Northrop Grumman 30mm Bushmaster Mark 44 autocannon
The Northrop Grumman 30mm Bushmaster Mark 44 autocannon is an improved version of Northrup Grumman's M242 Bushmaster autocannon.
Like its predecessor the new weapon is a "chain gun", which means it does not use the explosion of the previous round to cycle a new cartridge into its firing chamber. Rather an external motor cycles the gun. This gives the gunner finer control over the rate of fire, and it means that misfires do not cause the gun to stop and require manual clearage of the breach.
The M242 was introduced in the 1970s, and was used to arm the Bradley Fighting Vehicle, and a variety of other armored vehicles. The M242 fires 25 mm ammunition, whil the mark 44 fires 30 mm ammunition. Its ammunition is not only more powerful, but it can fire types of advanced rounds, not available for the older weapon. In particular, it can fire high explosives designed to spray shrapnel at a precise distance, allowing the gunner to target enemies who are behind cover. He uses his optics to get the distance to the wall, and electronics within the projectile is instructed to explode just beyond that distance. He then fires over or beside the cover the enemy is using.