Pieced primers / primer flow

[mtnlvr]

I've done a lot searching but can't seem to find ideas on how to fix this. I've always had some catering or flow of the primer into the firing pin hole, but today I had my first pierced or blown primer and a piece plugged into the FP hole. For the record, this is a reweld semi auto with a brand new RTG second pattern bolt setup configured in .308. I do seem to have excess pin protrusion, but when I pop a primer with no bullet, the indentation appears pretty normal. This appears to be internal pressure causing the primer to flow back around the FP.

[JBaum]

If the firing pin protrusion is good, that leaves checking the headspace.

[mtnlvr]

What's the concensus on pin protrusion? 0.045“-0.057"?

And is it OK to file and polish the tip?

Headspace was checked a few years ago. I could check that again.

[JBaum]

According to the firing pin protrusion gauge drawing contained in the German MG42 armorer's repair manual (available for $28), the firing pin protrusion is to be between 1.35 (min) and 1.65 (max) millimeters.

[mtnlvr]

I do see the 1.35mm min spec on page 65 of your translated HDv 181/7, but for whatever reason, I can't seem to find the gauge drawing. I bought a few of your translations a couple of years back. I'm still waiting for you to do a semi auto armorer's manual. Lol.

The manual also mentions shortening the rear of the firing pin to correct protrusion. That's just for the full auto pin right? For the semi would I shorten the front?

[JBaum]

The plan drawing for making the firing pin protrusion gauge is at the bottom of page 20 of HDv 181/7

I'm not familiar with the semi setup, so I can't say how shortening the firing pin should be accomplished.

[mtnlvr]

Ahh, I see it now. Hidden in plain sight.

John, thanks for your contributions here and everywhere else to keep these guns running!