Problem: Federal Small Pistol primers in Starline .357 brass

[Richard.Howe]

I think I've got a problem: today while priming a bunch of new Starline .357 brass with Federal no. 100 Small Pistol primers, I pulled a few to test fire in my revolver.

All eight rounds I tried (no powder or bullet, just primer) essentially ejected the primer out of the case making it difficult to spin the cylinder for the next round. Then the cylinder was difficult to release due to the interfering primers.

What the heck's going on?

Did I use the wrong primer?

Is this typical for popping a primer in the absence of the rest of the round?

Are the primers undersized for spec?

Help!
Rich

 

[Richard.Howe]

ahhhhh...soooooo....

previous posts tangential to mine indicate that low pressure may be doing this. Is this a good guess?

 

[Jim Watson]

That is about what would be expected. The primer can generate about 5000 psi in the primer pocket. Naturally it is going to back out. And it will stay out without chamber pressure from burning powder to ram the case back over it. Sounds crude, but that is the way it works. That is why it is recommended to drill out the flash holes in cases for wax or plastic bullets propelled only by a primer. And not use them for powder and bullets afterwards.