This video shows Groot Mamba, a reader of the blog, rapidly firing the NTW 20mm rifle. Groot is firing the 20X82mm round, which is, in a sense, a “20mm Short” round. When firing a projectile that can carry a high explosive warhead, kinetic energy is not necessarily required against soft targets because energy can be delivered with the chemical payload – hence the lower powered cartridge.

Groot says that the larger, and more common, 20x110mm round is nicer to fire because the muzzle brake is more effective.