Does the primer make a difference?

[gonefishin]

When I bought the components to make up my first loads, the local store that I was in only had Remington SPPs, so that's what I bought. They work fine and I've got good data for the rounds that I used them in. I'm almost out, so I went to buy more and found a box of 1000 Winchester SPPs and a good price so I bought them. They also had Federals, which I understand are very popular, but the giant box they put them in versus the Winchester pushed me toward the Win. So anyway, should I expect any noticeable difference in the velocity/power factor of my load using the Winchester primer vs. the Remington? I'm guessing no, but I'd like to hear from more experienced folks. Thanks!

[superdude]

maybe so, maybe no.

that's about the best answer you'll get. there might be minor difference in velocity depending on your load. i have some data for that, where i looked at 6 different powder charges with 231 and a 124 grain bullet in the 9mm.

comparing all the pistol primers (remington, winchester, federal, cci; standard and magnum) there were some differences in velocity, but the differences weren't always consistent. extreme spread averaged 20 fps which isn't much. that averaged to about 1.3 to 2.9% of the velocity. that extreme spread was less than the extreme spread for a given 10 shot string.

velocity with the winchester SPP was pretty similar to the remington 1 1/5 - sometimes a little more, sometimes a little less, so no obvious difference.

so, maybe you'll see a difference. and maybe not. but i think the bottom line is that you'll have to see if it does for your load, but the odds are that it probably won't be much of a difference. i could be wrong!

[UW Mitch]

Chrono your old rounds and chrono some new rounds with different primers and see for yourself. I didn't notice any statistically significant difference between brands of small pistol primers - various between primers was within variation of the "the same load". I did notice a small and expected increase in velocity and muzzle blast when I had to go to a small magnum primer in 40S&W. And when I say had to - my old EAA Witness needed Federal primers to reliably ignite and I couldn't find any standard so I switched to magnum which were available.

The biggest difference for me is the hardness of the cup - so on some of my revolvers and that Witness I need the softer Federal cup and on something like 9Major, I'm using a Winchester small rifle primer for the increased hardness.

~Mitch

[pjb45]

I have a lot of Chrono data for VV320 and Winchester, Magtech, Wolf, and Federal primers, including SR, SP, SRMatch, SPMatch, and SPMagnum. I did not experience the 10-15 fps increase often attributed to SR or SP Magnum. The ammo all had about the same standard deviation despite the primer. Each Chrono session involved more than 30 rounds, often shot in three shot groups to emulate the Chrono at Nationals. The power factors rarely varied from 170-171 from my Chrono and the Chrono at Nationals. I will buy whatever Winchester or Federal primers that are on sale or available.

The only real variance has been the brass. Various brass volumes seem to be the real difference in velocity.

As a side note, my guns had reliability issues with Wolf and Magtech primers. It was not the primers fault just my light triggers.