Development of the weapon started in the United States in February 1958. A very original concept for the time it was created, the LAW supposed to be a light rocket, that could be carried by the soldier, and the container it was carried in was at the same time the launcher for the rocket and could be discarded after firing. First tests of the new weapon occurred in the end of 1959 and the weapon was standardized in March 1961 for the US Army, and later for the Marines as the M72 LAW (Light Antitank Weapon). The LAW replaced the M20 launcher firing the 3,5 inch antitank rocket and also the antitank rifle grenades. The weapon consists of a 66 mm caliber rocket and two tubes sliding one inside the other, of which the outer constitutes dust- and waterproof container for the rocket and the firing mechanism. Before using the weapon the operator must drop the front and rear cover, slide the inner tube to the rear and disengage the safety. The launcher has a reticle front sight graduated in 25-meter range increments. The launcher’s rear sight has a mechanism that automatically adjusts it to the ambient temperature to compensate for temperature-dependent changes in rocket motor parameters etc. The lever-type trigger is located at the top of the weapon. After sliding the inner tube out to firing position the weapon is no longer waterproof, even after restoring it to carrying position. The exhaust gases of the rocket motor, which stops its work before the rocket exits the launcher, can be as hot as 760 degrees Celsius. The launcher is open to the rear, which allows for no recoil, but creates a dangerous back blast zone at the time of firing the weapon. This zone extends 40 meters to the rear of the launcher and 15 degrees from the longitudal axis of the weapon. After exiting the launcher the rocket deploys 6 stabilizing fins and has to travel at least 10 meters for the fuse to arm – if it hits something before the fuse will not work.
During the Vietnam War the early LAWs were frequently used by the Americans, mostly to destroy fortifications, but also as means of countering the expected threat from North-Vietnamese tanks. For the first time the threat materialized during the fights for the Lang Vei Special Forces camp. Unfortunately the LAWs proved insufficient and the camp was lost.
There were many variants of the M72 developed, including the training version, designated M190, which can be reloaded with the 35 mm-caliber M73 training rocket. Other version are:
| Launcher length (closed): | 630 mm |
| Launcher length (extended): | 881 mm |
| Rocket caliber: | 66 mm |
| Rocket length: | 508 mm |
| Service weight: | 2,3 kg, including rocket: 1 kg |
| Muzzle velocity: | 144,8 m/s |
| Armor penetration capacity: | 300 mm |
| Maximum range: | 1000 m |
| Effective range (moving/stationary target): | 165 m / 200 m |
