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ALL REMAINING KITS IN THIS BATCH NOW INCLUDE A PROJNUT BARREL CLAMP. Please see additional installation instructions on this page.


Is your barrel nut too tight? NOTICE: hop unit threads tolerance issue on this batch, please read here. Projnuts are now included as part of the Genesis kits to solve this problem.

Hop wheels in this batch will have the option of 12 custom anodising colours and patterns. The hop units in this batch will all be GOLD, the nozzles in this batch will all be GOLD. Hop units and hop wheels will feature latest CNC engraving, not lasered white. 


This is an 12-piece kit that provides you with all the parts required to make your KJW KC-02 compatible with the wide variety of VSR/GBB hop rubbers and VSR barrels out there in the airsoft world (because the standard KC-02 barrel, rubber and hop unit are proprietary to the KC-02), but also does soooo much more! Over a year of development and testing went into this kit, as well as an extensive beta-testing programme with airsoft tech experts around the world.

You can watch the walk-through and installation video here:

The diagram in the pictures explains much of the detail of each part, here's a high-res download link for it:

The kit contains 12 parts:

  • KC-VSR Cylinder-Nozzle V6, 7075 CNC aluminium, GOLD anodised
  • Genesis Hop Unit V5, 6061 CNC aluminium, GOLD anodised
  • Diadem Hop Wheel V5, 7075 anodised CNC aluminium
  • Projnut Brass Inner Barrel Clamp
  • 3 x Hop Keys: Arch (gold), Bridge (blue), Flat (purple). 6061 CNC aluminium
  • 3 x Flow Restrictors: Low (green - under 350fps), Medium (blue - under 400fps), High (red - under 500fps). 6061 CNC aluminium. Maximum power is achieved by not using a flow restrictor at all. Actual power output will depend on barrel length, ammo weight, gas type and other upgrades.
  • 1 x 3mm neodymium magnet, for use with standard KJW hop wheel
  • 1 x 2.5mm steel cylinder cross-pin

This kit solves problems with poor air seal, solves the problem of broken cylinders, allows greater control of hop pressure and adjustment resolution, allows use of a huge range of existing VSR hop rubbers and barrels, and many other small improvements in functionality. It is a quantum leap forward in the performance and upgradeability of the KC-02 platform that has never been done successfully before.

Testing has shown that 50 degree hardness hop rubbers with short barrel (eg. 370mm) or 60deg with a long barrel (eg. 510mm) are best suited for this hop unit due to the amount of pressure it applies when using heavy ammo such as 0.36g - 0.48g weights.

The latest improvements to the Genesis kit should reduce the amount of bedding-in time required after installing the new parts, but some manual dry-racking may still be required for a few minutes. We recommend plenty of lubrication then cleaning inside the gun once it cycles smoothly.

The most common area to cause problems is the top of your trigger mech above the valve striker where the cylinder slides across the top of the trigger mech between the "turrets". This area usually has some rough casting in the corners which needs to wear down to suit the new cylinder. This isn't a problem for everybody but some of our beta testers used a file to smooth this area first. We found that racking the gun a couple dozen times and cleaning, followed by just shooting the gun for a while was more than sufficient to cut this area to the new parts.

As always, contact us via Facebook if you've got any questions.

Barrel and Hop Rubber Combo's we've tested and confirmed they fit, though performance varies:

  • 50deg Flamingo rubber + ML Crazy Jet barrel
  • 60deg Flamingo rubber + ML Crazy Jet barrel
  • 60deg Flamingo rubber + TNT barrel (bridge removed)
  • 60deg Airsoft Philosopher rubber and barrel
  • 60deg G&P VSR rubber + Prometheus VSR barrel
  • 60deg TM VSR rubber + R-hop Prometheus VSR barrel
  • 70deg ML Autobot rubber + ML Crazy Jet barrel
  • 60deg ML Autobot rubber + ML Crazy Jet Barrel
  • 60deg PDI rubber + R-hopped PDI barrel
  • Laylax purple rubber + Laylax 6.03 barrel
  • 60deg ML Monster rubber + Laylax barrel
  • 60deg ML Delta rubber + Laylax barrel
  • EDGI barrels in "TM Pistol" cut (unbridged)

PLEASE NOTE: Do not install the metal C-clip on the hop rubber that comes with Maple Leaf hop rubbers. It is not necessary and will cause cycling problems as the grip on the nozzle will be too tight.

Please note that the hop keys and flow chokes in this batch have not been anodised due to manufacturing difficulties and time constraints. They are instead painted with an acid etch primer and touch acrylic paint. So please avoid contact with strong solvents that may remove the paint.

NOT NOVRITSCH SSQ-22 Compatible!!

Design difference in position of the hop screw prevents the use of our Genesis and Master Precision hop systems with the Novritsch SSQ-22.

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