Will a G19 Gen 4 MOS slide fit and function on a G23 3rd Gen frame?

No because the cut in frame is different for the recoil assembly.

Darn!

I can't remember if I was trying to put a gen 3 slide on a gen 4 frame or vice versa.
BAD IDEA.

Gun locked up out of battery and I had to call someone to 'pull down on this while I pull on this' type of thing.


edit to add - this was as I was getting ready to walk out the door for a GSSF shoot. I thought, "Great, I just fooked two of my entries." You are such a dumbass! was screaming in my head over and over until I got them separated.