Thompson Autorifle

On the negative side, the Autorifle required lubricated ammunition for proper functioning and the ejection of spent cartridge casings was so violent as to be hazardous to bystanders.

[1] For reloading, the Thompson Autorifle uses an interrupted screw delayed blowback operation where the bolt has 85° angled interrupted rear locking lugs that have to overcome a rotation of 110° ( 90° to unlock before the angle blend of 70°/40° and 6°) that delays the action until the gas pressure drops to a safe level to eject.

[3] The weapon was an improved derivative of the Thompson Autorifle that could be operated manually if the two curved 'shutters' around the bolt head are moved into the down position.

Surviving examples suggest there were Rifle and Light Machine Gun variants and 6 of both types were manufactured.

The BSA Autorifle is a delayed blowback–operated rifle chambered in the .303 British round and fed from a removable 10-round box magazine.

Much like its predecessor, it uses a bolt with 85° angled threads delayed by a 90° twist to unlock from a bronze nut until the gas pressure drops to a safe level to eject.