I took my full size 9mm out yesterday and I had the slide slam forward when I inserted a new mag several times. I was using WWB with 17 mags. So I'd shoot one mag, eject it, put a new mag in the slide would slam forward when the mag seated without me touching the slide release. It didn't do this when I inserted the mag gently but when I inserted the mag with a little force the slide would slam shut with my thumb nowhere near the release. I guess I never considered it, but is it suppose to do that when you put a new mag in with some force behind it?