Colt M4 Monolithic Carbine 5.56 NATO 16.1 in Matte Black

Description

The CR6940 is Colt’s monolithic-upper carbine — a platform built around a one-piece upper receiver and handguard that eliminates the barrel nut junction found on standard AR-15s. That construction removes a potential flex point and ensures the handguard, receiver, and barrel extension are indexed to a single aluminum forging, which matters when you mount a bipod or sling with any lateral load. It suits shooters who want a duty-grade carbine without rebuilding the factory configuration.

The upper’s monolithic design also means the handguard is a fixed, non-free-floating extension of the receiver rather than a separate rail section clamped over the barrel — a distinction that affects how consistent your support-hand position is across shooting positions. The gas system on this platform runs mid-length, which spreads the dwell time and pressure curve across a longer port-to-bolt distance than a carbine-length system. In practical terms that translates to a softer impulse with standard-pressure 5.56 and less heat transferred to the gas key over sustained strings.

The 1:7-inch twist rate is optimized for heavier projectiles — 62-grain M855 and heavier loads stabilize reliably, and the twist is fast enough to handle 77-grain open-tip match ammunition. Shooters running lighter 55-grain loads will still function fine, but the real accuracy advantage comes with bullets at the heavier end of the .223/5.56 range. The A2 front sight gives you a rugged, precise aiming reference that co-witnesses with the folding Magpul MBUS rear, letting you run an optic on the flat-top rail while retaining a credible iron-sight backup. The rifle ships with one 20-round magazine.

Shipping and availability: This item cannot be shipped directly to California, Rhode Island and Washington. It cannot be sold into Illinois and Oregon. Check your state and local requirements before ordering. This item must ship to a licensed FFL dealer for transfer.