Do note that upon the introduction of the fold crimp, just prior to WWII the British began experiments with shells longer than the chamber. They were mostly halted by the war but resumed immediately afterward. From that point onward virtually all British 12 gauge shells marked as suitable for 2˝" chambered guns were actually put up in a longer hull.
Bell brought this to the attention of a lot of shooters, but to be totally correct in giving credit where credit is due, he neither Discovered it nor Invented it. This fact had been long settled likely before Bell ever pulled his first trigger.
I don't know just how old Bell is but in less than a month I'll be 81 & this was all "Laid to Rest" before I turned 12.
Do note a couple or three things though.
No shell should be fired in a chamber in which the loaded shell has to be pushed into the cone, it is essential there is clearance between the end of the loaded shell & the cone to allow proper opening of the crimp without restriction.
Also no shell longer than the chamber should be fired in a chamber having a step or extremely short cone which lets the end of the shell actually lap into the bore itself. It may or may not burst the chamber but is certain to increase the pressure drastically.
Finally, the longer shell should only be loaded to the pressure level the gun was designed for. This harks back to Rocketman's warning.
