The Colt Monolithic CQB SBR 5.56 NATO is a compact short-barreled rifle built around a 10.3-inch barrel and a black finish (Colt part no. LE6945CQB). Colt names it for its monolithic upper, where the receiver and the rail system are a single piece rather than a separate handguard bolted on at the barrel nut. That one-piece layout gives a continuous top rail from the rear of the receiver forward, so an optic, a magnifier and a light can share a single straight line. It feeds from 30-round magazines and keeps the familiar Colt AR controls. For a short rifle aimed at vehicle carry, home defense or close-quarters training, it is a factory-built answer from the company that defined the platform.

Key Specifications

• Chambering is 5.56 NATO, the standard carbine cartridge with the deepest choice of training and defensive loads.
• Barrel length is 10.3 inches, the short length that gives this rifle its CQB proportions.
• The upper is a one-piece monolithic receiver and rail, which keeps the top rail continuous for optics and accessories.
• Magazine capacity is 30 rounds, the common AR pattern that keeps spare magazines easy to source.
• The finish is black, a low-glare color that suits a duty-style rifle.

Frequently Asked Questions

How long is the barrel? The barrel is 10.3 inches, which keeps the rifle short enough for vehicles, hallways and tight spaces.

Do I need ATF approval to buy this? No. As of October 9, 2026, ATF no longer requires Form 4 approval, registration or a tax stamp for short-barreled rifles. It transfers on a Form 4473 with a background check through a Class 3 (SOT) dealer. State and local laws still apply. Taking an SBR across state lines still requires an approved ATF Form 5320.20.

What does monolithic mean on this Colt? The upper receiver and the rail are machined as one piece, so the top rail runs unbroken from the receiver to the front of the handguard.

Buy the Colt Monolithic CQB SBR, 5.56 NATO, 10.3-Inch

As of October 9, 2026, this short-barreled rifle transfers on a Form 4473 with a background check at your Class 3 (SOT) dealer, with no Form 4 or tax stamp; state and local laws still apply. Order through Colt‘s short-barreled rifles lineup and our Lubbock, Texas team will handle the transfer. It is a compact Colt carbine with a rail that stays in one piece from end to end.