My son recently picked up a decent K-22 of approximately 1946 or 47 vintage, lots of holster wear but mechanically good, with the exception of a tiny bit of cylinder end shake. I didn't get a chance to check it out before he bought it.

It's having an occasional misfire with multiple ammo types and brands (even the match stuff). The mainspring looks to be original as does the screw. I've tried to tighten the mainspring screw but it appears to be down tight. The firing pin is protruding well enough seems a little loose in the bushing.

I'm hesitant to use Power end shake washers so am asking for advice as to the best method to correct.