Colt167529646
Colt M4 Le6921 Upper Group 14.5In Stripped$513.89
Availability: In Stock
Current Stock: Out of stock
If you're running an M4A1-style AR-15 carbine or building one from the ground up, a genuine Colt M4/M4A1 replacement barrel assembly gives you the same mil-spec foundation that Colt built for the U.S. military. This 14.5-inch barrel assembly is the complete package—barrel, extension, nut, and front-sight tower all together—so you can drop it onto your lower and get to the range without hunting down individual parts. Colt's expertise in direct-impingement rifle design is baked into every detail, from the chamber and rifling to the gas system tuning.
The barrel is chambered in 5.56 NATO and features six-groove rifling with a 1:7-inch twist rate, a time-tested combination that handles everything from 55-grain varmint loads to heavier 77-grain match rounds. The M4-style feed ramps ensure reliable chambering, and the chrome-lined bore resists corrosion—a critical feature if your rifle sees hard use or less-than-ideal storage conditions. The carbine-length gas system delivers the handling characteristics M4 shooters expect: a compact profile with reasonable recoil impulse.
The muzzle is threaded 1/2"-28 TPI, so you can mount suppressors, flash hiders, or muzzle brakes to suit your mission. Whether you're outfitting a new build, replacing a worn-out barrel, or upgrading a rifle you've inherited, this Colt assembly spares you the gunsmithing and headspace guessing—it's engineered to work.
| Barrel Length | 14.5 inches |
| Chambering | 5.56 NATO |
| Rifling | Six-groove |
| Twist Rate | 1:7 inch |
| Gas System | Carbine-length |
| Muzzle Threading | 1/2"-28 TPI |
| Feed Ramps | M4-style |
| Bore Lining | Chrome-lined |
| Included Components | Barrel, extension, barrel nut, front-sight tower, post, sling swivel |
Yes, if your AR-15 lower accepts a mil-spec carbine-length gas system and standard 1/2"-28 threaded muzzle. The Colt assembly is dimensioned to mil-spec, so it works with standard uppers and lowers. The included barrel nut, extension, and front-sight tower make installation straightforward for anyone comfortable with basic AR assembly.
The 1:7-inch twist rate and 5.56 NATO chamber handle a wide range of loads. It stabilizes heavier bullets like 77-grain match rounds as well as standard 55 to 62-grain service ammunition. Use commercially loaded 5.56 NATO or compatible reloads; do not use 7.62×39 or other non-NATO cartridges.
Yes. The bore is chrome-lined, which resists corrosion and extends barrel life under regular use and in humid or field storage conditions.
Yes. The muzzle is threaded 1/2"-28 TPI, the standard mil-spec threading for AR-15 barrels. You can install any commercial suppressor, flash hider, or muzzle brake with that threading.
SKU: 167528484 • Weight: 2.05oz
Availability: In Stock
Current Stock: Out of stock
If you're running an M4A1-style AR-15 carbine or building one from the ground up, a genuine Colt M4/M4A1 replacement barrel assembly gives you the same mil-spec foundation that Colt built for the U.S. military. This 14.5-inch barrel assembly is the complete package—barrel, extension, nut, and front-sight tower all together—so you can drop it onto your lower and get to the range without hunting down individual parts. Colt's expertise in direct-impingement rifle design is baked into every detail, from the chamber and rifling to the gas system tuning.
The barrel is chambered in 5.56 NATO and features six-groove rifling with a 1:7-inch twist rate, a time-tested combination that handles everything from 55-grain varmint loads to heavier 77-grain match rounds. The M4-style feed ramps ensure reliable chambering, and the chrome-lined bore resists corrosion—a critical feature if your rifle sees hard use or less-than-ideal storage conditions. The carbine-length gas system delivers the handling characteristics M4 shooters expect: a compact profile with reasonable recoil impulse.
The muzzle is threaded 1/2"-28 TPI, so you can mount suppressors, flash hiders, or muzzle brakes to suit your mission. Whether you're outfitting a new build, replacing a worn-out barrel, or upgrading a rifle you've inherited, this Colt assembly spares you the gunsmithing and headspace guessing—it's engineered to work.
| Barrel Length | 14.5 inches |
| Chambering | 5.56 NATO |
| Rifling | Six-groove |
| Twist Rate | 1:7 inch |
| Gas System | Carbine-length |
| Muzzle Threading | 1/2"-28 TPI |
| Feed Ramps | M4-style |
| Bore Lining | Chrome-lined |
| Included Components | Barrel, extension, barrel nut, front-sight tower, post, sling swivel |
Yes, if your AR-15 lower accepts a mil-spec carbine-length gas system and standard 1/2"-28 threaded muzzle. The Colt assembly is dimensioned to mil-spec, so it works with standard uppers and lowers. The included barrel nut, extension, and front-sight tower make installation straightforward for anyone comfortable with basic AR assembly.
The 1:7-inch twist rate and 5.56 NATO chamber handle a wide range of loads. It stabilizes heavier bullets like 77-grain match rounds as well as standard 55 to 62-grain service ammunition. Use commercially loaded 5.56 NATO or compatible reloads; do not use 7.62×39 or other non-NATO cartridges.
Yes. The bore is chrome-lined, which resists corrosion and extends barrel life under regular use and in humid or field storage conditions.
Yes. The muzzle is threaded 1/2"-28 TPI, the standard mil-spec threading for AR-15 barrels. You can install any commercial suppressor, flash hider, or muzzle brake with that threading.
SKU: 167528484 • Weight: 2.05oz