So - I go shooting with my buddy. Good little setup. I load 9mm lead bullets and 223s. Go to the spot start shooting.....all my 9mm feed great in my Glock 19 and Canik....but he puts them in his Glock 19x and wham! They lock it up.....twice. My ARs shoot all my bullets I reloaded fine - about 600 of them....and he can't get them to feed right in his ARs. I did case gauge checks, they are fine. Maybe cleanliness of the guns (mine are always cleaned and lubed) Magazines? Not sure. Any ideas??