Designed entirely in TinkerCad.
I designed it to use 2 N20 motors (probably 600rpm) which hopefully should be held in place with the motor mounts in the chassis.
Uses a malenki nano ESC. But will probably fit a BBB Dual ESC, might need to shave off a few grams for that though.
The motor mount is designed for a BE1806 2300kv Brushless Motor.
The drum has a space for a 3mm bearing on one side while the motor should be press fit into the other side. The drum should be held in place with an M3 12mm bolt and M3 nut.
Build this at your own risk, I haven't even tested it with a weapon yet. This is a work in progress.