1937 Mauser Luger (S/42)

[LugerMan.com]

While the sear bar reset can be problematic ...
if there is a strike on the primer , then means the sear is resetting.

First 'd take the gun apart and clean the breach block from the inside.

2nd I'd inspect the firing pin and sear for any wear and damage, as if it is somewhat bent or worn, it can be creating abstraction for firing pin as it moves forward, ans slows down the strike itself, resulting in the unreliable firing.

3ed, i'd check the head spacing just for the hell of it, as it may also result in unreliable strike.
if rounds move forward as a result of the firing pin strike, some may fire some may leave a mark but not fire.

4th, I'd replace the firing pin spring and main spring , just to make gun safer to fire and more reliable.

5th, the firing pin may be shortened or broken or worked on, that may also create the problem.
at that pint a pencil test is in order.

6th use good ammo ( Winchester, Federal, Foicci , Remington ) in that order.


There are different courses of action, depending on what you find going from step to step.

Thanks.