Funny looking primer marks with my MPA9mm

[m1a1driver]

Been shooting this MPA mini 9mm for a while now, all the primers look this way. The one thats popped "out" are factory loads, the one thats popped "IN" are my reloads. It does this with all the ammo I shoot, however the brass resizes fine and i'm able to reload all the brass like this with no problems. Any ideas why it does this?

[ireload]

Is it possible for you to take a pic of the area where your firing pin hole is located? First time I've seen that. Heck I thought you would be posting a indentation of a primer fired from a Glock.

[rdmmdr]

Oversided firing pin hole with a low wieght pin. the facotry loads are hotter then your reloads and forcing the primer shell back in to the bolt face firing pin hole, Forcing the firing pin back. Don't own one so I don't know if it is normal. But looking at the pictures tells me that you have a firing pin hole of about .136 dia so figuring max pressure of 35,000 psi of chamber pressure that would result in about 500 lbs of force over the area of the hole. By comparison the firing pin holes in both my 357's, 243 and the 380 are about .075 dia = about 175 pound of force on the hole area, While I would talk to the manufacturer, if you are not rupturing primers it is probably ok.

[GunDog]

Why not send your photos to Masterpiece Arms and ask them about it? I own and shoot a MPA mini-Mac as well but, haven't seen this kind of problem.

[GeoffLinder]

Yup, oversized firing pin hole and hot ammo causing primer to flow into firing pin hole. Not necessarily dangerous, but not necessarily a good thing in the long run.

I agree about contacting the Mfgr and showing this to them.