Shillelagh missile

MGM-51 Shillelagh
MGM-51 Shillelagh
Type	Surface-to-surface missile
Place of origin	United States
Production history
Manufacturer	Aeronutronic, Martin Marietta
Unit cost	from $1938 to $4052
Produced	88 194 from 1964 to 1971
Specifications
Weight	MGM-51A : 59.1 lb (26.8 kg) MGM-51B/C:61.3 lb (27.8 kg)
Length	MGM-51A : 3 feet 7.7 inches (1.110 m) MGM-51B/C: 3 feet 9.4 inches (1.153 m)
Diameter	6 inches (150 mm)
Warhead	15 pounds (6.8 kg) Shaped Charge Warhead including 8 pounds (3.6 kg) of Octol Explosives able to defeat 15.5 inches (390 mm) of RHA at 0° obliquity
Detonation mechanism	detonated on impact
Engine	Amoco Chemicals Hercules solid-fuel rocket
Wingspan	11.5 inches (290 mm)
Operational range	MGM-51A :6,600 ft (2,000 m) MGM-51B/C :10,000 ft (3,000 m)
Speed	1,060 feet per second (320 m/s)
Guidance system	Infra-red signal link
Launch platform	Tank (M551 Sheridan and M60A2)

15 pounds (6.8 kg) Shaped Charge Warhead including 8 pounds (3.6 kg) of Octol Explosives

The Ford MGM-51 Shillelagh was an American anti-tank guided missile designed to be launched from a conventional gun (cannon). It was originally intended to be the medium-range portion of a short, medium, and long-range system for armored fighting vehicles in the 1960s and '70s to defeat future armor without an excessively large gun. Developing a system that could fire both shells and missiles reliably proved complex and largely unworkable. It served most notably as a primary weapon of the M551 Sheridan light tank, but the missile system was not issued to units serving in Vietnam. Ultimately very few of the 88,000 rounds produced were ever fired in combat.

Shillelagh was considered equal to the later BGM-71 TOW anti-tank wire-guided missile first produced in 1970 by the U.S, which could not be fired from the gun but had a simpler guidance system. However main battle tanks of the late 20th century fielded improved conventional 100 to 125 mm guns and ammunition which proved effective against enemy armor threats. While Soviets designers have developed gun launched missiles, the US and NATO were developing guided tank shells.

The name of the system is that of a traditional wooden club from Ireland.

With the rapid increase in armor thickness during World War II, tanks were becoming increasingly able to survive rounds fired from even the largest of World War II-era anti-tank guns. A new generation of guns, notably the British 105 mm Royal Ordnance L7, were able to cope with newer tanks, but it appeared that in another generation the guns needed would be too large to be practical.

To overcome this potential difficulty the US Army began to favor high-explosive antitank (HEAT), or shaped charge rounds in the 1950s. A shaped charge's penetration is not dependent on the speed of the round, allowing rounds to be fired at much lower velocities, and thus from much lighter guns. They also work better at larger diameters, and a large-diameter low-velocity gun makes for an excellent assault gun that can be mounted on light or medium-weight vehicles. However, the low speed of the round makes it hard to aim over longer distances. The US Army sought to overcome this problem by developing guided missiles with shaped charge warheads that were accurate beyond a few hundred yards.