I'll hit you with something no one has mentioned. Are all of the screws tight?
I have an 1895 Marlin. I noticed that if it is shot much many things loosen up. Make certain that all of the screws are tight. I put blue Loctite on about everything after a turn like yours. Check first to see if the screw on the underside of the action, up by the forearm, is tight. If this is loose even with the bolt locked the action stretches out.
Ergo, light firing pin hits. CHECK it out.
