I have used it in several of my 5" guns and my Lightweight OACP. The OACP showed the biggest difference in felt recoil and recovery time between shots. It made a dramatic difference that I wouldn't have believed if I hadn't experienced it. That EGW flat bottomed firing pin stop is a must-have for running a hot 10mm on the 1911 platform. I just converted a Kimber Stainless Compact from .40 S&W to 10mm. If not for the EGW firing pin stop and a 25 pound mainspring (not recoil spring), I wouldn't have been able to pull it off. Great product. Five stars.