Punctured Primer

[lugerholsterrepair]

One is one thing..8 or 10 is another. Pierced primers are a serious issue. I would take a close look at all aspects of the barrel and bolt..firing pin etc. Look for any brass shaving obstructing the bore/chamber area..clean this well..scrub the chamber with a bore brush. I don't believe your pistol has the stepped chamber..it may be tapered. Disasemble the bolt..push the firing pin forward in the pin hole and see how far it protrudes. Inspect the shoulders of the pin. Look at your FP spring too.

The first thought is overpowered ammunition when you get pierced primers. That's why I asked about flattening. Flattening is an indication of too much cup pressure.

It's a matter of elimination until you decide if it's caused by ammo or the pistol. If you fire some Winchester White box and get a pierced primer..it's back to the pistol and as Marc indicated, could be a headspace problem. I would want to eliminate ammo after a close inspection of the toggle train.