Replacement would be the fix is the chamber is reamed too deeply, as suggested by Vauquero in #15. Others have suggested a longer firing pin which was my first thought.
The other side of your idea is “does the bolt fully close”?
Possibly. Yours could be very slightly out-of-battery. Does the rifle fire at all? Does it never fire and just ding the primer?
In reverse order.
It NEVER fires. And thus could be out of battery. On a 336, I would think a bolt not fully closing, that points me to a worn or mis-shapen finger lever tip. But D@amn, you’d have to really abuse a rifle to wear out a finger lever tip.
A longer firing pin makes sense, but I’d rather fix the ‘why’ of what calls for a longer firing pin.
Probably weak hammer spring. A heavier hammer spring will probably help. My politically incorrect (and I KNOW the safety nazis will salivatingly knee-jerk in Pavlovian fashion over this) solution is that I replaced all the marlin lever guns’ that I own’s two piece firing pins with one piece ones. No more light primer strikes and the lever safety tab works as intended and is more than adaquate. (I got rid of the uselss cross bolt safety a long time ago). The very best safety is the one between a shooters ears.