I've had nothing but superb customer service from Sig in the 4 times I've called them. On two occasions, (one a used gun and the other new and I told them the used gun was "used") they paid for the shipping both ways and comped the service bill. If I were you, I'd call them and ask your questions. The guys I've talked to on the phone were knowledgable and very polite. That said, I'd make sure the firing pin race is absolutely clean and free of oil and grease. BTW, I've never filled out a warranty card. YMMV, Rod