The Denel Vektor GA-1 is an automatic cannon based on the German WWII MG 151/20 automatic cannon. Compared to other rapid-fire 20 mm autocannons, it is lightweight and has low recoil due to its design and the use of the 20ÃÂ82mm cartridge. The weapon was intended for use in vehicles, naval vessels, and helicopters. One gun was fitted to the Atlas XH-1 Alpha attack helicopter demonstrator.