Atlas Custom Works V2 Airsoft CNC BILLET Gearbox Shell for M4/M16 AEG Platforms, Black

A cracked V2 gearbox shell is a common failure point on M4/M16 builds. The plastic casting cracks around the cylinder window and behind the trigger group, especially under heavy spring loads or after a hard drop. This Atlas Custom Works billet shell replaces that weak point with reinforced metal construction.

The shell is CNC-machined from metal rather than cast polymer, with radius cuts at stress points to prevent crack propagation. It includes an anti-reversal latch window for smoother tuning. The package also includes a quick-change spring guide, which means you can swap springs without splitting the entire gearbox—a meaningful time saver when you're adjusting velocity for different field limits.

This uses the standard Version 2 gearbox footprint, the most widely supported shell in airsoft. Gears, pistons, springs, and cylinders are all off-the-shelf. However, fitment can vary by brand. Some rifles—particularly LT, G&G, and KWA models—may require modification to the receiver or shell for proper seating. Check your specific platform before ordering.

This is the shell only. Internals, motor, and electronics are not part of the package. You're either replacing a damaged shell or building a custom gearbox from the ground up.

Finished in black coating. Includes the shell and quick-change spring guide.