The Colt LE6945CK Upper Receiver Conversion Kit (brand part no. LE6945CK) is a complete, one-piece monolithic upper assembly chambered in 5.56 NATO with a compact 10.3-inch barrel, built to Colt’s law-enforcement model-line specification and sold openly to any FFL-eligible buyer. Colt machines this upper as a single unitized receiver group rather than a separate upper and rail system, giving it exceptional rigidity for mounted optics, and finishes it in matte black to match standard AR-15 lowers. The 1:7 twist stabilizes the full range of 5.56 NATO bullet weights. Because it’s sold as an upper only, with no lower receiver included, it’s a standard AR-15 part — not a complete firearm — and carries no additional NFA considerations on its own. Among our AR15 uppers, this Colt conversion kit suits builders who want a genuine Colt monolithic upper without buying a complete rifle.

Key Specifications

• The chambering is 5.56 NATO.
• The barrel is 10.3 inches long.
• The rate of twist is 1:7 inches.
• The upper is a monolithic, one-piece receiver design.
• The upper ships as a complete assembly.
• The finish is matte black.

Frequently Asked Questions

Is this restricted to law enforcement buyers? No. “LE” is Colt’s naming convention for this model line; it’s sold openly to any FFL-eligible civilian buyer with no agency verification required.

Does buying this upper alone require NFA paperwork? No, a bare upper receiver with no attached lower is a firearm part, not a complete firearm, so it carries no NFA requirement on its own.

What makes it “monolithic”? The upper receiver and rail are machined as a single unitized piece rather than assembled from separate parts, giving a more rigid optics-mounting platform.

Buy the Colt LE6945CK Upper Receiver Conversion Kit

A genuine Colt monolithic upper built to a proven law-enforcement spec, the LE6945CK gives builders a rigid, compact 5.56 platform without a full rifle purchase. Order it from our Lubbock, Texas gun shop for fast shipping.