AT3 Tactical .22LR Tapered Profile 4.5 Inch AR-15 Barrel Black. 22LR to your AR build with this tapered 4.5? barrel from AT3. Crafted from premium 4150 CrMoV steel per MIL-B-11595E specs and protected by a rugged black nitride finish. The tapered profile trims weight while maintaining accuracy with .22LR ammunition. At just 4.5? long with 1/228 muzzle threads its an ultra-compact option for dedicated .22LR AR uppers or PDW-style pistol builds. Designed for reliable cycling when paired with the AT3 .22LR bolt carrier group and Black Dog Machine magazines. This tough little barrel delivers consistent rimfire performance in a space-saving platform. Specifications for AT3 Tactical .22LR Tapered Profile AR-15 Barrel: Manufacturer: AT3 Tactical Color: Black Caliber: .22 Long Rifle Barrel Profile: Tapered Gun Make: AR Platform Gun Model: AR-15 Package Contents: AT3 Tactical .22LR Tapered Profile AR-15 Barrel What firearm models does the manufacturer say AT3 Tactical .22LR Tapered Profile AR-15 Barrel is compatible with? The manufacturer says that AT3 Tactical .22LR Tapered Profile AR-15 Barrel is compatible with AR-15AT3 Tactical AT3-22LR-4.5: .22LR Tapered Profile 4.5 Inch AR-15 Barrel Black