Wednesday, May 27, 2015

A difference between pistol and rifle primers Updated

Pistol primer on the left, both fired from a 1903A3 Springfield.

Update: Yes, I should've explained this further.  The pistol primers were used in some of the mouse-fart loads as an experiment; some have reported getting better accuracy with them than with rifle primers in such loads.

Generally pistol primers are a bit 'softer' in the cup than rifle, so the strike that left a nice round indent in a rifle primer left a BIG dent in the pistol primer.

No, I would not use a pistol primer in a full-power rifle load; that could lead to a real problem.


tkdkerry said...

Help me out here. I'm not learned enough to know what I'm looking for in the picture. Is the pistol primer by chance separating from the case?

Pawpaw said...

Yeah, pistol primers are softer. Why would you use a pistol primer in a rifle load? And, were those full-power loads? I would expect that the pressure from the charge firing would have flattened the pistol primer a bit.

Arthur said...

Huh, large rifle primers are also taller than large pistol primers, so if you bottom out a pistol primer in a rifle pocket it'll be visibly seated too deeply.

Small Rifle/Small Pistol .118" to .122".
Large Rifle .128" to .132".
Large Pistol .118" to .122".

I found all of this out when trying to re-use Sellier & Bellot 7.62x39 brass and found that their primer pockets were cut shallow. I had to get a pocket cutter and deepen them.

Jerry The Geek said...

Merely as an aside ... when I load .38 Super ammunition (for iPSC competition), I use Small Rifle rather than Small Pistol primers. The pressure spikes in a competition pistol with a compensator tend to be quite robust. The rifle primers help prevent any kind of 'blowback' which might occur with the softer pistol primer.