Reference Build · Technical Manual
Brushless AEG SSG Build Guide (V2 Gearbox)
End-to-end technical manual for converting a V2 AEG into a brushless single-sector DMR using the 6mmCustoms reference parts list.
- Level
- Advanced
- Bench time
- 12–16 bench hours
- Platform
- V2 gearbox AEG (M4/HK416/Krytac/KWA/VFC)
- Reference parts cost
- $331.93
Out of scope
GATE Titan/Aster electronics, Maxx cylinder heads, and Warhead-branded brushless motors are intentionally excluded from this guide. The shop does not service builds specified with those parts; substitute the components listed below.
Chapters
Choosing the Correct Parts
Why brushless SSG builds are pickier about parts than a brushed AEG, the components 6mmCustoms refuses to use, and the canonical drop-in list we build around.
Finding the Right Tools
The bench kit a brushless SSG build actually needs — adhesives, abrasives, lubricants, hand tools, and the test gear that catches problems before they leave the shop.
Bushing Installation
Bonding 8mm steel bushings into a Retro Arms shell so they never rotate, never walk, and stay perfectly concentric under brushless cycle pressure.
Piston Alignment
How to mount the piston head with AOE washers so the piston slides without bind through the spring-guide bore — the prerequisite to a quiet, low-wear cycle.
Air Compression Assembly
Greasing the cylinder, head, and nozzle correctly, cycling the assembly to bed the grease evenly, and the syringe leak test that catches every problem before the shell closes.
Motor Grip AOE
Verifying the motor-grip-to-lower-receiver alignment before shimming, and how to sand a stock or aftermarket grip flat so the pinion sits true to the bevel.
Sanding and Polishing Gear Axles
A noticeable reduction in gear noise from polishing the gear axles against the bushings. Skip for bearings; mandatory for any bushing build.
Bevel-to-Pinion Shimming
Reference shimming materials from the techs we trust, with a before/after photo of a 6mmCustoms brushless SSG build after the shim and gear-axle polish.
Tappet Plate Timing
Tappet fin geometry for a single-sector brushless build, the calipered cut spec, and the short-stroke pairing required for any selector that includes auto or burst.
MOSFET / ETU Installation & Tuning
Installation reference guides for each of the three MOSFET/ETU brands we approve, plus the brushless-specific gear-clearance check for GATE units.
Barrel Cutting, Crowning & Polishing
Cutting an inner barrel to length without burring the bore, crowning the muzzle so BBs exit on-axis, and polishing the bore for consistent flight.
Hop-Up Assembly
Installing the Airsoft Mutation LC 60° bucking and Infinity nub, setting initial hop, and matching the chrono ammo to the field ammo.
Final Testing & QA
Break-in sequence, QA checklist, and the symptom-to-cause table for the most common brushless SSG failures.
Reference parts list
Sourced from therealdealairsoft.com and brillarmory.com. This is the canonical catalog for the build; every chapter assumes these specific parts.
