I spoke with US Fire Arms today and the official line was "no", don't shoot .45 ACP +P out of the .45 ACP cylinder as it will void the warranty. That was the legal answer I got. From an engineering standpoint, it should hold up, but will put more wear and tear on the gun as one might expect. I have noticed too that .45 ACP out of a SAA type gun is not a light wadcutter recoil either, but easier for me to hit with better accuracy than standard loaded .45 Colt. In a double action gun like a S&W 625, it is a pussy cat compared to other big bore rounds, but then again the 625 has nice recoil absorbing Hogue rubber grips.