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 ...

The CQBR, designated Mk 18 Mod 0, is a variant of the M4 family of carbines. Designed for Close Quarters Battle (CQB), the CQBR is significantly shorter than its M4 / M4A1 cousins, with a barrel-length of 10.3 inches compared to the M4's 14.5 inches.

The Special Operations Peculiar MODification (SOPMOD) kit is an accessory system for the M4A1 carbine, CQBR, FN SCAR Mk 16/17, HK416 and other weapons used by United States Special Operations Command (USSOCOM) special forces units, though it …

Feb 21, 2017 · The CQBR Upper Receiver is a drop in replacement for the M4A1 standard upper receiver and when installed is known as the Mk18 by type-designation. It was originally intended to replace the 9mm...

Apr 5, 2008 · The Colt CQBR (Close Quarter Battle Receiver) consisting of the Lewis Machine and Tool back-up sight and SOPMOD stock, Knight’s Armament RAS with rail protectors, vertical pistol grip and compensator (for use with KAC quick detach suppressor).

Aug 15, 2022 · The CQBR Upper Receiver is a drop in replacement for the M4A1 standard upper receiver and when installed is known as the Mk18 by type-designation. It was originally intended to replace the 9mm MP5 series of sub-machine guns with a weapon firing the common 5.56mm round capable of penetrating body armor, while still making use of SOPMOD accessories.

Mar 16, 2025 · The Mk 18 was originally known as the Close Quarters Battle Receiver (CQBR). It was developed by the US Naval Surface Warfare Center, Crane Division as a replacement upper receiver for M4 carbines issued to Navy SEALs.

A version with a 10' barrel / upper receiver, known as the CQBR, is also in use with Naval Special Warfare Units such as the SEALs, and opther SOF units. The M4A1 is a 5.56mmx45mm NATO caliber weapon with a gas operated, rotating bolt action. The carbine is typically fed from 30-round STANAG magazines.

The Close Quarter Battle Receiver (CQBR) is a replacement upper receiver for the M4A1 carbine developed by the US Navy. Quick Facts Type, Place of origin ... 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 CQBR, designated Mk 18 Mod 0, is a variant of the M4 family of carbines. Designed for Close Quarters Battle (CQB), the CQBR is significantly shorter than its M4 / M4A1 cousins, with a barrel-length of 10.3 inches compared to the M4's 14.5 inches.