Colt M4 5.56 Upper Receiver Groups - M4 LE6921 Upper Group 14.5in With BCG And Sights
All Colt upper receivers
Click to see full view
Colt
Overview
The Colt M4 5.56 Upper Receiver Group features a complete assembly designed for the AR-15 platform, with a 14.5-inch barrel optimized for 5.56 NATO ammunition. This upper receiver is built with an M4 receiver type, ensuring compatibility with various lower receivers and enhancing overall functionality. It's commonly utilized in carbine gas system builds, making it a reliable choice for those looking to create a versatile and effective AR-15 configuration.
Specifications
Colt M4 5.56 Upper Receiver Groups - M4 LE6921 Upper Group 14.5in With BCG And Sights
Available Merchants
Price Alert
No Available merchants at this time.
Build history on GunPartPicker
Builders on GunPartPicker first added the Colt M4 5.56 Upper Receiver Groups - M4 LE6921 Upper Group 14.5in With BCG And Sights to a build in February 2026.
Updated · from real builds on GunPartPicker
Not sure which upper receiver to pick?
We ranked every upper receiver by how often it shows up in real builds on GunPartPicker.
Read the guide: Most Popular AR-15 Upper Receivers →Check it against the live catalog:
Frequently Built With
The part most often added in each category by the builds that include this one
Colt M4 Commando 5.56mm Semi-Auto Lower Receiver Assembly With "LE" Prefix
PSA Custom Fathers of Freedom 5.56 Full Auto Profile Phosphate Coated Bolt Carrier by Microbest
Radian Raptor Slim Line Ambidextrous AR-15 Charging Handle - Black
Troy Industries Carbine/M4 Enhanced Drop-In Battlerail - 7" Black
No reviews yet. Be the first to review this product!