The Vietnam War was the first combat opportunity for "mechanized" infantry, a technically new type of infantry with its roots in the armored infantry of World War II, now using the M113 Armored Personnel Carrier. In addition, Armored Cavalry squadrons in Vietnam consisted largely of M113s, after replacing the intended M114 in a variety of roles, and Armor battalions contained M113s within their headquarters companies, such as the maintenance section, medical section, vehicle recovery section, mortar section, and the scout (reconnaissance) section. U.S. Army mechanized infantry units in Vietnam were fully equipped with the M113 APC/ACAV, which consisted of one headquarters company and three line companies, normally with an authorized strength of approximately 900 men. Ten U.S. mechanized infantry battalions and one mechanized brigade were deployed to Vietnam from 1965 until their departure in 1972.
Company D, 16th Armor, 173rd Airborne brigade was the first US Army armor unit deployed to Vietnam. It originally consisted of three platoons of M113s and a platoon of Self Propelled Anti-Tank Systems (SPATS). It was the only independent Armor company in the history of the US Army. Upon the company's arrival in Vietnam, a fourth line platoon was added; this was equipped with M106 4.2” mortar carriers (modified M113s). The mortar platoon often operated with Brigade infantry units to provide indirect fire support. It also deployed at times as a dismounted infantry unit. The remaining SPAT platoon was reequipped with M113s in late 1966 and the mortar platoon was deactivated in early 1967. From early 1967, D/16th had three line platoons equipped with M113s and eventually, its diesel version, the M113A1. It also standardized in late 1968 with three machine guns per track, one M2 .50 caliber and two M60 machine guns mounted on each side. After several years, the machine gun array varied considerably from APC to APC. The company conducted search and destroy missions, road and firebase security. Twenty-five D/16th paratroopers were killed in action and many more were wounded during the course of the war. D/16th ’s largest battle took place on 4 March 1968 at North Tuy Hoa. "During the day, the company lost 5 men killed, 16 wounded, and 3 missing (who are believed dead as two unrecogizable (sic) bodies were found). The enemy took a much greater loss. An estimated 2 enemy battalions, 85th Main Force (VC) and the 95th NVA Regiment, were rendered ineffective as they had 297 KIA's, with d-16 Armor receiving credit for killing 218." The revised official count for D/16 was 8 KIA and 21 WIA. The company commander, Captain Robert Helmick, was awarded the DSC, and many D/16th soldiers earned awards for valor. D/16 was awarded a Meritorious Unit Award for its actions in Vietnam. It was deactivated in 1969 and the company’s M113s were distributed to E Company, 17th Cavalry, 173rd Airborne Brigade.
M113s were instrumental in conducting Reconnaissance In Force (RIFs), Search and Destroy missions, and large invasions (incursions) such as during the U.S. invasion of Cambodia on 1 May 1970 and later Laos (Operation Lam Son 719) in 1971; all of which used the M113 as the primary work horse for moving the ground armies. While operating with Cavalry and Armor units, the M113s often worked in conjunction with U.S. M48 Patton and M551 Sheridan tanks. During the Vietnam War, U.S. Army gun trucks (modified 2½-ton and 5-ton cargo trucks), along with V-100 armored cars, conducted convoy escorts for military traffic.
The USAF used M113 and M113A1 ACAV vehicles in USAF Security Police Squadrons, which provided air base ground defense support in Vietnam. M113s were also supplied to the South Vietnamese Army of the Republic of Vietnam (ARVN). One notable ARVN unit equipped with the M113 APC, the 3d Armored Cavalry Squadron, earned the Presidential Unit Citation. M113s were also supplied to the Cambodian Khmer National Armed Forces, equipped with a turret for the machine gun and a recoilless rifle mounted on the roof.
The Australian Army also used the M113 in Vietnam. After initial experience showed that the crew commander was too vulnerable to fire, the Australians tried a number of different gun shields and turrets, eventually standardizing with the Cadillac-Cage T-50 turret fitted with two .30 cal Browning machine guns, or a single .30/single .50 combination. Other turrets were tried as were various gun shields, the main design of which was similar to the gun shield used on the U.S. M113 ACAV version.
In addition, the Australians operated an M113 variant fitted with a Saladin armored car turret, with a 76 mm gun as a fire support vehicle, or FSV, for infantry fire support. This has now also been removed from service.
Subsequent to Vietnam all Australian M113 troop carriers were fitted with the T50 turret. The FSV was eventually phased out and replaced with a modernized version known as the MRV (medium reconnaissance vehicle). The MRV featured a Scorpion turret with 76 mm gun, improved fire control, and passive night vision equipment.
In March 2007, a group of U.S. Army soldiers sit on the rear ramp of an M113, staging for a reconnaissance mission in Forward Operating Base Kalsu, Iraq.
Today’s M113 fleet includes a mix of M113A2 and A3 variants and other derivatives equipped with the most recent RISE (Reliability Improvements for Selected Equipment) package. The standard RISE package includes an upgraded propulsion system (turbocharged engine and new transmission), greatly improved driver controls (new power brakes and conventional steering controls), external fuel tanks, and 200-amp alternator with four batteries. Additional A3 improvements include the incorporation of spall liners and provision for mounting external armor.
The future M113A3 fleet will include a number of vehicles that will have high speed digital networks and data transfer systems. The M113A3 digitization program includes applying appliqué hardware, software, and installation kits and hosting them in the M113 FOV.
The US Army stopped buying M113s in 2007, with 6,000 vehicles remaining in the inventory.
The Israel Defense Forces still operates large numbers of the M113 in its combat missions, from its total fleet of 6000 of the vehicles. On numerous occasions since their introduction in the late 1960s, the IDF's M113s have proven vulnerable to modern anti-tank missiles, IEDs, and RPGs, resulting in the deaths of many Israeli soldiers riding inside the vehicles. The IDF has nonetheless been unable to replace the use of them in combat operations, due to budget constraints in equipping its large mechanized infantry regiments.
In 2004, two fully laden IDF M113s were destroyed by IEDs, resulting in the deaths of 11 soldiers, all those inside the vehicles on both occasions. The vulnerability of the M113 armored personnel carrier to improvised explosive devices and rocket-propelled grenades, led the IDF to later begin to develop the Namer APC.
Operation Protective Edge 2014
In 2014, during Operation Protective Edge, a Hamas RPG-29 destroyed a fully loaded M113 in Gaza, resulting in the deaths of the 7 Golani Brigade soldiers riding inside the vehicle as part of Israel's ground incursion. As a result, the IDF faced calls to build more Namer APCs over the next decade and to gradually reduce the number of M113s used in its future combat operations.