Primer Seating Causes Firing

[1hole]

If that question is directed at me and my Dillon, it was manipulated just vigorously enough to not have a high primer and no more. I even tried adding a step to clean the primer pocket but that didn't make any difference.

CP, my post wasn't "directed" at all, as such, it was just my puzzlement about what might have caused the primer to go off. I doubt that the press being a Dillon had anything directly to do with your event but you did make that mention up front. The "manipulation" question wasn't about how much lever pressure was used, it was about HOW that lever pressure was applied - specifically, was it pressed down slowly or rapidly snapped down??

[Firephoto798]

I recently bought and started using a 550c for 357mag. After loading about 50 rounds I noticed that the rounds were coming out with a small dent in the primers (WSP), like a light firing pin strike. I found debris on the primer seating pin that looked like a compressed chunk of powder. After cleaning it, the dents went away. I now watch the pin closely and occasionally find powder flakes there and clean the pin regularly before it builds up to a larger chunk. I am not sure why I am getting powder flakes there to start with.

[Patrick L]

The one primer detonation I had in my entire 35+ years of reloading was on a shotshell press. A piece of spilled shot rolled into the little hole that the new primer drops into, on top of the seating punch.

[alamogunr]

OP having prior problems with Dillon and priming.

http://castboolits.gunloads.com/show...B-Primer-Setup

I guess I'm convicted.

[abunaitoo]

Must have been scary.
Never had that happen to me.
I've read primers are kind of hard to set off.
I have crushed a few primers seating, but none ever went off.
Knock on wood.
Friend deprimes live primers, and sometimes one will go off.
He's kind of used to it happening.
Said it still makes him jump.
My friend Ed had the primer tube go off.
It made a nice hole in the roof.
He said he almost soiled his pants.
He didn't get hurt.