| 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 | 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[1] |
| Designed | 1999[2] |
| Produced | 2000–present[3] |
| No. built | 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)[4] |
| Effective firing range | 300 m (328 yd) |
| Feed system | 20- or 30-round detachable STANAG magazine |
| Sights | Iron sights and various SOPMOD sights |
The Close Quarter Battle Receiver (CQBR)[5] is a replacement upper receiver for the M4A1 carbine developed by the US Navy.
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 in (489 mm). With the stock collapsed, the overall length of the weapon is 26.75 in (679 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.
- ^ "MK18". Daniel Defense. Archived from the original on 14 April 2021.
- ^ "U.S. NAVY MK18 MOD O CUSTOM CLOSE QUARTER COMBAT WEAPON FOR THE SEAFARING SERVICE - Small Arms Review". 5 April 2008.
- ^ "SOCOM-MK18 Complete Rifle". danieldefense.com. 13 September 2023.
- ^ Johnson, Jeff (14 May 2003). "– CQB Receiver – M4A1 Carbine with 10-Inch Upper Receiver". NDIA. 2003 Joint Services Small Arms Section Annual Symposium, Exhibition, Firing Demonstration & Plant tour: NSWC. Archived from the original on 22 June 2022. Retrieved 22 June 2022.
{{cite web}}: CS1 maint: location (link) - ^ "NSWC CRANE SAVES $970K FOR NAVSEA SMALL ARMS OFFICE" (PDF). Defense Acquisition University. US Navy. 22 August 2008. pp. 85–86. Archived from the original (PDF) on 22 June 2022. Retrieved 22 June 2022.