The M16 rifle accompanied the US military when they entered the thick jungles and joined the warfare operations of the Vietnam War. What followed was its more compact, Cold War-era brother called the CAR-15 rifle, which Pentagon provided to the US Army Green Berets and US Navy SEALs commandos that later became one of the top modern special forces weapons for good reasons.

M16, Piece of Garbage

Before there was CAR-15, there was the M16.

In 1964, the M16 was introduced to the US military. A year later, these rifles were deployed to be used by the troops fighting in the jungles of Vietnam. It was made of composite plastic with smaller caliber bullets, so it was light with less recoil. One selling point of the gun was that the soldiers could carry more ammunition for the same weight since they were smaller. Another was its rounds supersonic up to 500 yards and capable of penetrating steel plating. There was also a claim that its fully automatic mode could fire up to 800 rounds per minute.

CAR-15 Was Born

The Colt Automatic Rifle-15, or CAR-15, is an M16 rifle-based firearm sold by Colt Manufacturing Company in the 1960s. The company purchased the rights to the AR-15 rifle from ArmaLite before exclusively producing the rifles for the Department of Defense. 

CAR-15 was derived from the Colt Model 607 carbine, Colt’s solution to the short rifle problem. It featured a sliding buttstock that reduced its overall length. The barrel was shortened from 20 inches to 10 inches. Moreover, the new design had a forward assist mechanism in the upper receiver and push-button to advance fresh cartridges into the battery.

The CAR-15 is gas-operated and has a gas tube that leads from halfway down its barrel down to the piston on the top of the bolt. Its 20 and 30-round magazines fire the 5.56x45mm M193 round at a cyclic rate of 700 to 900 rpm, depending on whether the fore selector is semi-automatic or fully automatic. It also has an effective range of 300 m.

Commando’s Rifle

Many countries, including the United States, acquired the CAR-15 for officers and special units. In June 1966, the Pentagon signed a contract with Colt for 2,815 Colt “Commando” rifles, officially called the “Submachine Gun, 5.56-mm, CAR-15.” They delivered the first rifles within six months: the unmodified Colt 607s, the designated XM177 used in Air Force service, and the XM177E1 for the Army service.

The soldiers’ feedback was that the shortened barrel resulted in a giant fireball at the muzzle and a loud gunshot. They also had issues with accuracy and felt the buttstock was too complicated. As a result, Colt modified the initial rifles and returned with the improved Colt 629 Commando. It had a longer 11.5 inches barrel and a redesigned flash hider. The chamber was also chrome-plated to prevent gunpowder residue from accumulating in the upper receiver.

The US Navy SEALs is another special forces unit that used the CAR-15 in action. Before that, they carried the Colt 607 but later transitioned to the XM177E2 once available. The United States Army Special Forces and SEALs continued to use the E2 until the 1970s, even when they had to take parts from other files to provide spare parts for the others due to the lack of new production.

The Colt Commando was replaced by the M4 carbine in the 1990s when the US Army officially adopted it. The M4, although not as short as the CAR-15, is more reliable and refined in design. However, the M4 is not the standard weapon assigned to the US Army and Marine Corps. For the Navy SEALs, they were issued the Mk.18 Mod 0, with a ten ½-inch barrel.