Small pistol versus small rifle primers in .357 Mag/.38 Special

[megasupermagnum]

I received an email from CCI with the same info. I never got a clear answer on any other brand, but I swap CCI SPM and SR without worry. I usually find the SPM cheaper, and more available so I use those.

I heard the same thing with 327 federal about using small rifle primers, and that can run up to 45k psi. I've used all primers successfully, and choose the one that is most accurate or consistent with that particular load. Another note about CCI primers, the small pistol cup thickness is EXACTLY THE SAME is the small pistol magnum. The only powders I've found so far that work better with the magnums in 327 federal is AA #9 and H110. Every other powder I have much better results with standard primers. The Federal small pistol primers are very thin, and do get nice and flat with max loads, but I've never had one pierce or leak.

[porthos]

ok: how about using large rifle primers in large pistol cases or the other way around??

[Dave W.]

ok: how about using large rifle primers in large pistol cases or the other way around??

Large rife primers are longer than large pistol primers, so they will not seat properly in pistol cases. Do not substitute one for the other.

[BNE]

Great read, you all taught me something today! Thanks!

[Dragonheart]

Large rife primers are longer than large pistol primers, so they will not seat properly in pistol cases. Do not substitute one for the other.

Dave is right, you could probably get away with it in a pinch with a revolver, but I would be afraid of a slam fire in a pistol. I have interchanged the small primers a lot, but never tried the large.

[Landshark9025]

I received an email from CCI with the same info. I never got a clear answer on any other brand, but I swap CCI SPM and SR without worry. I usually find the SPM cheaper, and more available so I use those.

I heard the same thing with 327 federal about using small rifle primers, and that can run up to 45k psi. I've used all primers successfully, and choose the one that is most accurate or consistent with that particular load. Another note about CCI primers, the small pistol cup thickness is EXACTLY THE SAME is the small pistol magnum. The only powders I've found so far that work better with the magnums in 327 federal is AA #9 and H110. Every other powder I have much better results with standard primers. The Federal small pistol primers are very thin, and do get nice and flat with max loads, but I've never had one pierce or leak.

emphasis mine

I would question this. You may be right and it would be worth checking, only because my experience has been different. I have a S&W Mod. 66 that I shoot mostly 38 SPL loads out of. I use CCI-500 religiously. At one point during "The Drought" (I think it was 2015) I tried some CCI-550 and got a lot of light primer strikes. This was the only time I experienced that. I was trying to do some load workups to see if there would be a difference and it happened often enough to make it not worth it. I'd say at least one every 10 rounds.

This particular revolver is old, I acquired it second hand and it had been shot a lot. So it's possible it has a light spring or a worn firing pin. All I know is that with this particular firearm, in the several thousand rounds before and after, using CCI-500 I never had a failure, but with the few I tried with CCI-550- it was pervasive.

Naturally, this was all using the same cases, same press, same everything else.

[Rcmaveric]

My understanding is the that the difference between SPM is SR primers is the hardness of the primers. The SR are harder to resist the higher pressures of riffles. While the SPM is softer for use in lower pressure rounds IE 38 spl.

[Lloyd Smale]

there is more variation between the cup hardness of different brands then between different primers of the same brand. A cci small or large standard pistol primer is harder then a fed mag small or large rifle primer.

My understanding is the that the difference between SPM is SR primers is the hardness of the primers. The SR are harder to resist the higher pressures of riffles. While the SPM is softer for use in lower pressure rounds IE 38 spl.

[Thundarstick]

My experience with the 327 FM is that almost everyone gripes about the double action revolvers having a hard trigger pull. I started replacing springs in one of mine and polishing a little. It would shoot 32HR mags with SP primers 100% but with factory Federal rounds would give FTF about 25% of the time. This before I was aware the factory loads do use SR primers. I've found through experience that SPM primers and SR primers do seem to take more or less of a bit to set them off. My advice would be to test the SR primers in your gun for sure!

[MT Gianni]

My understanding is the that the difference between SPM is SR primers is the hardness of the primers. The SR are harder to resist the higher pressures of riffles. While the SPM is softer for use in lower pressure rounds IE 38 spl.

That is what we have been told since the 50's in gun magazines. It currently appears that bean counters may have decided it was easier to stock one materiel. Eash manufacturer is different though I can see this happening. I know my 1955 I frame 32 long will go bang on recent SR primers.

[megasupermagnum]

emphasis mine

I would question this. You may be right and it would be worth checking, only because my experience has been different. I have a S&W Mod. 66 that I shoot mostly 38 SPL loads out of. I use CCI-500 religiously. At one point during "The Drought" (I think it was 2015) I tried some CCI-550 and got a lot of light primer strikes. This was the only time I experienced that. I was trying to do some load workups to see if there would be a difference and it happened often enough to make it not worth it. I'd say at least one every 10 rounds.

This particular revolver is old, I acquired it second hand and it had been shot a lot. So it's possible it has a light spring or a worn firing pin. All I know is that with this particular firearm, in the several thousand rounds before and after, using CCI-500 I never had a failure, but with the few I tried with CCI-550- it was pervasive.

Naturally, this was all using the same cases, same press, same everything else.

I can't speak of hardness, but the thickness of CCI 500, 550, and 400 are all .020" thick cups the best i can measure. Federal 100's are only a little thinner at either .016" or .017", but a lot softer. If you're not careful, you can pre-flatten Federal primers when seating them. I would think hardness would effect strength, but my point was that every regular small pistol primer I've tried has held up to 45k psi loads no problems. I have not noticed any gas leaking or pierced primers. Certainly you wouldn't run into problems with the slightly lower pressure 357 mag.

In response to both Landshark9025 and Thundarstick, I tried a 9# hammer spring in my 327 federal GP100, which most people will tell you it didn't work for them. I had a light hammer strike about 1 in 20-50 shots, and both CCI 500 and CCI 550 primers performed identically poor. I never tried Federals with that combo, as I did not want a gun that could only use one primer. I tried a 10# hammer spring, and did not have a misfire in 100 shots, but it just seemed like the hammer was too slow to me, and I did not trust it. I now have the Wolff 12# in the gun, with zero misfires and hundreds of rounds downrange, including factory ammo. I do not have a trigger pull gauge, but double action is not bad at all, I would bet around 9#.

Realize this is just my experiences, so take it with a grain of salt. I did just shoot a bunch of ammo primed with brand new CCI 500's. I can measure them tomorrow to see if the thickness has changed from the last batch I had bought maybe 5 years ago.

[nicholst55]

Some action pistol shooters use nothing but small rifle primers. As long as your gun(s) will ignite them reliably and you work up to your load with them, I personally see no issues. I have loaded a small amount of .40 S&W with SRPs, and experienced no problems.

[sutherpride59]

Has anybody tried the opposite and used small pistol magnum primers in smal rifle loads? Seems like small pistol magnum primers tend to be cheaper.

[megasupermagnum]

Has anybody tried the opposite and used small pistol magnum primers in smal rifle loads? Seems like small pistol magnum primers tend to be cheaper.

Yes, I have used CCI 550 in 223 remington. No difference from the 400.

[dale2242]

I have used small rifle magnum primers in my GP100 357 with heavy loads of slow powder with no issues.
I have never had a FTF with them....dale

[ioon44]

Has anybody tried the opposite and used small pistol magnum primers in smal rifle loads? Seems like small pistol magnum primers tend to be cheaper.

I loaded F-100 small pistol primers in .223 by mistake and the primers ruptured so soft pistol primers won't work for small rifle.

[dwtim]

At least with CCI SP primers, I just confirmed that the dimensions are the same with my mic.