Shortly before midnight on July 12, 1970, Alpha Company of the 2nd Battalion, 501st Airborne Infantry Regiment, detected movement about 200 meters below its landing zone on a hill. Company commander Chuck Hawkins ordered his forward observer to engage the enemy with mortar fire. Caught bunched together, the North Vietnamese Army column was broken up. Some NVA troops withdrew, but others pressed on. As the NVA attacked the landing zone, Alpha Company crews in Fire Support Base Ripcord, equipped with M29A1 81mm mortars, fired several hundred rounds, about a third of them flares for illumination that enabled the forward observers to call in artillery fire that devastated the attackers that night.
The M29, which entered production in 1952, was almost 40 pounds lighter than its M1 predecessor and offered about 1,400 meters more in range. The improved M29A1 entered production in 1964 and had replaced the M29 in Army and Marine units by 1968.
Each fin-stabilized round weighed about 15 pounds and had a primer, ignition cartridge and four to nine propellant increments. The rounds came with a variety of fuzes. The high-explosive and white phosphorus illumination rounds had both point-detonating fuzes and proximity fuzes. The proximity fuzes—often called by their code letters VT fuzes—could be set to detonate about 1 to 6 meters above the ground, but heavy tree cover and vegetation often rendered such fuzing useless. Illumination rounds used timed fuzes. The gunner set the timing by using the M25 fuze setter. A well-trained crew could bring the rounds down to within meters of friendly troops or its own position.
The M29A1 could be broken into three major loads: the tube, the baseplate and a mount with elevating and traversing mechanisms. Because M29 mortars were heavy, infantry units increasingly left them at base camps and firebases. There, the mortar’s firepower broke up enemy assaults, disrupted ambushes and provided cover for forces engaged in close combat.
The M29A1 remained in service into the 1980s, when it was replaced by the lighter, longer-ranged M252 mortar of the same caliber.
Originally published in the April 2015 issue of Vietnam. To subscribe, click here.
