The Bunker Buster
For the last few weeks, we have walked through the M72 LAW, the RPG-7, and the Carl Gustaf – three weapons that between them define the spectrum of man-portable anti-armor and assault systems that have shaped infantry combat since the 1960s. Each represented a coherent, and unique, design philosophy: the M72 disposable and simple; the RPG-7 cheap and reloadable; the Gustaf precise and multi-role. Today we look at the outlier – the weapon that does not fit neatly into any of those categories, was adopted by exactly one branch of the U.S. military, and spent its entire service life being replaced by systems that never quite replaced it: the Mk 153 Shoulder-Launched Multipurpose Assault Weapon, universally known as the SMAW.

The SMAW is a Marine Corps weapon, through and through. It was fielded in 1984 as a Marine Corps-unique system; the Army borrowed 150 launchers and 5,000 rockets for Desert Storm, then gave them back (as the FGM-148 Javelin was coming online in the mid-90’s, along with the increasing intent to adopt the Carl Gustaf to replace both the M67 Recoilless Rifle, and the positively awful M47 Dragon), and for four decades it has been the Corps’ primary tool for the mission the name describes: assaulting fortified positions. Not primarily killing tanks – though it can, to a point – but destroying bunkers, breaching walls, collapsing buildings, and suppressing crew-served weapons dug into hardened positions. That is a different set of mission requirements than any of the weapons we have previously covered in this series, and it produced a different weapon.
Where It Came From
The SMAW’s lineage runs through Israel, which is fitting – the Israelis have spent decades solving exactly the kind of close-quarters urban assault problems the SMAW was designed for. In the late 1970s, Israel Military Industries developed the B-300, an 83mm reloadable rocket launcher optimized for infantry assault operations. The Marine Corps, looking for a replacement capability after the collapse of the FGR-17 Viper program – the same procurement disaster that sent the Army to the AT4 – found the B-300 and adapted it for American service.

The American version added one distinctive and genuinely unusual feature: a spotting rifle. Mounted on the right side of the launch tube, this 9mm device fires ballistically matched tracer rounds at the target before the main rocket is launched. The idea was sound – use cheap tracer rounds to confirm the firing solution before committing an expensive rocket to the shot. In practice, it added weight, complexity, and required the operator to expose himself repeatedly to enemy observation while working through the spotting process. It was a British design concept grafted onto an Israeli launcher for American Marines, which gives you some sense of the SMAW’s somewhat eclectic ancestry.
The result weighed 16 pounds unloaded, fired 83mm rockets loaded from the rear, and entered service with the Marines in 1984 – the same year the Army was fielding the AT4 and the same period the M72 was being theoretically retired. In practice, all three ended up in service simultaneously, which tells you something about the difficulty of replacing any weapon system that actually works.
Combat Record
The SMAW’s combat record is built primarily around the Iraq War the began in 2003, and specifically around the Battle of Fallujah. In the street-by-street fighting of both the first and second offensives in 2004, the weapon found its calling. The SMAW-NE – “Novel Explosive,” which is the military’s characteristically understated designation for a thermobaric warhead – proved devastatingly effective against the fortified rooms, tunnels, and hardened positions that Iraqi insurgents had constructed throughout the city. A thermobaric warhead works by dispersing a fuel cloud and then igniting it, producing an overpressure wave capable of collapsing lightly constructed buildings and lethal to personnel in enclosed spaces. It is not a subtle tool.

When the SMAW-NE lacked the penetrating power to breach certain reinforced walls directly, Marines developed a two-shot technique: first fire a High-Explosive Dual-Mode round to punch a hole through the wall, then send the thermobaric round through the opening into the room behind it. Tactically effective, if somewhat baroque. The broader point is that the weapon was being adapted in real time to meet a combat environment no one had fully anticipated – which is, as we have noted throughout this series, what separates useful weapons from expensive museum pieces.
In Afghanistan and Iraq more broadly, the SMAW gave Marine infantry squads a direct-fire breaching and suppression capability that neither the M72 nor the AT4 provided. The Army, which had returned its borrowed SMAWs after Desert Storm, later developed its own derivative – the SMAW-D, designated the M141 Bunker Defeat Munition – a disposable single-shot version using the same warhead. Even the Army eventually admitted the mission was real.
The Spotting Rifle Problem & Mod 2
The original SMAW’s spotting rifle was its perpetual liability. It was over 30 years old by the 2000s, experiencing increasing failure rates, and the process of firing multiple tracer rounds to range a target was slow and exposed the operator. In 2013, Marines at Quantico tested a modified SMAW with thermal and laser range-finding technology that replaced the spotting rifle. The results validated the concept, and in 2015 the Marine Corps contracted for the SMAW Mod 2 – a complete overhaul that replaced the spotting rifle with a Modular Ballistic Sight, incorporating a laser rangefinder, ballistic computer, and thermal capability. Weight dropped from 16 pounds to 13 pounds. Fielding to the Fleet Marine Force began in November 2017.
The Mod 2 was, by all accounts, a significant improvement. It was also, almost immediately, announced as the weapon’s final iteration before replacement.
The Gustaf Takes Over
The Marine Corps has been transitioning to the Carl Gustaf M4 as its primary infantry shoulder-fired system – and in doing so, has eliminated the 0351 occupational specialty, the Infantry Assault Marines who were trained specifically in SMAW employment. The Gustaf’s broader ammunition family, lighter weight in its M4 configuration, and compatibility with laser-guided rounds made the case for consolidation straightforward. Why maintain two separate systems, two separate MOS pipelines, and two separate logistics chains when one weapon covers the mission set of both?
The answer, for forty years, was institutional inertia, procurement complexity, and the SMAW’s genuine effectiveness in the one role it was specifically designed for. Those are not trivial reasons. But the Gustaf’s evolution has finally rendered them insufficient.
The SMAW is not gone yet – it remains in inventory and, as of 2023, Ukrainian forces of the 68th Jager Brigade were documented using it in operations against Russian forces. Old weapons, as we have noted repeatedly [https://freedomist.com/are-you-sure-you-want-to-throw-that-away/] in this series, have a way of finding new wars to fight. But its role as the Marine Corps’ primary assault weapon is drawing to a close, replaced by the Swede that finally convinced everyone it could do the job better.
This forms a fitting end to this series on man-portable anti-tank weapons. From the M72 to the RPG-7 to the Gustaf to the SMAW – four weapons, four design philosophies, and one consistent lesson: the weapon that solves a real problem, solved well, outlasts every prediction of its obsolescence.
Next time, we’ll look into a weapon that didn’t work so well – the M47 Dragon.


























