When the secret commandos of MACV-SOG began running covert operations "across the fence," that is, outside of the borders of South Vietnam and into the portions of the Ho Chi Minh Trail in Laos and Cambodia, they needed firepower. All they could scrape together, and then some. And for good reason.
If they were lucky, in the early days, they could sneak around for a few days before discovery. In the later stages of the war, they were almost always spotted at insertion, so heavy had security on the Blood Road become. In both cases, once they were blown, they ran for their lives. Dodging blocking units, circling back to ambush those tailing them, they fought extended battles with grit, guts, and their wits. Their lifeline was the radio they carried and the immense airpower they could bring to bear in an emergency to make their escape.
Made up mostly of seasoned, combat-experienced Green Berets and given carte blanche to carry whatever they wanted, the SOG men experimented. A lot. And what they came up with for those bare-knuckle fights in the jungles of Indochina had a tremendous impact on the US Army during and long after the Vietnam War.
The typical recon patrol for OP-35 Ground Operations (MACV-SOG's recon teams) was small. In Laos, it often was just 3 American SF soldiers and 5 "indigs" (indigenous CIA-hired mercenaries, usually Montagnard tribesmen or ethnic Chinese Nungs -- averaging just 5' 2.5" and 108 lbs.). These small 8-man patrols often took on hundreds, even thousands of North Vietnamese Army troops in one battle. SOG went by the cover name Studies and Observation Group as a deniable cover for its top-secret mission, but those "running recon" for SOG called it Suicide on the Ground, and only partly in jest. Over 300 American SOG men died on those harry recon missions, and 80 have never come home, declared MIA to this day. No recon man was ever declared captured by Hanoi.
What the SOG teams developed for breaking contact at the point of discovery was nasty -- a sawed of grenade launcher, toted as a pistol and carried in a makeshift holster or on a lanyard around the neck. According to Major John L. Plaster, a former SOG man and prolific historian of the unit, this was a perfect combination. Recon men could carry the handy and well-balanced CAR-15 carbine, and if they needed more firepower their off-hand was ready to snatch up the cut-down M-79 and blast away an enemy squad. According to SOG man Sgt. John Meyer, "every American on ST Idaho carried a sawed-off M-79 for additional firepower. We thought of it as our handheld artillery." If each American on a SOG patrol carried the CAR-15 carbine and an improvised 40mm hand cannon, in addition to two of the indigs who carried M-79s, that meant as many as five grenade launchers per team. At the time a conventional US Army squad was issued only two M-79s (and many did not deploy more than one because it meant the loss of a rifle's firepower. The SOG men, not surprisingly, had figured out how to have it both ways -- they maximized their rifles and had as much 40 mike mike pumping out rounds down range as a whole platoon of ground pounders.
The hand cannon had some shortcomings. One was a purportedly nasty recoil and the result was that the barrel latch often cut the shooter's hand. But as Plaster said, "desperate men ignore recoil." To counter this, however, SOG requested a custom hand grip for their signature grenade launcher from the US Army Limited Warfare Laboratory at Aberdeen Proving Ground, Maryland. The LWL created an aluminum hand grip for what they termed the Hand Held Grenade Launcher (HAGL), which was delivered to Vietnam in 1970. The new hog leg was safer for the shooter and delivered less punishing recoil.
The ammunition for the SOG M79 was typical of most infantry units in Southeast Asia: high explosive. According to Meyer, however, "flechettes or double-ought (00) buckshot [were carried] for close contact." According to Frank Greco, the flechette grenades were custom loaded by SOG men, who scrounged the flechettes from the warhead of 2.75 inch rockets. Ammunition was often carried in canteen covers, which held eight rounds. Some SOG men wore the M79 grenadier vest, which held 24 rounds. For ammunition stats and especially of those for unusual rounds, see GURPS High-Tech.
Now, in the great Army tradition of the left hand not knowing what the right hand is doing, by the time the HAGL arrived in numbers, the US Army had already developed and deployed another option. In 1965 Colt Mfg. had developed the CGL-4, later designated the XM148. It attached under the barrel of Colt M-16 or CAR-15 (Oddly, early attempts had this frankenweapon attached to an M-1 rifle and a M-1 carbine). The Army sent some XM148 units to Vietnam. Lessons were learned.
The XM148 lacked a proper trigger, having instead a trigger bar with no trigger guard at all. This meant. not surprisingly, that the bar could be easily tripped -- by an errant tree branch, the soldier's body in a dive for cover, etc. -- or trapped by vegetation, rocks, folds of clothing...you get the picture. This was frankly just a weird gun; one commentator in Infantry magazine remarked that it was a "nightmare for the operator." On top of that, it had no sighting mechanism. You were supposed to aim it by estimation, Kentucky windage, or maybe by using The Force or something. Who knows.
Anyway, to fix the problems with the XM148 the US Army created a new weapon program: Grenade Launcher Attachment Development (GLAD...yes, seriously!). Well, ahem, GLAD used an earlier product idea by AAI, Inc. and developed the far superior XM203. This launcher had a proper trigger (and yes, folks, a trigger guard and a safety) and added proper ladder and quadrant sights for accuracy at range.
