With the standardization of the RIFLE, 5.56 MILLIMETER, M16A2 (NSN 1005-01-128-9936), on 30 March 1982, Colt Defense LLC (CAGE 13629) set about to produce a carbine version of the M16A2 as they did for the M16A1 rifle. In early 1985, Colt unveiled the "M16A2 Carbine," which essentially was an improved version of the CARBINE, 5.56 MILLIMETER, M16A1 (NSN 1005-01-029-3866; also known as the model RO653 carbine). The weapon was marketed to both military and law enforcement as "...smaller, more compact versions of the M16A2 Rifle, intended for use wherever lightness and speed of action is required."
The M16A2 carbine's "lightweight" 14.5-inch barrel was upgraded from the M16A1 carbine's 1:12 twist rate to a 1:7 twist rate. This was done to improve performance of the barrel with the NATO STANAG 4172 62 grain SS109 5.56 x 45mm cartridge. The SS109 cartridge would later be standardized, on 10 June 1983, by the United States government as the CARTRIDGE, 5.56 MILLIMETER, M855 (NSN 1305-01-155-5458).
In addition to the new barrel, the following re-designed/improved parts were added to the M16A2 carbine:
(1) a new COMPENSATOR (NSN 1005-01-134-3633), Colt Defense LLC part 64502
(2) a new PLUNGER ASSEMBLY (NSN 1005-01-144-1468), Colt Defense LLC part 64541
(3) a new GRIP, RIFLE (NSN 1005-01-148-4805), Colt Defense LLC part 64576
(4) a new BUTTSTOCK ASSEMBLY (NSN 1005-01-371-1805), Colt Defense LLC part 64679
Colt assigned the model number RO723 to the carbine. By late 1985, the carbine was being equipped with the RECEIVER, CARTRIDGE (NSN 1005-01-248-5858; Colt Defense LLC part 64948) with cartridge case deflector (as found on the M16A2 rifle), but retaining the M16A1 "field sight." The RO723 received the nickname "Abu Dhabi carbine," as in 1987, the "sheikdom" of Abu Dhabi (part of the United Arab Emirates or UAE) ordered 20,000 units of the RO723.
With the adoption of the M16A2 rifle by the United States Army, in 1986, special operations units began looking into replacing their inventory of RO653 carbines with RO723 carbines. The RO723 carbines were purchased Commercial Off The Shelf (COTS) and not marked "PROPERTY OF U.S. GOVT." (as the M16A2 rifles were). Further, the RO723 was not considered a Limited Procurement Type item (like the RO653 was), so a National Stock Number was not assigned to the carbine.
[ABOVE] The RO723 as illustrated in the 1985 dated OPERATOR'S MANUAL FOR M16A2 CARBINE, COMMANDO & 9mm SMG (Colt Defense LLC part 94892).
[ABOVE] The RO723 as illustrated in the 1985 dated OPERATOR'S MANUAL FOR M16A2 CARBINE, COMMANDO & 9mm SMG (Colt Defense LLC part 94892) illustrating the round forward assist plunger, new upper receiver with cartridge case deflector and M16A1 "field sight."
The RO723 carbine was utilized by special operation forces (mainly with the United States Army) during many American military operations during the late 1980s through the 1990s. The RO723 was seen in use during Operations Just Cause, Desert Shield/Storm, and Restore Hope. Like the RO653, the RO723 was also called a CAR-15 by the grunts.
[ABOVE] Image dated 11 April 1991 and originally captioned "Security personnel, one armed with a 5.56mm M-4 Colt carbine, escort Gen. Norman Schwarzkopf, commander-in-chief, U.S. Central Command, as he walks toward Kuwait military headquarters after arriving by UH-60 Blackhawk helicopter to visit Kuwaiti dignitaries in the aftermath of Operation Desert Storm. Schwarzkopf will also be presenting awards to military officials who contributed to coalition efforts during the war." The "security personnel" are actually General Schwarzkopf's Personal Security Detail (PSD) and are all Delta operators. Of course, the weapon has been mis-identified. The weapon (carried by the operator at the right) is actually a RO723 carbine fitted with the new profile "notched" (for the M203's barrel mount) BARREL AND FRONT SIGHT ASSEMBLY (NSN 1005-01-233-8529). The barrel, even though standardized on 4 June 1986, has erroneously become known as the "M4 profile barrel." The carbine is further fitted with a CLIP, CARTRIDGE (the USGI designation for the Johnson Firearms REDI-MAG, NSN 1305-01-493-2955) and is slung using a standard SLING, SMALL ARMS (NSN 1005-00-167-4336) and KIT, ADAPTER, TOP SLING (NSN 1005-00-406-1570). The operator is SGM (retired) Michael Vining.