The 60mm mortar was a versatile weapon organic to the Marine rifle company. It was sometimes called the company commander's "hip pocket artillery" because the mortar section was always available for fire support. Providing high angle fire, the 60mm mortar was an important part of the company's firepower in both offensive and defensive combat. It was ideal for for engaging targets in ravines, reverse slope positions, and in other defiladed positions. The weapon was used extensively by Pfc. Eugene Sledge and Cpl. Merriel Shelton
Usage by MarinesEdit
The 60mm mortar was developed by the US Army Ordnance Department. It gave the infantry an indirect fire weapon to span the gap between hand grenades and the 81mm mortar. Testing took place in the late 1930s, and the first order for 1,500 M2 mortars was placed in January, 1940. During World War II, more than 60,000 M2 mortars were produced by the Read Machinery Co., Kennedy–Van Saun, and the Firestone Tire and Rubber Company.
Until May 1944, the mortar section fell under the rifle company's weapons platoon. Under Table of Organization F-1, approved in May 1944, the weapons platoon was eliminated. When this happened, the mortar section was moved under administrative control of the company's headquarters section. In combat, it operated under the direct control of the rifle company commander.
The mortar squad leader was a corporal. He carried the M4 sight when the squad was on the move. The other Marines in the squad were non-rates. The gunner carried the complete mortar. The assistant gunner carried the aiming stakes. Three ammunition bearers were tasked with carrying mortar rounds, usually in the M2 ammunition vest.
Several types of ammunition were available for the M2 mortar. The primary round was the M49A2 high explosive round, which weighed about 3 pounds. It had a point detonating fuze and a bursting radius of about 17 yards. The M83 illuminating round was a parachute flare that weighed about 3.5 pounds. It generated about 11,000 candlepower and had a burn time of 25 seconds. The final type of ammunition was the M302 white phosphorous round. This was used both for screening, and as an incendiary round. It was not introduced into service until the very end of the war. Target practice, and drill rounds were also available for training.
Like all weapons, the 60mm had strong points and weaknesses. A well trained mortar section could lay down a barrage of almost 100 rounds in a minute. As part of the rifle company's final protective fires, for example, this produced devastating results against Japanese banzai charges. But in heavy jungles, mortars were sometimes useless due to the thick tree canopies. Mortars and ammunition were heavy and bulky since they had to be hand-carried by Marines. But they were an important part of the rifle company's arsenal.