I have been running wolf military classic (reg black box grey case wolf has more issues), silver bear, brown bear, golden bear in ar's my 556 and ak's for a pretty long time. The bears are are better quality as far as cleaner and less ftf etc. Silver and golden do not take the lacquer bath like the brown does. But some silver and golden have the sealant around the primers which some shooters remove. Bottom line is that I have had a handful of ftf over a long period of time and no explosions, rim ripping off etc. I am not saying that it can't happen, anything can happen with any ammo. A friend had a black hills 68gr hp blue box round blow the crap out of his ar-15 along with his arm and hand, and that is good ammo. He called them up and they basically said "look at the back of the box, no guarantee, it's remanufactured". He also told them upon further inspection of the remaining rounds some had pretty decent dents all over, black hills said politely "read the back of the box, sorry". But, using steel cases in a sig 556 will take more of the finish off where the cases hit after ejecting. I definitely recommend putting a piece of velcro or something where the shell will hits. Bottom line is, everyone has a preference.