XM913 chain gun
The XM913 is an experimental American chain gun produced at Picatinny Arsenal. The cannon is a larger and more modern version of the 25 mm Bushmaster cannon. Although its shells, 50 x 228 mm, are twice the diameter of the 25×137mm M242 Bushmaster, the 50mm cannon is not much longer than the smaller weapon. The overall lengths of the 25mm cannon and 50mm cannon are and , respectively; while the portion of the gun that intrudes into the turret are and , respectively. Ammunition The XM1204 High Explosive Air Bursting with Trace round is programmable. The gunner can select from three detonation modes. When in point detonate mode the projectile's high explosive detonates when it hits a target. In point detonate delay mode the high explosive detonates a brief instant after it hits a target. The delay is intended to let the projectile first penetrate a wall, and explode when it emerges on the other side. In air burst mode the cannon's aiming system programs the munition to explode in the air above the target. When the gunner aims his or her sight on the desired target, and presses their trigger halfway, the aiming system calculates the range to the