The American-made M1 81mm mortar was a derivative of the MLE-27/31 system made in France. It became the standard mortar of American battalions during World War II and saw action in both the Korean War and the Vietnam War until the lighter M29 system was designed.

The M1 81mm mortar was made up of three main components: the firing tube, bipod, and the baseplate. When fully assembled, this mortar weighed 136 pounds. Muzzle velocity was noted at 700 feet per second thanks to the smoothbore firing tube. The sustained rate fire for this weapon was 18 rounds per minute; the operated loaded the M1 by dropping the prepared projectiles into the muzzle. The projectile’s primer and the ignition cartridge were activated via a firing pin at the base of the firing tube followed by the corresponding action launching the round at the desired angle. Since the operator(s) only needed to protect themselves after the projectile was dropped in the tube, a maximum rate of fire of 30 to 35 rounds per minute was achievable. The M1 could fire at a maximum range of 3,300 yards with an elevation of +40 to +85 and a traverse of 14 degrees.

M1 81mm mortars could utilize a wide variety of ammunition types, including:

• M43A1 Light High-Explosive

• M45 and M45B1 Heavy High-Explosive

• M56 Heavy High-Explosive

• M57 FS White Smoke Round

• M57 White Phosphorus

• M301 Illuminating Round

This mortar was transported via a two-man handcart that was simply designated as the “Hand Cart M6A1.” This allowed the M1 to be transported into defensive positions with relatively little issue and for the least about of crew to move the system about. The M3 Halftrack was another effective way to transport the M1, as it allowed for the crew and the weapon to stay on the vehicle. A specially devised harness could be placed on a mule as another option.