Colt M4 to M5 Commando Upper Reciever Kit

A compact rifle is only as rigid as the upper that holds the barrel.

This kit modernizes a legacy M4 with a complete 5.56 NATO upper: chrome-lined heavy barrel, one-piece free-floating M-LOK handguard, and a continuous MIL-STD-1913 top rail.

Performance Under Pressure: You move through tight space with carbine-length gas and a 1:7 twist, then fold or flip the Troy BattleSights as the shot presents.

Durability and Reliability: A self-centering barrel nut and keyed barrel extension keep the 11.5-inch heavy barrel from shifting when the rail is loaded.

Friction Removal: Direct impingement, a one-piece handguard, and an ambidextrous Radian Raptor charging handle cut the fuss between pickup and first round.

Identity Signal: Folding Troy metal sights on this black upper read as a finished conversion, not a patched carbine.

Proof and Credibility: Complete conversion kit with an 11.5-inch chrome-lined heavy barrel, improved barrel retention interface, Raptor charging handle, and Troy folding sights.

Put a modern upper on the lower you already run.