CQBR Block II

Development and Origins

The CQBR Block 2 emerged as part of the SOPMOD Block II program, which began addressing Block I shortcomings around 2005. Initial efforts centered on improving optics for dual CQB/long-range use, such as piggyback mini-red dots on ACOG sights (e.g., SU-237) and red dot magnifiers, as operators needed to engage threats from room-clearing distances to over 500 meters in dynamic environments like urban Iraq or mountainous Afghanistan. The program formalized in late 2007, with the Naval Surface Warfare Center Crane Division (NSWC-Crane) overseeing integration of commercial off-the-shelf components.

Key to Block 2 was the adoption of the Daniel Defense RIS II rail system, introduced in 2007 to replace the cramped Knight's Armament Company (KAC) Rail Interface System (RIS) from Block 1. This upgrade provided full-length Picatinny rails extending to the muzzle device, enabling better accessory mounting without compromising barrel harmonics. Development involved collaboration with Daniel Defense, Insight Technology, and L3 Communications, with phased rollouts: optics and lasers by late 2007, rails by 2007-2010, and lights/suppressors refined through 2015. The CQBR upper itself evolved to "Type 3" (Colt-contracted with accessories) and "CQBR2" markings around 2010, denoting Block II compatibility. Unlike Block 1's ad-hoc modifications from shortened M4A1 uppers, Block 2 standardized low-profile gas blocks and free-float designs for improved accuracy and reliability. Production continued alongside Block 1, with over 10,000 CQBR units total across variants.

This iteration built on Block 1's 1999-2000 foundations but was shaped by combat feedback from the early Iraq and Afghanistan wars, where limited rail space hindered night-vision and light attachments. By 2010, "CQBR2-X" serials marked NSW-specific uppers, transitioning to broader "10/14 series" (10 for 10.3-inch CQBR, 14 for 14.5-inch M4A1) across SOCOM.

Adoption and Operational Use

Adopted starting in late 2007 by U.S. Special Operations Command (SOCOM) units, the CQBR Block 2 quickly became the standard for elite forces requiring versatile CQB platforms. Navy SEALs (NSW) led initial fielding, using it for Visit, Board, Search, and Seizure (VBSS) and direct action raids, followed by Army Special Forces (USASOC), 75th Ranger Regiment (REG), Marine Special Operations Command (MARSOC), and Air Force Special Operations Command (AFSOC). By 2014-2015, full kits reached forward-deployed teams in Afghanistan, where the Mk 18 Mod 1 (Block 2 CQBR upper on M4A1 lower) excelled in mountain patrols and house-to-house fighting.

It supplemented or replaced Block 1 in high-threat scenarios, with configurations varying by unit: MARSOC favored tan SureFire lights and PEQ-16 lasers, while USASOC emphasized Aimpoint CompM4 optics post-EOTech controversies. The system saw extensive use in Operations Enduring Freedom and Iraqi Freedom, enabling suppressed, IR-laser-guided engagements up to 650 meters with Mk 262 ammo. By the mid-2010s, it expanded to non-SOF roles like NCIS protective details and Coast Guard tactical teams, though remained SOCOM-primary.

PARTS LIST

Lower Receiver

Lower Receiver: Colt A2 profile Lower w/ UID Label
Stocks: LMT Sopmod Gen 1/Gen 2 Black/FDE, Colt CAR, Magpul CTR (Various Others)
Grip: Standard A2, Ergo, Magpul Miad (Various Others)
Trigger: Colt, Geissele SSA/SSA-E
Trigger Guard: GI
Rear Sling Mount: CQD