m777M777 is the world's first 155mm Howitzer wehing less than 10000 lbs (4218 kg). Selected by the U.S. Marine Corps and U.S. Army as their next generation MediumM777 HOWITZER. U.S. Army soldiers make final preparations to a M777 155mm Howitzer before conducting a fire mission at Camp Taji, Iraq, Jan. 2, 2008.