I had same question, I have a SIG SRD556, the opening through the baffles is about .310 @ smallest point. Wanted to build a 6x223 or 6ARC. So I called SIG tech support, response was "No way, only 223, we make other cans", which I'm certain is the CYA response. I understand there are limitations as to pressure & gas volume, so would not try mine with a 22-250 or a 6.5 Creedmore.