The Shoulder-launched Multipurpose Assault Weapon has an 83.5mm diameter tube and fires 83-millimetre (3.3 in) rockets. It is a man-portable weapon system consisting of the MK153 launcher, the MK 3 encased HEDP rocket, the MK 6 encased HEAA rocket, and the MK217 spotting rifle cartridge. The launcher consists of a fiberglass launch tube, a 9mm spotting rifle, an electro-mechanical firing mechanism, open battle sights and a mount for the MK42 Day Sight and AN/PVS-17B night sights.
The SMAW MK153 Mod 0 launcher is an improved and enhanced development of the Israel Military Industries' B-300 weapon. The weapon consists of the launch tube, the spotting rifle, the firing mechanism and mounting brackets. The launch tube is made of fiberglass-epoxy composite material with a gelcoat on the bore. The spotting rifle is mounted on the right side of the launch tube. The firing mechanism mechanically fires the spotting rifle and uses a magneto to fire the rocket. The mounting brackets connect the components and provide the means for boresighting the weapon, while the encased rockets are loaded at the rear of the launcher. The spotting cartridges are stored in a magazine in the cap of the encased rocket.
The 9 mm spotting round is ballistically matched to the rocket and serves to increase the gunner's first-round hit probability. Each round consists of a special 9×19mm tracer bullet, crimped into a 7.62×51mm NATO casing with a .22 Hornet blank cartridge for propellant.The system can be used in conjunction with the AN/PEQ-4 aiming light in place of the spotting rifle.
Training is accomplished with the MK7 Mod 0 encased common practice rocket and the MK213 Mod 0 noise cartridge. At 152.3 decibels, the weapon is one of the loudest on the battlefield, second only to a mine-clearing line charge.
As with all of these types of rocket weapons, the backblast that is created when it is fires is a primary safety concern. The backblast extends in a 90-meter, 60° cone to the rear of the weapon. The backblast is lethal out to 30 metres (98 ft), and still extremely dangerous to 90 metres (300 ft). The resultant shock wave can even cause sympathetic detonation of unsecured ammunition. Rounds are under development that would enable a user to fire the rocket from an enclosed building without risk of injury.
A newer MK153 Mod 2 variant is currently in development. It features a modular ballistic sight (MBS) in place of the 9 mm spotting system. The MBS has a laser range finder and thermal weapon sight to provide a firing solution using a displaced reticle, where crosshairs are adjusted for distance and environmental factors. The MBS is lighter, more reliable, and can be detached from the launcher. While the Mod 0 weighs 7.5 kg (16.5 lb), the Mod 2 weighs 5.9 kg (13 lb) with the MBS attached, and 3.9 kg (8.5 lb) with the MBS detached. Other improvements include increased pad size on the forward grip and foldable backup sights. Mod 2 improvements are to be ready for fielding by early 2017.
The High Explosive, Dual Purpose (HEDP) rocket is effective against bunkers, masonry and concrete walls and light armor. Initiated by a crush switch in its nose, the HEDP rocket is able to distinguish between hard and soft targets resulting in greater penetration into soft targets for increased damage potential. The HEDP round is capable of penetrating 20 centimetres (7.9 in) of concrete, 30 centimetres (12 in) of brick or up to 210 centimetres (6.9 ft) of wood-reinforced sandbags.
The High Explosive Anti-Armor (HEAA) rocket is effective against current tanks without additional armor and utilizes a standoff rod on the detonator, allowing the explosive force to be focused on a small point and for maximum damage against armored targets. The HEAA round is capable of penetrating up to the equivalent of 600 mm of rolled homogeneous steel (RHA).
The Novel Explosive (SMAW-NE) rocket is effective against caves and bunkers. The SMAW-NE uses a thermobaric warhead, which produces an overpressure wave capable of collapsing a lightly constructed building. The Indian Head Naval Surface Warfare Center teamed with the Marine Corps Systems Command and Talley Defense Systems to responded to an urgent U.S. Marine Corps need for a shoulder-launched enhanced-blast warhead in 2003. It was used in combat during both the First and Second offensives in Fallujah 2004.