Last week, a customer brought in his GEN 4 G19 because of reliability issues. The big one was the fact that the brass was hitting him in the face.
Always liking a challenge, I said I would help. The first thing I did was field strip the gun. As I did this, I noticed HUGE chunks of brass shavings everywhere. The gun probably had less than 500-700rds through it. The majority of the ammo shot was Winchester Value Pak.
Pics of what I pulled out of this gun:
While everything was apart, I saw that there were a lot of jagged edges on the plunger and striker. So I took a hard stone and cleaned them all up and rounded and polished the plunger.
Hard lines on the striker side where it is rubbing on the channel slot.
Cleaned up and polished!
Put the gun back together and shot several hundred rounds through the gun. No more brass in the face! Amazing what cleaning large chunks of brass out of the gun will do.
Next problem Glock. Buddy of mine brought in his GEN 2 G19 because of brass hitting him in the face. Like above, field stripped it and got it ready to go in the ultra sonic and what did I found? Tons of crud in EVERYTHING. It was so much that I just had to take a pic!
Cleaned everything up and shot it. No more brass to the face!
As we know (or should know), the extractor on the Glock is just BARELY making contact with the rim (as is) so anything that changes how much tension or contact there is (like brass shavings or dirt) has a big impact on it. So if your Glock is throwing brass in your face (no matter if it is a GEN1 or GEN4) make sure to pull everything out of it and clean it well.