| Part | Price | |
|---|---|---|
| Real Deal Brushless 37k Adjustable Motor 2.0 (Splatter) Real Deal Airsoft Sensored brushless can with onboard ESC and adjustable timing/torque profile. 37k unloaded RPM lands inside the SSG sweet spot at 13:1 without cooking the spring. Direct drop-in to V2 short-type mounts. | Motor | $108.00 |
| SCYLLA V2 MOSFET (rear-wired) by Jefftron Jefftron Optical trigger, programmable semi/burst/auto, pre-cocking, active brake. Pairs cleanly upstream of the Real Deal ESC — Jefftron handles trigger logic, the motor's onboard ESC handles commutation. | Trigger control | $79.99 |
| Ultimate Performance Piston 2025 (SSG) Real Deal Airsoft Full-steel-rack SSG piston pre-cut for sector-clipped engagement. Survives the higher cycle rate brushless builds run without rack shear. | Piston | $42.99 |
| Real Deal High Speed Piston Head Real Deal Airsoft Bearing-equipped, lighter return mass, better seal repeatability at brushless cycle rates, and pairs natively with the Real Deal piston body so the pre-corrected AOE stays intact. | Piston head | $14.99 |
| Real Deal Optimized POM Nozzle (21.00mm) Real Deal Airsoft POM self-lubricates against the tappet rail and seals the bucking lip without an O-ring strangler. Length sized to standard M4 hop chamber. | Nozzle | $8.99 |
| TRDA Tappet Plate (V2) TheRealDealAirsoft Reinforced tappet rail handles the snap of a brushless cycle. The OE polymer plate cracks at the spring tab inside a season on a clipped-sector build. TRDA plates are stiffer and more consistent than Guarder or stock equivalents. | Tappet plate | $12.99 |
| Rocket / SHS M100–M170 Spring Rocket Linear-rate, lot-consistent springs. Pick the M-rating that lands 5–10 FPS under field chrono on a 0.20g BB through your finished compression chain. | Spring | $9.99 |
| F.L.T. 8mm CNC Steel Bushings FLT (via Brillarmory) 8mm steel bushings are the bare minimum for a brushless SSG. Bearings will pit at this cycle rate; solid steel runs cooler and stays concentric. | Bushings | $20.00 |
| Airsoft Mutation High Precision Shim Set (Engraved, 30pcs) Airsoft Mutation (via Brillarmory) Laser-engraved thickness on every shim removes the guess-and-feel step. Full range from 0.10mm to 0.50mm. | Shims | $7.00 |
| Real Deal Krytac Spur Spacer Real Deal Airsoft Required on Krytac V2 shells to land the spur at the correct height when running aftermarket steel gears. Skip if the donor is not a Krytac. | Spacer | $4.99 |
| Airsoft Mutation LC Bucking — AEG (60°) Airsoft Mutation (via Brillarmory) 60° flat-hop bucking. Slightly softer than the 65° variant for better grip on 0.32–0.40g BBs at DMR FPS. The reference bucking for this build. | Hop bucking | $13.00 |
| Airsoft Mutation Infinity Bucking Hop-Up Nub (3mm) Airsoft Mutation (via Brillarmory) 3mm concave nub matched to the LC bucking. Even pressure across the patch, no fishhooks. | Hop nub | $9.00 |
Shop favorites
Additional parts the 6mmCustoms shop currently endorses for this build. Pulled live from the parts catalog.
| Part | Price | |
|---|---|---|
| Airsoft Mutation High Precision Shim Set [Engraved, 30pcs] brillarmory.com | Misc. Small Parts | $7.00 |
| Airsoft Mutation High Precision Shim Set [Full Set, Engraved, 50pcs] brillarmory.com | Misc. Small Parts | $10.00 |
| Airsoft Mutation Infinity Bucking Hop-Up Nub (3mm) brillarmory.com | Hop-Up Parts | $9.00 |
| Airsoft Mutation LC Bucking - AEG (65 Degree) brillarmory.com | Hop-Up Parts | $13.00 |
| F.L.T. 8mm CNC Steel Bushings brillarmory.com | Bushings/Bearings | $20.00 |
| Maxx Model CNC Hop Chamber M4E (Standard M4) therealdealairsoft.com | Misc. Small Parts | $79.98 |
