Retro Arms CNC Aluminum Hop-up Unit for V3 AK AEG



  • CNC machined aluminum 
  • Threaded collet nut to eliminate barrel torsion and vibration

Hop-Up chamber for AK airsoft replicas. This new Hop-Up chamber is manufactured from aircraft dural EN AW 7075, what have steel-like strengh and weight of aluminum so it is best material for use. Chamber is milled on CNC milling machine and it also has protective anodizing of 5µm silver color (0,005mm).

We build this Hop-Up chamber on results from testings, so this chamber is precise and custom-made constructed for best feeding and performance. We changed drill depth, so with 20,1 mm nozzle and Hop-Up 60 Shore bucking, we were able to get stable performance above 16m/s above spring power. Even feeding with heavy weight 0,43 BBs on SEMI and AUTO was without any problem.

retroarms-klestinova-matice-cnc-airsoft-new-genFor best setting of inner barrel, we created new innovation on our Hop-Up chamber – the collet nut connection. It is placed in front of Hop-Up chamber. You will just install inner barrel with Hop-Up bucking into the chamber, seal it with clip lock and in the end, screw it together to Hop-Up chamber  with collet nut (you will need 10 mm key). The collet nut is manufactured from aircraft dural EN AW 7075 and after screwing, it will seal inner barrel very strongly. There is no need force for installing collet nut, only easy force, otherwise the inner barrel will overturn in the Hop-Up chamber. Sign of best sealing is reduction of space in the collet.

This Hop-Up chamber has best performance with our CNC gearbox V3, because these parts are constructed for best performance together. They are also constructed for screwing together, so they hold in straight line with inner barrel without any air leaks. You can also use this Hop-Up chamber with common casted ZnAl gearbox.

retroarms-hop-up-chamber-ak-cnc-mechabox-v-iii -nahled

Hop-Up chamber can be also upgraded with CNC support cube, what supports Hop-Up chamber in weapons body and make reloading very easy. Video here.


Setting of Hop-Up is possible with setting lever in directions: front or back, as you need. Hop-Up spacer is not included, you can use from your own Hop-Up chamber, or you can buy upgraded silicone or teflon one.

This Hop-Up package includes

  • 1pcs Hop-Up chamber for AK (anodized, made from aircraft dural EN AW 7075)
  • 1pcs Setting lever (anodized, made from aircraft dural EN AW 7075)
  • 1pcs Pushing lever with cut for common spacers (anodized, made from aircraft dural EN AW 7075)
  • 2pcs Screw M2,5 x 3mm (chemical black layout, steel material 12050)
  • 1pcs Screw M3 x 12 mm (steel material with 8.8 strength, chemical black layout)
  • 1pcs Plastic C-Clip lock for AK (ABS material)
  • 1pcs Plastic pin (ABS material)
  • 1pcs Rubber O ring (vulcanized rubber)
  • 1pcs Collet nut (anodized, made from aircraft dural EN AW 7075)

We recommend to buy with this Hop-Up chamber our new spacers set, Hop-Up bucking and spare plastic C-Clip lock or collet nut.

Hop-Up chamber is delivered non-assembled – that means you have to put it together before use.


Our Hop-Up RetroArms bucking don’t need sealing with Teflon strap, because it has already surface sealing parts. We recommend using ethanol for installation of our bucking, it will lubricate it, but after installation, the ethanol will vaporize and bucking seals perfectly.

For easy assemble of spacer, we recommend to stick it to pushing lever with vaseline.

Warning! Don’t use oil or vaseline for lubrication of Hop-Up components, you can damage them and lose Hop-Up effect.