The M44 Spartan IFV(H) is a heavily armored fully tracked combat fighting vehicle (as stated in the formal manual). It has the same chassis of the new M28A1 with the turret of the M22 Marder wheeled IFV. The M44A1 is armed with a high-velocity M17 30mm autocannon with a maximum rate of fire of 650-700 rpm, and a sustained rate of fire of 250 rpm. The M17 can fire all standard rounds including sabot and air burst rounds. The M44A1 has a crew of three: a driver, a gunner, and a commander. The gun is belt-fed and is automatically reloaded when the belt is run dry. The engines are the same as the standard M28. The entire XM44 program stemmed from the success of the Paternian Guardian II IFV based on the M23 Chariot MBT.