Help with primer problem.

[MAP]

I'm having some odd issues with small rifle primers in my reloads. The load is 25.5 gn of TAC, once or twice fired cases, Hornaday 55 gn FMJ bullets and older Winchester small rifle primers. The primers are pierced on the outer edge. The below photos are the best way for me to describe the issues. It isn't happening with all of the loads in the same "lot". Today I had the below 2 problem primers out of 40 runs fired.

Thanks for y'alls help.




Next pic from November '14

[Duman]

Stating the obvious, it looks like the primers were struck, ignited, slightly backed out of the primer pocket, and the burning powder eroded past a pinhole in the primer. What caused the pinhole, dunno, still thinking about it. Maybe there were some non-uniformities in the primer pocket.

Would you happen to have more unloaded cases, and a primer pocket uniformer?

[cstone]

Are you certain the outside holes were not there before firing?

I assume all rounds fired from the same firearm. Have you inspected the bolt face of that firearm?

[Hoser]

Might be small pistol primers.

Check your bolt face for some serious pitting.

[MAP]

Might be small pistol primers.

Check your bolt face for some serious pitting.

They were definitely small rifle primers. It does cause serious pitting on the bolt face.

Mike

[DenverGP]

I saw a bunch of reports of defective primers causing this issue. In one case, they were relatively new primers which Winchester determined they primers were defective and replaced the primers and compensated the person for damage as well. In another case, the Federal primers used were very old, and Federal suggested they were probably stored near some corrosive substance. Pics in both situations looked identical to your pics.

Also see reports of similar issue where high pressure pushes the primer part way out, and the gases leaking by the primer cut a pinhole. The load data I've got shows 25.8 as the max load for a hornady 55gr fmj.

[Alpha2]

How are you removing the crimp from the primer pockets? It looks like a lot of metal was removed. If the crimp wasn't removed, that could have damaged the wall of the primer inserting the primer.

[Zombie Steve]

Sure looks like you have gas leaking around the primer pocket. Too much pressure is a possibility (I don't use TAC, but a quick glance at Ramshot's data tells me you're around max), or if the primer is backing out to the point where it causes gas to come around it, I'd call it a headspace problem. Are you ever getting case head separations? The primer shouldn't have that much room to back out - you may be pushing the shoulder back too much during sizing.

Defective primers? I don't know, but it's an easy thing to eliminate - get some different primers.

Last but not least, as Cstone suggested, you might have something on the bolt face that is popping it.

[MAP]

I saw a bunch of reports of defective primers causing this issue. In one case, they were relatively new primers which Winchester determined they primers were defective and replaced the primers and compensated the person for damage as well. In another case, the Federal primers used were very old, and Federal suggested they were probably stored near some corrosive substance. Pics in both situations looked identical to your pics.

Also see reports of similar issue where high pressure pushes the primer part way out, and the gases leaking by the primer cut a pinhole. The load data I've got shows 25.8 as the max load for a hornady 55gr fmj.

I think you are on to something with defective primers. Same load with different primers run perfectly. Once the issue started I contacted Western Powder with my load data and chronograph results. They said the load falls into a safe pressure range.

I have about 300 loaded round left from this lot of primers. I'm going to pull those loads and reprime the brass.

Thank you for all of the responses and suggestions!

Mike