Just recieved this reply from Bullberry.
As for 321 Bullberry . . . it is otherwise known as the 321 Bullschuetzen. Fred made them prominently for the Schuetzenfest games. I would guess that it is a pistol length barrel, as they were generally made at (I think) 15" for the game. Fred used to compete in and sponsor a lot of the games back in the 90's. The cartridge is a dramatically shortened 32-40 blown out to accept a true .321 cast bullet.
Safe shooting
Doug