Gass relief hole botom of breech block.

[HisSoldier]

You may have missed the fact that the 1970s Mausers have gone up in price and are being collected.

I did the operation to two P-08's, the first was a 9MM 1970's 4" barreled beauty which only had one flaw for me as a shooter (this was many years ago) I cut the grip safety off and modified the safety to function normally, without the grip safety pinching my hand. I have no particular dislike for grip safeties and like them in all my 1911's, but the Mauser GS was very poorly designed IMO. After modding the safety to act as a normal safety I filled the slot at the back of the grip panel with wood my GS gave me and he checkered the plug so it wouldn't show.
So, that Mauser is not a collector, it's a shooter. The other Mauser I have is a 6" barreled 7.65 MM, in new condition and I think never fired from the factory, so, since I don't shoot it I decided to not alter it.
The other P-08 I altered is a 1920 commercial which has matching numbers but not a matching magazine, it's 6.35 MM and shoots nicely, and it also looks near new. I figure without a matching magazine it's not highly valuable either.

The fourth P-08 is also a DWM 1920 Commercial WITH matching magazine, in 6.35 MM again of course, and it also is in very pristine condition, even better than the other one, I decided to leave it alone and don't shoot either it or the 7" 1970 Mauser, so, since I don't shoot them I see no possibility of a pierced primer causing bolt damage.

I hope vaseline will not be part of the decision

What is that supposed to mean Vlim? Is that something you are familiar with using somehow in your guns? Must be a European thing.

But back to the 1970's Mauser firing pins, yes, they have shallow grooves that go all the way to the back of the FP, but why they put them there is a mystery I guess, though I think they would bleed enough gas back past the pin to prevent the damage, so I did probably drill the 9MM gun's block without good cause.
But again, it's probably not a collector anyway and does no harm IMO. I originally was going to drill all four breech blocks but based on the opinions here about hurting value I decided to not do it to the two that may have some slight collector appeal, and we all know, guns that aren't that collectable today sometimes become so tomorrow.