So just when the HAGL grip kits arrived in Vietnam, the XM203 showed up and seemed to solve the problem of what to use for grenade launchers on the SOG teams. But, not all were happy with the upstart XM203. According to Major Plaster, some of the “old school” SOG men didn't like the XM203 at all.
You see, according to Plaster, the new underbarrel attachment was, well, underwhelming. "[It] was detrimental to both arms...[because it] imbalanced the CAR-15." The lithe CAR-15 was now an ungainly, ugly duckling, having lost its enviable reputation for pointability and controllability. In addition, the new grenade launcher was slower to reload, and "could not achieve the firing rate or consistent accuracy of an M-79 by a well-trained Montagnard." Evaluation reports by the Army when the XM203 was tested with conventional troops supported Plaster's comments: they felt the weapon was awkward, unbalanced, and slower to reload.
Decades later the lessons of the M79 have not been lost on elite American operators. Reportedly, NAVY SEALS carry a cut-down M79 which they call "the pirate gun." Of course, it's now updated with collimating or red dot sight.
Let's explore some of the issues around this grenade launcher from a Tactical Shooting perspective.
In GURPS terms, the lithe CAR-15 goes from Bulk -4 to Bulk -5 when adding an XM203, bringing it up to the bog standard M16. GURPS Tactical Shooting gives a -1 to the shootist with the worst Bulk in situations using the rules under Who Draws First? This means where the SOG man with an unencumbered CAR-15 had an edge on a man equipped an M16, AKM or AK47, now he is tied on this mark. Likewise, a sawed-off M-79 pistol is Bulk -3, meaning it beats most long arms in a standoff. It goes without saying, Fast-Draw (Grenade Launcher) ought to be a thing for those carrying the cut-down M79!
The weapon weight jumps up, too, of course. A loaded CAR-15 weighs a svelte 6 pounds, but add the XM203 loaded at 3.6 pounds, and the total weight jumps to 9.6 pounds. These handle like very different weapons just based on the extensive weight difference alone. A GM wishing to draw distinctions between the weapons along the lines of Plaster's observations might rule any of the following game mechanics:
1. Treat the new CAR-15/XM203 weapon combo as a new familiarity requirement, meaning the shooter must spend time on the range until he has acclimated to both the new weapons, that is, for Guns (Rifle) and Guns (Grenade Launcher).
2. Perks and Techniques must also require familiarization, or else be learned all over again for this "new weapon."
3. Fast-Draw (Ammo, Grenade Launcher) is at a penalty for the XM203. The latching mechanism and the awkward balance of the weapon are markedly different than the most guns, whereas the M-79 handles like an overgrown shotgun. Additionally, GMs may consider giving the M-79 a situational bonus to Fast-Draw (Ammo), up to +2 in most awkward positions, again reflecting its simplicity and ease of use.
4. Another option is to make the XM203 Shots 1/4i, and keep the M-79 at Shots 1/3i. or make them 3i/2i respectively. This depicts the faster rate of fire some operators acquired with the M79.
5. The cut-down M79 was often kept on a lanyard, meaning that if the weapon was dropped the operator easily recover it, unlike with a conventional M79 or the XM203.
6. The M79 was often carried in a PRC-25 radio bag, protecting it from the elements. Unlike an XM203 which had to brave the elements of the Indochina environment all the time, the M79 was tucked away in its protective sheath and might deserve a bonus to HT rolls due to proper care. Granted, the XM203 did not develop a reputation as an unreliable weapon. Additionally, a hog leg might not be immediately recognized as a weapon if the enemy gets the drop on a recon man; he might be able to draw it and shoot his captors if his long arm is out of action.
Now all this said, the XM203 performed solidly in the field and was generally considered an improvement. In 1969, the US Army surveyed the grenadiers who had their M-79 replaced with the XM203. After weeks in operation with it the report concluded "83% of the respondents preferred to be armed with the XM203 in lieu of the M79." The same survey report said, "personnel armed with the XM203 consistently placed twice as much grenade fire on a target, when compared with those armed with the 79. This increased rate of fire was attributed to the mechanical extraction and ejection of the expended 4Omm cartridge case when the XM203 barrel was moved forward. With the M79 the firer had to manually eject the cartridge. In addition, the firer could move the XM203 barrel forward quicker than "breaking" the barrel of the M79."
One other thing to be pointed out is survey respondents claimed the XM203 reduced the tendency of the Ml6 to "climb" off-target when the latter was on automatic fire. This indicates it might act as a muzzle weight (GURPS Tactical Shooting, p. 76) to the host weapon's fire only.
What would a Tactical Shooting style using the grenade launcher look like in GURPS terms? Hmmm.
SOG Grenadier, 4 points.
Skills: Fast-Draw (Ammo), Fast-Draw (Grenade Launcher), Guns (Grenade Launcher).
Techniques: Close-Quarters Battle (Grenade Launcher); Dual-Weapon Attack (Grenade Launcher/Rifle); Immediate Action (Grenade Launcher); Retain Weapon (Grenade Launcher).
Perks: Grip Mastery (Grenade Launcher); Off-Hand Weapon Training
(Grenade Launcher); Quick Reload (Grenade Launcher); Unusual Training (Dual-Weapon Attack, Grenade Launcher/Rifle only); Weapon Bond.