So here's an issue I am having with a first gen G17. This is my beater, It was my first handgun as a kid, probably 10,000+ rounds through it so far. After the last shot in a mag, the slide doesn't lock to the rear. I've never had any issues and this just started happening. - All 20 of my 17rd mags do the same thing - if you insert an empty mag, and rack the slide manually, it locks to the rear (on all 20 mags as well). - I tried 5 different types of ammo. Any thoughts?