November 25, 2007: German CH-53G transport helicopters in Afghanistan are having their armament (currently two 7.62mm machine guns, mounted on the side doors), increased with a .50 caliber (12.7mm) machine gun on the rear cargo ramp. The U.S. Navy and Marines first developed this system three years ago, calling it the GAU-21. The larger caliber machine-gun provides more effective firepower when dealing with ambush situations, or anyone on the ground firing at you. The Germans also plan to replace the door guns with 12.7mm machine-guns.

The GAU-21 uses a Belgian M2M .50 caliber machinegun, instead of the U.S. made M2. That's because the M2M has less recoil and fewer malfunctions (cook offs). The M2M also has longer barrel life. U.S. helicopters also use the M2M as door guns.