March 16,2008: An automatic, laser controlled, airburst shell has been developed for the Mk44 30mm Bushmaster automatic cannon. The basic Mk44 weighs 344 pounds and fires at a rate of 200 rounds per minute (up to 4 per second). The 30mm Bushmaster has 160 rounds available, before needing a reload. That means the gunner has 40-50 seconds worth of ammo. Each 30mm round weighs about 25 ounces (depending on type.) Explosive anti-personnel rounds are the most common round used in the Mk44. The new airburst option uses a dual loading system, so the gunner need only flip a switch to select the airburst ammo, or other ammo (either armor piercing, or "dumb" explosive shells). The smart shells require the gunner to use the laser range finder, built into the fire control system, to select the range at which the smart shells will explode. So the drill is, select ammo, use laser to select range of detonation, then fire (either single shells or a burst of automatic fire.) The laser guided shells can penetrate up to 8 inches of concrete, and still detonate on the other side. You can fire a few rounds through a window, where the shells will explode, providing the same effect as throwing a grenade into room. Same deal with enemy troops taking cover in a trench or behind any solid object (rocks, or a mound of dirt). The new airburst round has been undergoing field tests for over a year, and the U.S. Army and Marine Corps are planning to install it in their new armored vehicles. The U.S. Air Force will upgrade the Mk44 cannon they are already installing in their AC-130 gunships.