If you're running a gun without a metal chamber, you're probably going to have a bad time (unless it's a very small caliber such as .22LR). I would argue that i

If you're running a gun without a metal chamber, you're probably going to have a bad time (unless it's a very small caliber such as .22LR). I would argue that if you're going to require metal in a gun at all, might as well require it to be the chamber to prevent catastrophic failures.