Taken by Associated Press photographer Đặng Vạn Phước on February 26, 1968, a U.S. Marine patrols through the urban terrain that made up the city of Huế during the Battle of Huế which raged from January 31, 1968 to March 2, 1968. The battle was one of the biggest engagements of the Tết Offensive that had been launched by both the Quân đội Nhân dân Việt Nam (People's Army of Vietnam; PAVN) and the Việt Cộng on January 31, 1968. While the Battle of Huế ended in victory for U.S. and South Vietnamese forces and spelled decline of the Việt Cộng as a fighting force, the battle was the longest single combat of the war and also the costliest in terms of the lives of troops as well as civilians. In addition, the Battle of Huế and the Tết Offensive as a whole was one of the pivotal moments of the Vietnam conflict which majorly swayed public opinion against the war. In part, this was due to military officials having reported the Việt Cộng menace as being well under control. The reporting by public media on the Tết Offensive clearly showed that the Việt Cộng and their allies were still well able to attack in large numbers and inflict significant casualties which were displayed across television screens and print media.
Returning to the Marine, he likely belonged to either 1st. Battalion, 1st. Marine Regiment or 2nd. Battalion, 5th. Marine Regiment, both of which were heavily involved in the street combat within Huế. The photograph is of interest because of what can be seen underneath the barrel of his Colt M16A1 5.56mm assault rifle: the short lived Colt XM148 40mm grenade launcher.
Called the CGL-4 and designed by Karl R. Lewis for Colt (development having commenced in 1964), the intent was to replace the M79 40mm grenade launcher which was similar to a squat shotgun as it used a break-open breech for loading the grenade. But for the grenadier, it meant not only did he have to carry his M16 rifle (some grenadiers only carried a pistol sidearm instead of a heavier rifle), but he also had to carry the M79 which added to his burden in the field. The XM148 was designed to integrate the grenade launcher with the rifle and thus eliminate the need for the grenadier to carry two separate weapons. The CGL-4 was accepted by the U.S. Army following a competition and in July 1966, Colt received an order for a little over 20,000 XM148 grenade launchers with the first deliveries to be completed and received in South Vietnam for issue by December 1966. By the summer of 1967, the order had been delivered in full.
The XM148 was connected to the M16A1 by way of a special handguard that replaced the standard M16 handguard of the rifle. To load, the grenadier pushed the barrel forward by depressing a button on the back of the grip (seen here held by the Marine's left hand) and tilting the grip forward to release it from the catch. Once the single 40mm round was loaded, the grenadier then pulled the barrel back to the closed position using the grip until it locked on the catch. The launcher was cocked by pulling back on a lever (hidden in shadow in the photograph) on the rear of the breech. The trigger for the XM148 was interesting in that it extended past the magazine well. This allowed the grenadier to fire the launcher without taking his hand off the rifle's pistol grip. The trigger can be easily seen in the picture. Not visible is the launcher's sight which was fitted to the left side of the weapon. This was an adjustable, articulated sight with a front post that had a maximum graduation of 400 yards. Also on the left side of the XM148 was a safety lever. All told, the XM148 had a weight of 3.1 pounds (compared to 6.5 pounds of the M79) and was 1.4 feet long. With a muzzle velocity of 244 feet per second, the effective range of the XM148 was 400 yards.
Unfortunately for the U.S. military, the XM148 did not perform well in the South Vietnam theater of operations. The launcher was relatively complex and had numerous small components that had a bad habit of getting lost when soldiers serviced the weapon in the field. Another major problem was the extended trigger. As it was exposed, the launcher's trigger was subject to accidental discharges either by the soldier himself or the weapon getting caught on foliage or the soldier's own equipment. Despite the trigger having between a 6 to 11 pound trigger pull, in the heat of battle, this could easily be overcome. Another complaint by troops was the 30 pound trigger pull of the cocking lever as well as the sight that protruded from the left side was also prone to getting caught on equipment and branches.
By May of 1967, the XM148 was declared by the U.S. Army to be unsuitable for field use but some lingered on in front-line service (mainly with special forces) until it was replaced by the 40mm M203 under-barrel grenade launcher in 1969. Besides U.S. Marines using the XM148 in limited numbers, the U.S. Air Force Security Forces also utilized it as well as the Australian Special Air Service Regiment. Amazingly, the U.S. Air Force continued to use the XM148 for training purposes through the 1980s with the last XM148 launchers finally disappearing from military use in the early 1990s.
Primary Source:
Owen, J.I.H. Brassey's Infantry Weapons of the World (New York: Bonanza Books, 1979)
