I've been tryin to learn more about the lesser popular Glock models and I haven't even seen the .45 GAP in guns shops or even seen the ammo! At least where i live. I think it's basically a short .45 Auto right? Are they really popular enough to justify Glock making all 3 model sizes? Same thing with the .357 Sig All I ever hear about is 9mm, .40 S&W, .45 Auto and occasionally the 10mm. Just curious! Feedback welcome! Thanks!