I recently got a gen 2 19 in a trade from a co worker. I have known this guy for a long time and he carries way more than he shoots. I was preparing for a range trip tomorrow and was hand cycling some aluminum cased ammo through the gun. (Safe direction in rural back yard). I wanted to see how worn the magazine springs were in the three mags he provided. I discovered a disturbing issue. The round would chamber, but upon extraction the round would only come out of the chamber half way and the entire slide would seize up to the extent that it was impossible to retract to ejection. Is this an issue with the extractor? Or the ammo? I noticed that it didn't appear to have the same issue with brass cased ammo, and it didn't happen in my gen 3 19. I am confused. Thoughts? I should also note that I do believe that the weapon has had the parts upgrade.

Can't answer your question, but i sent both of mine to Glock to have them rebuilt.   For free.

Back in 1991 when I got my first Glock 19, I had a bad time with baler aluminum ammo. Brass was perfect. In recent years, I noticed that the Gen 3a I have will feed aluminum with no problem. My brother still has his Glock 17 from 1990 and he had the same issue to with  blazer ammo. I often contributed it to maybe small changes made and also the cut from 90 to 15 degrees on the ejection port.
That could be the case, but not sure. All my Gen 3'A feed everything flawless.

I can hand cycle some of my pistol as fast and hard as I can and still get fte's. Shoot it and see what happens.

Like everyone said, shoot it and see what it does.

My gen 2 police trade in 17 will feed, shoot, and eject aluminum, brass, and steel case with no issues.

Thanks for the replies. Got to the range today and it ran like a top. Guess I got worked up over nothing. Case closed.