M102 howitzer

M102 howitzer
The M102 howitzer firing
Type	Howitzer
Place of origin	United States
Service history
In service	1964–present
Used by	USA  Brazil  Turkey  Philippines  Khmer Republic  Saudi Arabia  South Korea  South Vietnam  Belgium
Wars	Vietnam War, Invasion of Grenada, Gulf War, Iraq War
Production history
Designed	1962
Manufacturer	Rock Island Arsenal
Specifications
Weight	1,496 kg (3,298 lb)
Length	Travel: 5.18 m (20 ft)
Barrel length	32 calibres
Width	Travel: 1.96 m (6 ft 5 in)
Height	Travel: 1.59 m (5 ft 3 in)
Crew	8
Shell	105×372R
Caliber	105 mm (4.1 in)
Action	vertical sliding-wedge
Recoil	hydropneumatic
Carriage	box-trail
Elevation	−5° to +75°
Traverse	360°
Rate of fire	Maximum: 10 rpm Normal: 3 rpm
Effective firing range	11.5 km (7.1 miles)
Maximum firing range	15.1 km (9.4 miles) with rocket-assisted projectile

The M102 was a light-towed 105 mm howitzer used by the United States Army in the Vietnam War, the First Gulf War, and the Iraq War.

The M102 105 mm howitzer is used in air mobile (helicopter), attack plane, and light infantry operations. The weapon carriage is lightweight welded aluminum, mounted on a variable recoil mechanism. The weapon is manually loaded and positioned, and can be towed by a 2-ton truck or High Mobility Multipurpose Wheeled Vehicle (HMMWV), can be transported by UH-60 Black Hawk helicopters, or can be dropped by parachute with airborne units. When emplaced, the howitzer's high volume of fire compensates in large measure for the lower explosive weight of the projectile compared to the Army's 155 mm and 8-inch howitzers. Since 1964, the Army acquired 1,150 M102 towed howitzers. The weapon is being replaced by the M119-series 105 mm howitzer.

Units were initially equipped with the M101A1 howitzer, virtually the same 105 mm howitzer that had been used to support U.S. forces since World War II. In 1966 a new 105 mm towed howitzer, the M102, was received in Vietnam. The first M102s were issued to the 1st Battalion, 21st Field Artillery, in March 1966. Replacement of the old howitzers continued steadily over the next four years.

Many of the more seasoned artillerymen did not want the old cannon replaced. Over the years they had become familiar with its every detail and were confident that it would not disappoint them in the clutch. These experienced artillerymen could offer some seemingly convincing reasons why the M101 was still the superior weapon: its waist-high breech made it easier to load; it had higher ground clearance when in tow; but most important, it was considerably less expensive than the M102. Their arguments, however, were futile.

The new M102 was substantially lighter, weighing little more than 1½ tons whereas the M101A1 weighed approximately 2½ tons; as a result, more ammunition could be carried during heliborne operations, and a 3/4-ton truck rather than a 2½-ton truck was its prime mover for ground operations. Another major advantage of the M102 was that it could be traversed a full 6,400 mils; the M101A1 had a limited on-carriage traverse, which required its trails (stabilizing legs) to be shifted if further traverse was necessary. The M102 fires the same semi-fixed ammunition as the M101, but its longer barrel (32 calibres versus 22 calibres on M101) allows a slightly higher muzzle velocity and thus enhanced firing range. A low silhouette made the new weapon a more difficult target for the enemy, an advantage that far outweighed the disadvantage of being somewhat less convenient to load.