By Lance Brown
In a recent USMC Iraq incident after action report, there was a table listing all of the Class V (ordnance) items carried on the Cougar vehicle used during the incident. The one unfamiliar item was a listing for an M72A5.
First fired in October 1959, the Lightweight Anti-Tank Weapon (LAW) was a U.S. Army project based on a design by the Hesse-Eastern Division of Flightex Fabrics, Inc. Type classified in March 1961 as the M72 High-Explosive Anti-Tank (HEAT) rocket, the original LAW had a 2.6 inch (66 mm) diameter shaped charge warhead that was designed to penetrate 11.8 inches (300 mm) of mild steel and light field fortifications at ranges from 11-219 yards (10-200 meters). Propelled by a solid fuel propellant, the rocket utilized six folding fins for stabilization and reached a velocity of 500 feet (152 meters) per second. The disposable launcher was comprised of two interconnected tubes, with the forward (outer) tube being constructed of a fiber glass composite and the rear (inner) tube being constructed of aluminum. Immediately prior to firing, the operator was required to remove the covers from the forward end of the front (outer) tube and the rear of the rear (inner) tube and pull the rear (inner) tube to the rear, fully extending the launcher to approximately 35 inches (900 mm). Extending the rear (inner) tube simultaneously cocked the launcher’s firing pin, released the safety interlocks, and caused the integral sights to move via springs into firing position. Due to the open tube design, recoil was minimal to non-existent; however, back blast from the rocket firing could damage equipment or personnel up to 39 yards (36 meters) away from the launcher’s rear tube. Weight of the launcher with the rocket was 5.1 pounds (2.3 kg).
The M72A1 and M72A2 LAWs offered improved sights and a more powerful rocket motor over the M72, while the M72A3 provided safety upgrades to the rocket’s fuzing system. The more powerful rocket motor increased the effective and operational ranges to approximately 186 yards (170 meters) and 273 yards (250 meters), respectively, and increased the back blast danger area to 43.7 yards (40 meters). Weight of the system (rocket and launcher) increased to 5.5 pounds (2.5 kg).
In the mid 1980s, Talley Defense Systems began work on the improved LAW system, specifically the M72A4, M72A5, and M72A6 models. All share an improved rocket motor that increases rocket velocity to 650 feet (198 meters) per second and increases the effective and operational ranges to 241 yards (220 meters) and 383 yards (350 meters), respectively. However, back blast danger area increased to 76.5 yards (70 meters). Weight of the new systems is 7.9 pounds (3.6 kg), and the extended launcher length is 38.6 inches (980 mm). The primary difference in the newer models is the type of warhead utilized.
The M72A4 incorporates an improved shaped charge warhead explosively-filled with Octol that when coupled with the improved rocket motor, increases penetration capability against rolled homogeneous armor (RHA) to 14 inches (355 mm).
The M72A5 is the same shaped charge warhead utilized in the M72A3 model (differing only by utilizing Octol as the explosive fill) coupled to the new rocket motor. While the RHA penetration is the same as that achieved with the M72A3, the newer rocket motor increases the effective and operational range of the weapon.
A copper shaped charge warhead works well against solid steel targets. Against layered steel targets with air gaps or against masonry, it is far less efficient. For these types of targets, the M72A6 was developed. Utilizing an explosively formed penetrator (EFP) warhead that is explosively-filled with Octol, the M72A6 can penetrate 5.9 inches (150 mm) of RHA or can blast a man-sized hole in bricks, concrete, and masonry in urban environments when expedient breeching is required. The M72A7 contains the same EFP warhead, only the insensitive high explosive PBXN-9 is utilized as the explosive filler.
Models currently under development include a model that will allow firing from an enclosure (no damage to operator from back blast), an increased (to 17.7 inches or 450 mm) RHA penetration capability, and an anti-personnel model.
|This article first appeared in Small Arms Review V12N4 (January 2009)|