Colt M4 to M5 PDW Upper Reciever Kit

Close quarters punish an upper that flexes when you hang real gear.

This kit converts a legacy M4 lower with a complete 5.56 NATO upper: 10.3-inch chrome-lined heavy barrel, free-floating M-LOK handguard, and a continuous MIL-STD-1913 top rail.

Performance Under Pressure: Carbine-length direct impingement and a 1:7 twist keep the short rifle honest when you clear a hall and need the first round to land.

Durability and Reliability: A self-centering barrel nut and keyed barrel extension lock the heavy barrel so the group does not walk as the handguard takes lights and pressure.

Friction Removal: The one-piece free-floating M-LOK handguard and continuous top rail let you hang optic, light, and sling without fighting clutter.

Identity Signal: An ambidextrous Radian Raptor charging handle and folding Troy metal sights mark a modernized M4, not a leftover carbine.

Proof and Credibility: This is a complete upper receiver conversion kit with a chrome-lined heavy barrel, improved barrel retention, and included sights and charging handle.

Convert the lower you already run and shoot a shorter, stiffer upper.