Ballistic Advantage Modern M4 Barrel

16-Inch M4 Carbine Barrel

The Ballistic Advantage Modern M4 Barrel is a 16-inch replacement or build barrel for the AR-15, chambered in 5.56 NATO and cut to the familiar M4 carbine profile. It suits shooters assembling a general-purpose carbine from parts and owners swapping out a worn or shot-out barrel. The barrel ships ready for a gas block, gas tube and muzzle device of your choice.

Features

• 5.56x45 NATO Chamber — The chamber is marked 5.56x45 NATO and also fires .223 Remington, so you can shoot either cartridge from the same rifle.
• 16-Inch Length — The 16-inch barrel gives a compact, handy carbine.
• 1:7 Twist Rate — The rifling makes one full turn every 7 inches, a fast twist that stabilizes the heavier, longer bullets common in 5.56 loads.
• 4150 CrMoV Steel — Machined from 4150 chrome moly vanadium steel, a tough barrel alloy that holds up well to heat and sustained firing.
• QPQ Nitride Finish — QPQ is a salt bath nitride treatment that hardens the steel surface and resists corrosion inside and out.
• M4 Profile — The stepped M4 contour, including the cut near the muzzle, matches the standard military carbine shape and fits most AR-15 handguards.
• Carbine-Length Gas System — The gas port sits at the carbine position and takes a 0.750-inch gas block with a carbine-length gas tube.
• 1/2x28 Threaded Muzzle — The muzzle is threaded 1/2x28, the standard AR-15 pitch for flash hiders, compensators and muzzle brakes.
• M4 Feed Ramp Extension — The barrel extension has M4 feed ramps, the angled cuts that guide each round into the chamber, also QPQ treated.

Steel, Finish And Fit

The barrel is roll-marked with caliber, twist rate and steel grade (5.56x45 NATO, 1/7, 4150 CrMoV), so its specification is visible after assembly. It installs on AR-15 upper receivers in the usual way, with the indexing pin on the extension lining it up in the receiver. For the smoothest feeding, pair it with an upper that has matching M4 feed ramp cuts. Gas block, gas tube, muzzle device and handguard are sold separately.