The RetroArms CNC Split Gearbox V2 (8mm) – QSC 2025 is a CNC split gearbox for Version 2 airsoft replicas, intended for platforms such as AR15/M4, M16, MP5, and other V2/Tokyo Marui-compatible builds. RetroArms machines it from a single block of EN AW 7075 T651 in the Czech Republic, and the official page clearly labels it as an airsoft part, not for real gun.

The split design makes assembly and maintenance easier: the upper section can be removed without taking the entire gearbox out of the receiver, while the Quick Spring Change (QSC) system allows spring changes without fully opening the gearbox. The official description also highlights practical improvements such as more stable spring seats, an AOE inspection window, wider wire channels, a release hole for the anti-reversal latch, and centering grooves between the two shell halves.

Technically, this is the 8mm version, meaning the bushing/bearing holes are sized for 8 mm components, and it is designed for Tokyo Marui standard parts. The official page also states that screw torque should not exceed 1.2 Nm, and that if the spring guide is not secured properly, the gearbox may jam and suffer damage to the piston, gears, motor, and shell.

Technical features

• Model: CNC Split Gearbox V2 (8mm) – QSC 2025.
• Item No.: 7066.
• EAN: 8596308070668.
• Material: EN AW 7075 T651.
• Manufacturing: CNC machined.
• Compatibility: AR15/M4, M16, MP5 and other V2 airsoft replicas.
• Version: 8mm.
• System: Quick Spring Change (QSC).
• Weight: 142 g.
• Warranty: 24 months.
• Marked as airsoft part, not for real gun.

Package contents

• 1 CNC Split Gearbox V2 (8mm) – QSC 2025.
• Screw set and QSC spring guide.

How to use

• Install the gearbox only on compatible airsoft replicas, ideally with proper technical experience. The official page notes that installation can be difficult and requires skill.
• Use standard Tokyo Marui compatible components and never force parts into place.
• Tighten screws to a maximum of 1.2 Nm to avoid stripping threads.
• Secure the spring guide properly when using the QSC system to prevent spring twist, jamming, and mechanical damage.
• Use the split construction to simplify gearbox maintenance and internal adjustments.

Safety warnings

• Intended for airsoft only, not for real firearms.
• Do not tamper with, modify, or force the product.
• Do not exceed the manufacturer’s stated torque limit.
• Always ensure the spring guide is properly retained and the shell halves are correctly aligned.
• Keep out of reach of children.
• Use only in lawful contexts with compatible components.
• Improper installation can damage the mechanism.

The RetroArms CNC Split Gearbox V2 QSC 2025 is a very strong option for users looking for a premium, precision-made shell built for fast maintenance and demanding custom builds.