I'm not sure what S&W policy is, but after 3 returns I would start insisting on a new gun. The vast majority of them run right out of the box without incident. If they can't figure out how to fix the gun (and properly test it before returning it) it's time to step up and make it right.
Thats pretty much what I think. The customer service guy I spoke with this morning must have had a really bad weekend. He is the only SW employee that has been short/rude to me. He raised his voice and all he would say is I'LL SEND YOU A RETURN LABEL. He didn't want to spend any time listening to a description of the problem. He just added fuel to my fire. I have been nothing but polite to all the folks I've spoken to. I spent 30 years tracking down intermittent problems and know they are difficult. I am going to call tomorrow and speak to someone else. My thought is if one of SW sponsored pros was having this problem, would it take them 4 times to fix the gun? I think NOT. Surely they have someone in their pro shop who knows the cure for the problem. Either they get the gun to someone who knows how to fix it or give me a new one.