Landric

A little while back I picked up some Winchester Small Pistol Magnum primers since I couldn't locate and standards. I loaded up some test rounds, half with standard primers and half with magnums, same powder charges, same brass, same bullets. I didn't have any overpressure signs with any of them. Here were my results (I have purposely left out powder charge weights):

.32 S&W Long, 100 grain RNFP, Trail Boss:

Ave Std. Primer: 570fps, Std. Deviation 18.08
Ave Mag Primer: 553fps, Std. Deviation 8.13

.32 H&R Magnum, 100 grain RNFP, AA#5:

Ave Std. Primer: 749fps, Std. Deviation 32.98
Ave Mag Primer: 798fps, Std. Deviation 12.11

.38 Special, 158 grain RNL, HS-6:

Ave Std. Primer: 884fps, Std. Deviation 30.27
Ave Mag Primer: 890fps, Std. Deviation 20.86

9x19mm, 130 grain FMJ, HS-6:

Ave Std. Primer: 990fps, Std. Deviation 20.79
Ave Mag Primer: 1043fps, Std. Deviation 19.70

9x19mm, 125 grain RNL, HS-6:

Ave Std. Primer: 1116fps, Std. Deviation 17.54
Ave Mag Primer: 1122fps, Std, Deviation 13.20

The only two loads that the magnum primers made any significant difference in where the 100 grain H&R Magnum and the 130 grain FMJ 9x19mm. The magnum primers seemed to be more consistent overall, though it generally didn't represent a huge change. I tested the magnums with my standard loads and the conclusion I came to is that it is safe to use magnums in place of standards in the loads I generally use. I'd test other cartridges and charge weights before using magnums in those loadings.

I'm happy with the results and I plan to use my magnum primers for the cartridges above.

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-Landric

"The Engine could still smile...it seemed to scare them" -Felix

kazzaerexys

Interesting.

Can anybody explain to me what the difference is supposed to be between standard and magnum primers? And between standard and magnum powders?

I am using Titegroup for .45 ACP now and as I am mainly reloading soft shooting rounds for plinking and competition, as I branch out to other calibers (have dies for 9mm, .40S&W, and .38/.357 waiting to get set up) I don't see a strong reason to change powders yet. If I can mix and match between standard and magnum primers across these various calibers, it will be a nice benefit when I am shopping for primers to be able to buy either type if I find them...

(By the way, where's your sig quote from???)

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SIG: P220R SS Elite SAO, P220R SAO, P220R Carry SRT, P226, P239 (.40S&W), P2022 (.40S&W); GSR 5", P6.

farronwolf

This is just a guess, so take it for what it is worth, but I would think the magnum primers will either be a little hotter, or a little longer burn in order to make sure that the whole powder charge gets ignited in the magnum cartridge.

I think you would notice more of a difference if you were using non magnum primers in a magnum than you would doing it the way your have. Going with standard in a magnum I assume you could get less than a complete burn of the powder than you would with the magnum primers.

BTW, I too bought a few thousand SPMagnum primers a while back to load with in place of the SP primers. I just haven't gotten to the point where I need to use them yet. I will back off my normal loads a tad when making the switch and see where I come out.

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jfl

Intersting !!!
There is less difference in your results than you could have with 2 different brands of the same primers ...

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jfl (NRA Life Member/Instructor - GOA - IDPA - GSSF - ex-IHMSA)

sui-juris

Thanks for posting, I thought there'd be more of a spread.

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thylordjj

I have also been playing with magnum primers in place of large pistol. I don’t have a crono to give any hard proof. But today I loaded 100 rounds of .45acp with 4.3 grains of bulls eye under a 230 grain cast WW round nose bullet and Federal 155 magnum primers. I also loaded 100 rounds the same way with Federal 150 standard primers. I marked all the rounds with the magnum primers, and mixed them with the others. That way when I was shooting I really had no clue what was what other than by feel or accuracy. I notice no difference at all between the rounds. When I recovered the brass I carefully made measurements with a micrometer to insure there were no splits or any signs of overpressure. While not as accurate as a chronograph, I will say there was no difference at all. With that in mind shoot em’ if you got em’.

Astute

Magnum primers are a little hotter. With standard loadings, little difference will be noticed. They are designed to provide better ignition for "Max Magnum" loads using slow burning powders such as H-110 or 2400. I have had no problem interchanging them with standard calibers.

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Jeff F

What is interesting to me is the standard deviations were lower with the magnum primers. This seems to be the opposite of what is a common belief (in the black powder cartridge rifle circles) that a not as hot primer will usually give you a lower SD. We even go as far as to use over primer wads to mute the effect of the primer. Interesting the obvious difference between smokeless and black powder.

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msgt/ret

Thanks for posting your results, around here magnum primers are more available than standard, I think I will just grab them instead of searching for the standard primers.

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Landric

My theory is that the magnum primers, being slightly hotter, are causing the powder to burn more consistently and therefore making the standard deviations lower. You will notice that the more significant SD reductions occurred in the cartridges that have more air space between the powder charge and bullet. The HS6 load I use for 9x19 comes close to being a compressed load in the first place, which likely means it burns pretty uniformly with standard primers.

Since I posted this I have expanded my research (still limited to small pistol primers since I don't have any magnum LP or LR, my SR are magnums, but in the case of Wolf SRM primers that just means a harder cup, not a hotter primer). I haven't seen any results significantly different from what I posted above and I've been using almost exclusively magnum primers for SP. No excessive pressure signs, no other problems. Most of my handloads are mid-range anyway, so I have been using SP and SPM pretty much interchangeably. YMMV.

__________________
-Landric

"The Engine could still smile...it seemed to scare them" -Felix