The Colt M4 Monolithic Carbine 5.56 NATO is a semi-automatic AR-pattern rifle built around a patented one-piece monolithic upper receiver with a continuous Mil-Spec rail (Colt part no. CR6940). A 16.1-inch free-floating barrel and 1:7 twist support accuracy, and a Magpul MBUS rear sight and folding front sight come on the rifle. A removable lower rail lets you add accessories where you need them. The reversible safety selector and M4 collapsible stock keep it familiar. This Colt carbine suits range work, home defense and optic-equipped general use.

Key Specifications

• The chambering is 5.56 NATO, a widely available cartridge for training and defense.
• Capacity is 30+1, the standard AR-15 magazine count.
• The barrel is 16.1 inches long, a carbine length that is easy to handle.
• The barrel is free-floating, which Colt says supports long-range accuracy.
• The rifling twist is 1-in-7 inches, a rate that stabilizes a range of 5.56 bullet weights.
• The action is gas-operated semi-automatic, the familiar AR design.
• The upper receiver is one-piece monolithic with a continuous Mil-Spec rail from the rear of the receiver to the front sight.
• Sights are a Magpul MBUS rear and a folding front sight, which stay out of the way when you add an optic.
• The rifle has a removable lower rail, which makes it easy to mount accessories under the barrel.
• The controls include a reversible safety selector, which suits right- and left-handed shooters.

Frequently Asked Questions

What is a monolithic upper? It is a one-piece upper receiver with a continuous Mil-Spec rail running from the rear of the receiver to the front sight, which gives repeatable optic mounting.

What sights does it have? It uses a Magpul MBUS rear sight and a folding front sight, so the rifle has backup irons.

What is the magazine capacity? Colt lists the capacity at 30+1 rounds.

Buy the Colt M4 Monolithic Carbine, 5.56 NATO, 16.1-Inch Barrel, Black, 30-Round

This carbine pairs a monolithic upper with proven M4 handling, which is a smart setup for an optic-equipped rifle. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL, and browse more AR rifles while you are here.