From Flamethrower to Rocket Box: The XM202 Story

Most of you will remember Arnold Schwarzenegger firing the M202 quad rocket launcher in the 1985 film Commando. In the popular imagination, a “flamethrower” usually means a heavy fuel tank strapped to someone’s back, a hose, and a very nervous operator spraying liquid fire a short distance across some patch of jungle. By the late 1960s, that classic setup was already dated, dangerous to its user, cumbersome, and too short-ranged for the bunker, trench, and tree line problems that American units kept running into in Vietnam.

The search for something better began in earnest in October 1966, when the U.S. Marine Corps issued a requirement for a weapon capable of firing an encapsulated flame round out to at least 100 meters. The idea was to replace the old backpack flamethrowers with a standoff weapon, something lighter, more portable, and safer to operate in a firefight. The requirement sharpened further in August 1968 when the U.S. Army’s 9th Infantry Division put forward its own request for a flame weapon that could neutralize bunkers from 200 meters or more. This became R&D program ENSURE 263.

A joint Army/Marine Corps team demonstrated the weapon in Vietnam between February and March 1969. The feedback was overwhelmingly interesting, and units saw the potential in having a “flamethrower”, which you could fire from hundreds of meters away without hauling a volatile fuel tank on your back.

The XM202 and its ammunition, the XM74 incendiary rocket, entered combat trials in Vietnam between 1969 and 1970. For these trials, 1,095 XM202 launchers and 16,740 XM74 rocket clips were delivered to U.S. forces for full-scale testing. The XM74’s warhead carried about 1.3 pounds of thickened pyrophoric triethylaluminium (TPA), a chemical that ignites instantly on contact with air. Thickening agents like polyisobutylene gave it staying power, helping it stick and burn in confined spaces, which is ideal for clearing bunkers or dense foliage.

Rockets were loaded in four-round clips, allowing for rapid reloading. The weapon had a maximum range of 730 meters and an effective range of about 260 meters, with an arming distance of 5–13 meters.

Initial evaluation involved the U.S. 4th, 23rd, and 25th Infantry Divisions and the 1st Cavalry Division. After a 90-day trial, the test pool expanded to include the 1st Infantry Division, 101st Airborne Division, 173rd Airborne Brigade, 11th Armored Cavalry Regiment, 199th Light Infantry Brigade, 1st Brigade of the 5th Infantry Division, and 3rd Brigade of the 9th Infantry Division.

The XM191 was the whole system, launcher plus ammunition. The launcher itself was the XM202, a shoulder-fired, four-barreled design. Each barrel fired a 66mm XM74 rocket, which reused the M72 LAW motor with a different warhead.

The hot part of the weapon was the TPA incendiary payload. Unlike napalm, TPA ignites the moment it meets air, burning white-hot. This made it particularly effective in jungle warfare, where the enemy could be dug in behind multiple layers of foliage and fortification.

The Army Concept Team in Vietnam (ACTIV) conducted the evaluations, and an interim report in March 1970 captured the entire story. From the Marine Corps requirement in 1966, to the Army’s reinforced need in 1968, to the in-country demonstration in early 1969, the XM191 system had been on a fast track. Units received training, ammunition, and detailed instructions, and the system was put to the test in real combat situations.

The ACTIV report’s goal was simple: determine if the XM191 worked in Vietnam’s operational environment, see how units actually used it, assess soldier acceptance, and identify any training or technical issues. In theory, it offered exactly what troops wanted: enough range to hit a bunker or tree line from safety, and enough incendiary effect to keep the target burning after the initial strike.

Feedback confirmed the weapon’s usefulness, but also flagged some drawbacks. Troops liked the range and power compared to backpack flamethrowers, and the ability to fire four rockets quickly was a significant advantage. However, the system was still considered somewhat bulky, and the specialized ammunition was another logistical burden, keeping enough clips forward in the field wasn’t always easy.

Final Thoughts

The system never became a frontline staple, but it filled a niche, quickly denying the enemy a position with fire from a safe distance. It was particularly suited for counter-ambush roles, clearing enemy cover, and creating instant area denial in dense terrain. The M202 served with both the U.S. Army and Marine Corps into the 1980s before being retired due to maintenance and safety issues. Pyrophoric agents like TPA required careful handling, and with the shift in military focus toward other weapons systems, the M202 series faded from service.

Still, the XM191/XM202 story is a classic Vietnam-era example of improvisation, taking a proven rocket motor, adding a new incendiary warhead, putting four of them in a shoulder-fired package, and handing it to troops who needed to root entrenched enemies out of concealed positions.

It didn’t change the course of the war, but it delivered exactly what the troops had requested in its narrow tactical role, lighting up a problem spot from beyond grenade range. While most people today know it as an action-movie prop, in Vietnam, it was a serious attempt to replace the old flamethrower with something far safer, longer-ranged, and devastatingly effective at the job.

Lastly, it’s worth touching on the Vietnam War’s possible role in influencing Soviet design. With the constant transfer of technology and intelligence during the conflict, it’s plausible that systems like the XM191 system found their way, directly or indirectly, into Soviet hands. Such exposure may well have sparked their interest in developing a counterpart. By 1975, the Soviets had adopted the MO-25 'Lynx,' marking the start of their enduring fascination with shoulder-fired thermobaric rocket launchers.

Sources: XM191 Multishot Portable Flame Weapon - ENSURE 263