CNC Gearbox by RetroArms

CNC Gearbox V2 QSC is designed for AR15, M16, MP5, and other airsoft guns using the V2 gearbox. This model is made from aerospace-grade aluminum EN AW 7075 T651, which offers higher strength than standard construction steel, significantly outperforming traditional zinc alloy gearboxes. The main advantage is the Quick Spring Change (QSC) system, which allows spring replacement with just a hex key turn without fully disassembling the gearbox. During installation, the spring guide must be properly secured to prevent misalignment and component damage (ideally combined with the RetroArms QSC screw, sold separately).
CNC machining ensures precise dimensions and maximum compatibility with Tokyo Marui standard internal parts. Installation requires expert knowledge due to differences between airsoft replica manufacturers. The CNC gearbox is not just for increasing power with the strongest springs but primarily for improving durability and reliability, even with standard springs or in DSG/TSG high-speed setups.

Improvements in the 2025 Version

1. More precise motor gear alignment
   Slightly adjusted motor and spur gear positioning for improved motor engagement.
   
   
2. Extended nozzle movement
   The tappet plate allows for 0.3 mm more forward movement, ensuring better BB feeding and compatibility with shorter nozzles.
   
   
3. Improved cylinder seating
   The seating is redesigned to have 8 contact points instead of a full-contact surface, simplifying installation and compatibility with different manufacturers.
   
   
4. Optimized bearing fit (ANTIROT system)
   Added glue pockets or ANTIROT bearings to improve bearing stability during installation.
   
   
5. Increased front-end radius
   Provides greater durability and reduces the risk of cracking under strong spring loads.
   
   
6. Redesigned piston guide rails
   Improved geometry extends the lifespan of both the piston and gearbox, increasing overall reliability.
   
   
7. Enhanced fire selector rail
   Reworked selector plate rail allows for broader compatibility across various brands.
   
   
8. Inspection holes for piston positioning
   Added access points to quickly check piston placement during AOE adjustments.
   
   
9. Optimized wiring channels
   Extended rail for secure and stable cable routing, fully separating wires from the ambidextrous selector switch pin.
   
   
10. Redesigned space around piston and spur gears
    Improves compatibility with a wider range of gear manufacturers.
    
    
11. Added locking point for COMPRING anti-reverse latch
    New securing slot enhances anti-reverse latch stability and performance.
    
    
12. Better compatibility with a wider range of gears
    Reworked geometry allows for the use of more gear types without modification.
    
    
13. Refined surface finish
    Overall improved precision and surface quality for smoother installation and increased longevity.

Key Features

• Made from EN AW 7075 T651
  Extremely strong and durable material for long lifespan.
  
  
• Quick Spring Change (QSC)
  Easily adjust power output without dismantling the gearbox.
  
  
• Precision CNC machining
  Ensures perfect fit and compatibility.
  
  
• Reinforced front section
  Withstands high loads without deformation.
  
  
• Optimized wiring layout
  Better organization for easier installation without wire contact with gears.

Technical Specifications

• Model: AEG Gearbox V2 (TM Standard)
• Type: Full
• Bearing hole diameter: 8 mm
• Material: CNC-machined aluminum EN AW 7075 T651
• Version: 2025+

Package Contents

• CNC Gearbox V2 QSC
• Screw set
• QSC Spring Guide

Warnings

• Do not use cylinder heads with rubber bumpers (MAXX, FPS). This can permanently damage cylinder head mounting points, which is not covered under warranty. The rubber bumper can be removed, and washers can be used instead.
  
  
• The gearbox is optimized for JeffTron Leviathan and Scylla MOSFET units. Units from other manufacturers (e.g., PERUN) may require minor adjustments for proper fitting.
  
  
• When tightening screws, use a maximum torque of 1.2 Nm (medium-strength thread locker recommended).
  
  
• The gearbox has slightly smaller bearing holes (by 0.02 mm) to prevent bearing rotation after installation. Chamfered edges simplify installation. While designed for RetroArms ANTIROT bearings, standard round bearings can be used but should be glued (ensure adhesive does not contact the bearing surface).
  
  
• Proper alignment of the gearbox within the receiver is crucial to ensure a straight axis between the chamber, nozzle, and gearbox. This requires advanced technical skills. Installing a CNC gearbox correctly involves expertise in gear shimming, motor gear engagement, AOE tuning, tappet plate movement, cylinder head positioning, securing the spring guide, proper MOSFET installation, and fine-tuning the entire assembly within the replica body. Selecting the correct nozzle length, hop-up bucking, and chamber fitment is also essential. This is not a plug-and-play upgrade and should not be attempted by inexperienced technicians.
  
  
• Some manufacturers may require the use of the original spring guide or a modified guide for proper installation.