"Reverse Pump" - a new locked breech mechanism concept

A firearm mechanism I came up with. Sliding chamber, stationary breech, meant for straight walled cartridge.
Designed with manufacture simplicity in mind, this can be done with minimal tooling and limited resource.
Test load used in this video order were 0.83, 2.49 and 1.66 centimeter cubic of black powder respectively. Each shell contains 10x8mm steel ball bearing

Reverse Pump is a work in progress. I'm still working on pistol grip, magazine and feeding mechanism.