CNC gearbox designed for M249 or PKM airsoft replicas. This gearbox is manufactured from one solid block of aircraft aluminium (Dural) EN AW 7075 T651, which has higher strength (590MPa) than common construction steel (390MPa). This material gives RetroArms gearboxes far better durability and resilience than common zinc-aluminium gearboxes.

• Spring holders have grooves, so the springs for tappet plate and trigger switch will not jump off
• Sockets for bushings/bearings have smaller diameter about -0,02mm (7,98mm), for non-overturning the bushings during installation. The socket edges are cut down for better installation
• Threads are shaped instead of cut for better strength
• Both of the gearbox halves are centred by milled grooves and edges
• Gearbox was re-designed to be lighter but stronger in the most critical parts
• Added groove for anti-reversal latch spring, so it will not jump off.
• Outer edges bevelled
• Protective anodizing to prevent corrosion

RetroArms gearboxes have a quick spring change system QSC, where you can remove the whole spring guide with a hex key and change the spring without having to open the gearbox. In this solution, you need to secure spring guide with a screw, commonly with AR 15 (M4) replicas, it is by stock screw. In situations where you have folding stocks or no stock at all, you have to secure the spring guide with a QSC screw.

CNC gearbox can be installed only in airsoft replicas with Tokyo Marui compatible standard. That means even the inner parts. Do not use excessive force during installation. Use only 1Nm torque on screws, otherwise the screws will overturn in heads. If you want to be sure that screws will sit perfectly, use thread lock.

IMPORTANT
Not compatible with MAXX cylinder heads