Atlas Custom Works 6061 Aluminum 125mm Hex Outer Barrel for TM Hi-Capa M11 CW GBBP, Silver

The Atlas Custom Works 5.1 inch hex outer barrel is a direct fit for Tokyo Marui-spec HiCapa GBB pistols. It replaces the factory barrel to add a more substantial profile, a machined hexagonal exterior, and a finished look that matches custom pistol builds.

What an outer barrel does. This is a cosmetic and protective upgrade, not a performance mod. It does not change velocity, range, or accuracy. The inner barrel and hop-up remain untouched, and the actual shot path is unaffected. The value here is the external appearance, the added rigidity around the front end, and the option to attach muzzle devices that fit the HiCapa platform.

Material and fit. Machined from 6061 aluminum, the barrel is lightweight but stiff enough to resist bending or marring during normal use. At 125mm (5.1 inches), it extends just past the frame of a standard HiCapa, giving a more balanced silhouette without turning the pistol into a carbine. The hex profile is a visual choice; some suppressors and adapters may require a slightly larger inner diameter to clear the flats.

Installation basics. You're swapping the outer barrel only, not the inner barrel or hop-up assembly. The kit includes two O-rings for the barrel seat, which help maintain proper alignment inside the slide. If your pistol has been previously upgraded, verify that the inner barrel and hop-up unit match TM-spec dimensions before installing. A few HiCapa variants use non-standard internals, and those may require additional fitting.

What this is not for. This barrel does not increase FPS, improve grouping, or change the gun's recoil characteristics. It is also not a drop-in for AK, M4, or other long-gun platforms — it is designed specifically for HiCapa GBB pistols with Tokyo Marui-spec internals.

Includes the outer barrel and two O-rings. Battery, gas, and BBs are not applicable to this item.