Six 105mm recoilless rifles, armor, and a six-cylinder truck engine combined to make the M50 Ontos one of the most lethal light fighting vehicles ever designed. Rejected by the US Army, it nevertheless found a home with the US Marine Corps which appreciated its combination of power and resilience. Throughout the Vietnam War, the Corps used the Ontos to break enemy hard points, disperse attacks on bases, and take out opposing light vehicles.