In my experience if its Bronze (and there are different alloys) its not going to bend no matter what you do. It will likely break first. I have annealed a lot of brass parts, and cartridge cases and quenched them. Brass will not crack. Bronze, the gun metal alloy, is wonderful for ML cannon barrels for example, but is stinks as a BP or other ML gun part. All the Union artillery pieces used in the our War Between the States had a failure rate in service, except the smoothbore bronze guns. So if you want a “brass barreled” gun make sure you get a “Gun Metal Bronze” alloy NOT BRASS.