room for movement. The Army further tested a full-size Vulcan cannon firing out the door of a UH-1. It was capable of firing 2400 rounds per minute, or about 40 rounds per second. Despite this being a significant reduction from the nearly 100 rounds per second fired by a standard Vulcan cannon, the installation proved "too kinetic" for the UH-1. Podded versions of the M24 20 mm cannon were tested in combat over Vietnam. There was a wide variety of 7.62 mm automatic weapons tested, including different installations of the M60 machine gun. AS-10 and SS-11 missiles were tested in several different configurations. High-capacity rocket launchers were also tested, such as the XM3 launcher, which had 24 launching tubes. Press photos were taken with the XM5 and XM3 installed on the same aircraft, but this arrangement could not be used because it was more than the gross take-off weight of the aircraft. During the Easter Offensive of 1972 by North Vietnam, experimental models of the TOW-firing XM26 were taken out of storage and sent to South Vietnam in response to the onslaught. The pilots had never fired a TOW missile before, and were given brief crash courses. Despite having little training with the units, the pilots managed to hit targets with 151 of the 162 missiles fired in combat, including a pair of tanks. The airborne TOW launchers were known as "Hawks Claws" and were based at Camp Holloway. During the conflict, 7,013 UH-1s served in Vietnam and of these 3,305 were destroyed. In total, 1,151 pilots were killed, along with 1,231 other crew members (these figures are not including Army of the Republic of Vietnam losses). Post Vietnam, the US Army continued to operate large numbers of Iroquois; they would see further combat during the US invasion of Grenada in 1983, the US invasion of Panama in 1989, and the Gulf War in 1991. In the latter conflict, in excess of 400 Iroquois performed a variety of missions in the region; over a nine-month period, the fleet cumulatively reached 31,000 flight hours and achieved a stable fully mission capable rate of 70%. The type comprised more than 20% of all rotorcraft across the coalition and recorded 21% of the overall flying hours. Even after the Gulf War, the US Army had more than 2,800 Iroquois in its inventory; in particular, 389 UH-1Vs comprised 76% of the Army's medevac aircraft.