Any parts needed, Numrichs has them, I have 25 years bench exeprience as a gunsmith. I have had several of these guns do the same thing described over the years, 90% of the time, there is a small sliver of wood, worked loose and impeding the parts from working correctly, I.E., the splinter is between the hammer and firing pin, slowing down the strike, or like the other posts said, gunk inside. Take the stock off and brush all working parts with a toothbrush and Hoppes #9, or spray with a penetrating oil, let stand a few minutes, the spray out the parts with gunk out, re oil where needed. Lots of times this is also the culprit.