| Perun Lightning V2 Mosfet 2026 therealdealairsoft.com | Misc. Small Parts | $59.99 |
| PTS Enhanced Polymer Grip - Compact (EPG-C, FDE) - AEG brillarmory.com | Externals | $20.95 |
| PTS EPG-C M4 Grip therealdealairsoft.com | — | $19.99 |
| Real Deal 6.02mm Stainless Steel Inner Barrel therealdealairsoft.com | Misc. Small Parts | $29.99 |
| Real Deal Airsoft Grease therealdealairsoft.com | Misc. Small Parts | $9.99 |
| Real Deal Brushless 37k Adjustable Motor 2.0 Splatter (PRE ORDER) therealdealairsoft.com | Misc. Small Parts | $108.00 |
| Real Deal Cylinder Head therealdealairsoft.com | Misc. Small Parts | $10.99 |
| Real Deal Cylinders therealdealairsoft.com | Misc. Small Parts | $12.99 |
| Real Deal High Speed Piston Head therealdealairsoft.com | Misc. Small Parts | $16.99 |
| Real Deal High Speed Sector Delay Chip therealdealairsoft.com | Misc. Small Parts | $4.99 |
| Real Deal Hop Chamber Shims therealdealairsoft.com | Misc. Small Parts | $4.99 |
| Real Deal Optimized CNC Gearset therealdealairsoft.com | Misc. Small Parts | $38.00 |
| Real Deal Optimized POM Nozzles therealdealairsoft.com | Misc. Small Parts | $8.99 |
| Real Deal Performance Anti Reverse Latch therealdealairsoft.com | Misc. Small Parts | $6.99 |
| Real Deal Replacement Pinion Gear therealdealairsoft.com | Misc. Small Parts | $9.99 |
| Real Deal SHS Bevel Gear therealdealairsoft.com | Misc. Small Parts | $9.99 |
| Real Deal SUPER STRENGTH Tappet Spring Pack of 2 therealdealairsoft.com | Misc. Small Parts | $6.00 |
| Real Deal Ultimate Tappet Plate therealdealairsoft.com | Misc. Small Parts | $12.99 |
| Rocket/SHS M100-M170 Springs therealdealairsoft.com | Misc. Small Parts | $9.99 |
| SCYLLA V2 Mosfet by Jefftron therealdealairsoft.com | Misc. Small Parts | $79.99 |
| The Real Deal Airsoft 8mm Low Profile Bushings CNC therealdealairsoft.com | Misc. Small Parts | $14.00 |
Required tools
Loctite Blue (242)
Thread-locker for piston-head screw, motor mount, MOSFET hardware, hop screws. https://amzn.to/3NPi1jw
Loctite Retaining Compound or JB Weld
Bushing-to-shell bonding. https://amzn.to/47kO6qg
Ball-peen hammer
Pairs with the punch set to seat bushings flush.
Punch set
Brill Armory bushing/punch set works: https://www.brillarmory.com/index.php?main_page=product_info&cPath=51_60&products_id=1203
Phillips screwdrivers (all sizes)
V2 hardware spans #0 through #2.
Flathead screwdriver (standard)
Trigger-group prying, spring-guide bayonet, hop-arm tabs.
Gear grease — Insidious Armory
Gears and O-rings. https://www.therealdealairsoft.com/products/insidious-armory-gearbox-grease — code 6MMCUSTOM
Dedicated O-ring grease
Light silicone, do not cross-contaminate with gear grease. https://amzn.to/3RNYAc1
Teflon tape
Cylinder-head and nozzle wraps when sealing a non-Real Deal head. https://amzn.to/3RO4pWG
Torx bit set
Required for Retro Arms gearbox shell fasteners.
Paper towels
Excess glue and grease cleanup. Lint-free preferred for compression parts.
Isopropyl alcohol (90%+)
Degrease bushing seats, hop chamber, optical sensor windows. https://amzn.to/4aM5gzN
Brasso
Stock-barrel polishing only. https://amzn.to/3S5LrfK
Rotary tool (Dremel)
Sector clipping, AOE tooth re-shape, gear-axle polishing, barrel crowning.
Digital calipers (0.01mm)
Tappet plate cuts, shim stacks, nozzle length.
Compression syringe with V2 nozzle adapter
Mandatory leak test before closing the shell.
Chronograph
Real chrono with 0.5 FPS resolution — phone-mic apps are not acceptable.
Soldering iron (60W+), leaded solder, heat shrink
Re-terminating the harness for the MOSFET / ETU.
LiPo-safe charger
3S balance charging for the recommended battery.