Well, I finally got out to my favorite shooting spot in the woods to crack off a few rounds of .45 Super in my 21SF. The first round of 13gr. of AA#7 was awesome. It laid out a milk jug I had filled with water like a magnum revolver or a 10mm round. Then, the unexpected happened. I looked down and the mag. was on the ground. I thought that might be an isolated time. Put mag back in and it did it again. I had some lower loads of AA#7 and Blue Dot and it did it with those, too. Also some +P stuff, too I thought it might be the mag. So I changed that out, still did it some more again. Even did it when I shot some standard velocity .45ACP rounds. I had my LWD stock length barrel and the SS non-captured guide rod along with the 22lb. ISMI recoil spring, which did great. My 21SF has the ambi mag. release on it. I'm thinking that might be it, since I've heard similar stories from others here that have the mags. dropping out of the gun unexpectedly with an ambi mag. release gun. Should I get a stronger mag. release spring? Should I or a Glock armorer or Glock change this gun's ambi mag. release back to the standard non-ambi type? Can I still use the same mags. I have now if I do that? What are some of the solutions that some of you have found. It is pretty disconcerting to fire off a round and your mag. drops out of the well to the ground or drops down and is out of action. Thanks.