Demolition Ranch puts some stank on it for science:
Potato potAHTO.. 9mm.. .308…. .40.. 9mm.. tomato tomAHto. LOL that bulged 9mm shell that was in the .40 chamber… epic, it looks like a loudener. I wonder how straight that bullet was flying considering it wouldn’t have engaged any of the rifling. Probably would have keyholed like hot garbage.
The .223 Glock 23 was an awesome idea… too bad the results were less than amazing. I wonder if you put some sort of sleeved insert in the barrel before loading the .223 round if a person could make it work any better? I know they make inserts for shotguns to fire rounds like .22 LR and what not… I’m just thinking out loud here. I don’t know enough about chamber pressures in order to confidently attempt something like this without blowing my guns up.