Thank you guys for all the responses, I really appreciate it. As for the ammo, only brass, I do not use steal cased. The punched primers seem to happen on 5.56 ammo, and yes my barrel is 5.56 caliber. I've been shooting 5.56 ammo with this rifle for 5+ years, with the problem just beginning this past year. I took it to a local gunsmith here in Charlotte, where a good friend of mine works. They inspected it and surmised it was a headspacing issue. When I returned it to Smith and Wesson the first time, I was informed that the rifle was having NO issues. I just returned the rifle again to Smith and Wesson, they have inspected it, and again see no issues with the rifle. I will purchase a new firing pin to see if this resolves the issue. Thank you again guys for all of the feedback.