High-quality CNC-machined gearbox for CA/A&K-based M249 or PKM airsoft machine guns.
This gearbox is made from a single solid piece of aircraft-grade aluminum (Dural) EN AW 7075 T651, offering unmatched mechanical properties. Dural aircraft aluminum is extremely strong, capable of withstanding stress up to 590MPa (Ultimate Tensile Strength) before breaking. In comparison, standard tool steel withstands up to 390MPa. Thanks to the Dural material, Retro Arms CNC gearboxes are far superior in durability and quality compared to standard zinc-aluminum cast gearboxes.
Package includes:
- CNC Gearbox M249/PKM (8mm) QSC
- Screw set
Retro Arms improvements over the standard CNC M249/PKM gearbox:
- Internal spring slots are grooved to prevent the tappet plate spring from accidentally coming loose.
- Bearing seats are sized -0.02mm (7.98mm) smaller to prevent bearings from rotating in the seat. Edges of the bearing seats are rounded for easier installation.
- All sharp edges are rounded to maximize durability, as sharp corners create stress peaks under load.
- Gearbox halves fit precisely together thanks to CNC-milled alignment grooves.
- The gearbox has been redesigned in critical areas for increased strength.
Retro Arms gearboxes feature a Quick Spring Change (QSC) system, allowing the spring to be replaced through a rear plug using a hex key without fully disassembling the gearbox.
