I have had 3 types of mags to use in my STI Lawman .45 over the last break in period and one match. They all worked well. The ACT mag I got with my gun (STI on it). looks like a wilson mag with the same type of bumper pad. It has a steel follower. Works just as well as the others (WIlson, CMC). WHat I like about the wilson and Cmc is they have a little bit of give when inserting them for a mag change. The ACT /STI mag has a stronger spring. What I don't like about the CMC is the follower that came on mine...very narrow, slippery. I think I would be GTG using STI mags. I found no issue at all withthem. They all worked. The STI LAwman in .45 acp feeds better than my sti Edge used to.