Close Quarters Battle Receiver
The Close Quarter Battle Receiver (CQBR) is a replacement upper receiver for the M4A1 Carbine, developed by the US Navy.
| Close Quarter Battle Receiver | |
|---|---|
Top: An M4A1 with SOPMOD Block 1 package, including Rail Interface System and Trijicon 4× ACOG. The barrel length is 14.5 inches (368 mm). Bottom: An M4A1 with a Close Quarter Battle Receiver. The barrel length is 10.3 inches (262 mm). | |
| Type | M4/AR15 Carbine |
| Place of origin | United States |
| Service history | |
| In service | 2000–present |
| Used by | See M4 Carbine users |
| Wars | War in Afghanistan Iraq War |
| Production history | |
| Designer | Colt Defense, Daniel Defense. |
| Designed | 1999 |
| Produced | 2000–present |
| No. built | Approx. >10,000 |
| Specifications (CQBR) | |
| Mass | 2.72 kg (6.00 lb) |
| Length | 762 mm (30.0 in) stock extended 679.4 mm (26.75 in) stock collapsed |
| Barrel length | 262 mm (10.3 in) |
| Cartridge | 5.56×45mm NATO |
| Action | Gas-operated, rotating bolt |
| Rate of fire | 700–950 round/min cyclic |
| Muzzle velocity | 2,585 ft/s (788 m/s) |
| Effective firing range | 300 m (328 yd) |
| Feed system | 20- or 30-round detachable STANAG magazine |
| Sights | Iron sights and various SOPMOD sights |
The CQBR features a 10.3 in (262 mm) length barrel (similar to the Colt Commando short-barreled M16 variants of the past) which makes the weapon significantly more compact, thus making it easier to use in, and around, vehicles and in tight, confined spaces. The overall length of the upper receiver is 19.25 inches (489 mm). With the stock collapsed, the overall length of the weapon is 26.75 inches (679.4 mm). Those created as complete rifles (rather than only upper receivers) are type designated as Mk 18 MOD 0/1.
Special forces units utilize the CQBR for scenarios such as VIP protection, urban warfare, and other close quarters battle (CQB) situations.
Its former preliminary National Stock Number (NSN) had been 1005-LL-L99-5996. A complete CQBR-equipped carbine now has the NSN 1005-01-527-2288.