Can a small rifle primer be used instead of a small pistol primer for loading 9mm auto's? I have a ton of small rifle primers and want to use them. Powders I am using are Clays, 700X, RexII. Pushing 124gr. lead cast bullets.

Thanx,
Mark

No, for two reasons. The more powerfull primer will spike pressures and second, they may seat farther out and could conceivably slam-fire. I think most 9mm hammer springs are strong enough to fire them but maybe not in all cases.

If you want to go to the trouble of reaming all your primer pockets deeper and working up all new data from scratch you might be OK.

You're better off advertising for someone to trade with you.

Sure you can do it if your pistol strikes hard enough to set off the thicker cup rifle primer.

The extra pressure spike is the equivalent of ~ 1 gr.

The 9mm brass has more like ~ 5 gr of safety margin in an unmodified 9mm chamber.

Most 9mm pistols see a guppy belly case bulge or pierced primer as the first sign of pressure trouble in a work up. Excessive recoil that cannot be compensated with usable recoil springs will precede those signs, but that is not a pressure sign. If the recoil springs are increased, at 50% more powder than max load, the springs will need to be ~ 40 pounds and the chamber will come up empty. If the mag springs are doubled, the recoil spring can increase, but at 50 pounds, the grip on the slide is at the limit of what muscle bound guys like me can do. There is also the limit of how much spring will fit. Making a triple recoil spring assembly will reach a limit of ~ 50 pounds in the volume available inside the spring cowling of the average 9mm slide. If the springs are left at the inadequate for recoil 50 pounds, then as the powder is increased further, the slide will slam into the frame harder and harder. If one calculates the momentum of the gas and projectile and resulting slide energy, that energy does not all go into the recoil spring. Much energy goes into moving the whole frame and hand. At any rate the slide and frame still get damaged as there is still enough energy to compress the three springs and hit the frame with the slide. This can damage the slide, the frame, the bones, the joints, and the nerves.

I have done overload work ups in dozens of 9mms with dozens of bullets and dozens of powders to find the real limits.

But you don't have to worry about that, you are just putting a rifle primer in a 9mm.
You probably won't be able to tell the difference.

Throat a 9mm chamber with feed ramp intrusion of no longer than .180" and chamber walls at least .100" thick steel, put 11 gr Power Pistol and 158 gr bullet in the chamber at 1.169" OAL. The recoil will make your hand hurt for an hour.
I've done that lots of times.
It hurts.

The rifle primer will either not go off because your firing pin spring is too wimpy, or it will go off and you won't be able to tell the difference. Then you can use up your rifle primers.

Small rifle primers and primer pockets and small pistol primer and primer pockets have the same dimensions:

quote:

Depth min max diameter min max
small rifle primer pocket .117 .123 .1730 .1745
small pistol primer pocket .117 .123 .1730 .1745
Large rifle primer pocket .125 .132 .2085 .2100
Large pistol primer pocket .117 .123 .2085 .2100


Height min max Diameter min max
Small rifle primers .115 .125 .1745 .1765
small pistol primers .115 .125 .1745 .1765
large rifle primers .123 .133 .2105 .2130
large pistol primers .115 .125 .2100 .2120"

Well, I stand corrected!

Not commenting on the swap, but why not trade them with someone? There are a lot of folks looking for rifle primers.