Atlas Custom Works AAP-01 Aluminum Outer Barrel Type B, Green

If you're running an Action Army AAP-01 and want to shave weight without going full steel, the Atlas Custom Works Type B outer barrel is the upgrade. It swaps the stock barrel for an aluminum one that keeps the same external profile and fit, so your existing handguard and muzzle devices still line up.

Why aluminum. Aluminum is lighter than steel and resists corrosion without needing extra treatment. At 60 grams, this barrel won't add noticeable heft to your carry, and it won't throw off the balance you're used to on the range. It's also durable enough for regular field use — not a showpiece, just a functional swap.

Fit and compatibility. This is cut specifically for the Action Army AAP-01 GBB platform. It threads and seats to the same tolerances as the factory barrel, so you don't need to hunt for adapters or special tools. If your pistol is stock or running common AAP-01 internals, this barrel should drop in without fuss.

What you get. Just the outer barrel. No installation hardware, no mock suppressor, no inner barrel. You'll need your own basic tools to swap it out, and if you're also upgrading the inner barrel or hop-up unit, plan on checking headspace and air seal afterward.

Green finish. The green colorway matches certain AAP-01 variants and aftermarket furniture sets. It's a cosmetic choice — the finish doesn't indicate a performance spec or compatibility restriction.