion, substituting magnum primers with an appropriate adjustment in charges and avoiding maximum loads can be a successful expedient during times of primer shortages.

That is indeed the key to substituting primers.

Larry Gibson

I choose to use magnum primers in some loads willingly.
unique seems to burn pretty darn clean in many cases with the addition.

it's all an educated guess,,,, till the trigger is pulled.

the more i find out about shootin boolits, the more it contradicts everything i ever learned about shooting jaxketed.

If only I had your problem, my local supply has 20-30k Win LP, and that's about it, occasionally Win SP, or some CCI 350, but I haven't seen Magnum SP in 6 months.

The key is working loads in the .41. But standard primers will give better accuracy.
You read a chrono but no groups.
A spark will fire, that is all.
OK, you got the same velocity so now we need to see the groups at 50 yards from both primers.
I will go along with not finding primers and anything to keep you shooting is good. Use what you can get.
Please put the chrono away, it does not show accuracy.

Boolit Buddy Join DateMar 2013LocationI challenge your middle of nowhere, and raise you 5.Posts56

I've heard it said that magnum primers were created to solve a problem that didn't exist.
I think an interesting test would be to prime two cartridges, one with regular and another with magnum, and seat bullets on them with no powder.
Fire each one, and see how far they get lodged in the barrel.
This might be a rather accurate test as to the extra pressure of the magnum primer.

Thanks for the testing. I plan to use up the magnum LP primers I was able to find over the summer, and keep my stash of standard LP primers for just in case.

Anyone have experience loading with LP mag's in the .45 ACP?

Thanks for the testing. I plan to use up the magnum LP primers I was able to find over the summer, and keep my stash of standard LP primers for just in case.

Anyone have experience loading with LP mag's in the .45 ACP?

OH NO. The LP is too much and the ACP is better with a SP primer.
ONLY AS A LAST RESORT.

Boolit Master Join DateNov 2009Posts891

Reminds me, I need to get a copy of Chicken Little for my grandson.

OH NO. The LP is too much and the ACP is better with a SP primer.
ONLY AS A LAST RESORT.Are you joking here? I found some LPM and was going to sub them into a 44Mag with a reduction in powder on target loads and was thinking of trying them in my 45ACP starting on the bottom end.

Found that using Mag SR primers in .223/5.56 full-power loads using milsurp powder (pulldown 844) made no difference at all on the Chrony. Am loading all those 5.56 loads for my SIL now with magnum primers to preserve my STD SR primers for better things. Don't load any pistols that use the large primer so can't speak to that.

"You are not a hoarder until you have exceeded a lifetime supply"

Nothing says you can't use them if loads are worked but I am sure you will see a difference in how they shoot.
I am only thinking of accuracy.
The reason I don't chrono to look for accuracy is many of the best loads will show larger numbers.
The ACP is also a very small case and a LP mag is getting close to not even needing any powder!

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Abbreviations used in Reloading
Pointed Soft Point "Core Lokt"

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