Authored By Dan Alex (Updated: 8/27/2014):
Beginning in the 1920's, the US Army looked at procuring a light-class mortar system to fulfill such a need. Several mortar designs were entertained but the 60mm creation by Edgar Brandt was selected and license-production of the French system within the United States was granted. US Army evaluations soon followed, encompassing much of the 1930s, with the first eventual production order for some 1,500 examples put into motion sometime in January of 1940. The official designation of the American version became "Mortar, 60mm M2".
The M2 was made up of three major components consisting of the firing tube, baseplate and bipod. The firing tube was of a smoothbore design and made of metal, weighing in at 12.8lbs. The tube sat atop the metal rectangular M5 baseplate of another 12.8lbs. A 16.4lb bipod fitted to the upper half of the tube allowed the weapon to sit at an angle. The weight of the M2 system was listed at 42lbs and the barrel measured in at 28.6 inches in length. The mortar system was fully positional along its firing axis via mechanisms fitted at the bipod hinge, allowing for great accuracy at distance. In fact, the M2 was able to outdistance many of the light mortars of her day, explaining the popularity of the weapon from then on. Her elevation limitations were reported at +40 to +85 degrees with a 7-degree traverse. The operator managed an M4 collimator sight for trajectory adjustments (the same sight as found on the M1 81m Mortar system). The base cap sat within the tube and contained the firing pin. As a muzzle-loading weapon, the operator need only drop the mortar projectile down the mouth of the tube and protect himself from the subsequent launch blast. This method of operation allowed the mortar crew to supply a steady rate of accurate firepower in support of infantry operations before them. A trained crew could effectively fire off 18 rounds in a minute and reach ranges from 100 yards out to 2,000 yards with each projectile maintaining a possible 17-to 35-foot blast radius. A maximum rate-of-fire by a trained crew could reach 30 to 35 rounds-per-minute while extreme circumstances state a rate per minute of 100 rounds!
The 60mm 2.94lb mortar projectiles themselves were stout in shape, tapered at both ends, and stabilized in flight via multiple static fins. Muzzle velocity was approximately 518 feet per second. Available ammunition types included the primary M49A2 High Explosive (HE) round, the M302 white phosphorous smoke round and the 3.5lb M83 illuminating projectile round (25 second burn time). The M302 appeared somewhat late in World War 2 and could be used for both screening friendly movements or engaging enemy personnel as a deadly incendiary round. Practice rounds were made available for target training.
In practice, the M2 proved highly reliable and accurate as an indirect fire support weapon. The mortar system could be fielded at a moment's notice and directed for high-angled fire in both an offensive and a defensive role. With this capability, the M2 proved priceless in engaging enemies dug into trenches, ravines or along slopes. World War 2 alone accounted for the production of some 60,000 M2 systems. Production was handled by the Firestone Tire and Rubber Company as well as the Read Machinery Company and Kennedy-Van Saun Corporation.
The M2 did maintain its own level of limitations during her use. Perhaps most detrimental was the overall weight of the system as well as the weight of her ammunition. Though portable, the combined weight of the M2's bipod, firing tube and baseplate ultimately added up and the battlefield lethality of the mortar team was only as durable as its ammunition supply. Additionally, any mortar system suffered when engaging an enemy hiding under the protection of thick forest or jungle canopies where projectiles might find it hard to penetrate. Other than these points however, mortar teams proved invaluable to the base rifle company during the war. 60mm mortars served US military personnel in both the European and Pacific theaters - in the latter, they proved most effective against the dug-in and sometime suicidal Japanese troops.
A typical Marine mortar section in World War 2 was part of the Weapons Platoon, Rifle Company with its section leader being a Sergeant in rank. Three mortar squads were a part of this section with these being commanded by a Corporal. A total of 16 Marines made up the mortar section. The Weapons Platoon was deleted in May of 1944, relocating the mortar section under the control of company headquarters while operating in combat under the orders of the rifle company commander. Twenty Marines now made up the new 60mm Mortar Section.
French forces in Algeria and Indochina as well as South Vietnamese forces in Vietnam also utilized the M2.
Edgar Brandt's 60mm, 81mm and 120mm mortar systems went on to become something of a standard for the rest of the military world after World War 2, his designs copied to the extreme. His expertise also helped in the development of HEAT-based rifle grenades and HEAT warheads in general. He was credited with the invention of the discarding-sabot artillery shell. While his original business began in 1902 as the "etablissements Brandt", this has since evolved today to become the TDA Armements SAS under the Thales Group corporate banner.
The 60mm mortar, owing to its portability, came to be known as the a commander's "hip pocket artillery".