Ive put about 500 rounds through my saint and no issues. I have noticed of the two ammo types I have put through it the 55 grain fmjbt seems to group better than the 55 grain fmj. Both x-tac rounds from pmc. I am wanting to get some bulk and I think the heavier I get I might get even tighter (not that it really matters) and just wanted to know what you guys are finding. If not with this same gun at least an AR M4gery with a 1/8 twist. Any experience you have please share!