GATE EON CNC Hop-Up Chamber for M4/AR15 AEG

  • CNC Aluminium & POM construction
  • Various O-rings included
  • Rotary style adjuster - M4/AR15 AEG & HPA compatible

If you are building out your M4/AR15 AEG for maximum performance the Gate EON HOP-up unit is probably already on your list! This precise HOP-up unit is constructed from CNC machined aluminium and is a rotary style unit which applies pressure directly to the top of the HOP-up rubber/nub to minimise side-to-side deviation.

This unit is compatible with M4/AR15 AEGs and can also be used with HPA setups thanks to the included nozzle sleeve which perfectly centres the nozzle for maximum efficiency.

Full description


The Gate EON HOP-up unit follows the EON gearbox as part of Gates CNC internal parts range. The unit itself and the rotary adjuster are constructed from CNC machined aluminium and the HOP-up arm, redesigned C-clip, barrel spacer and HPA nozzle sleeve are made from CNC machined POM polymer to provide the precise tolerances necessary for optimal air seal and consistency down range.

Gate has redesigned the C-clip which centres the barrel and it is now made from CNC machined POM polymer to eliminate potential rotation, as is the HOP-up arm. The new C-clip has a protrusion in the bottom which interfaces with the indexing groove on AEG inner barrels, locking the barrel into a centred position and preventing rotation from occurring over time which will compromise accuracy and HOP-up effectiveness.

Included with the unit are plenty of spare O-rings which can also be installed over your inner barrel to seal any potential gap between the barrel spacer and the barrel itself. The unit itself has a pair of O-rings at the nozzle end and one on the feed chute to prevent BBs from falling out when you remove the magazine. Also included in the set is a nozzle sleeve to stabilise the nozzle when used with HPA engines. We all love the legendary Pro-win CNC HOP-up unit but has it now met its match?


  • CNC machined for ultra tight tolerances
  • Aluminium HOP-up unit & rotary adjuster
  • POM polymer barrel spacer, nozzle sleeve & HOP-up arm
  • Multiple O-rings included in the set - Install over the inner barrel to improve air seal
  • O-rings pre-installed at the nozzle end - Minimises air leaks
  • O-ring on the feed chute - no more BBs falling when you remove the magazine
  • Compatible with M4/AR15 AEG & AEG based HPA M4/AR15
  • Compatible with AEG inner barrels, HOP-up rubbers and nubs

Package Includes

  • Gate EON CNC Hop-Up Chamber for M4/AR15 AEG



Parts & Accessories Type
Internal Parts
Internal Part Type
Hop-Up Unit, Hop-Up & Parts,
Patrol Base - Warning Icon
Patrol Base - Warning Icon
Parts Fitting

Weight and Dimension

Weight KG Icon
Weight (KG)
Approx. 0.046kg


Colour Wheel Greyscale
Item Colour
Red, Cyan, Titanium,
Item secondary Colour
Violet, Red, Orange, Cyan,
Construction Icon
CNC Machined aluminium HOP-up unit & Adjuster. CNC POM C-Clip & HOP-up arm/tensioner. Rubber O-rings
Internal Part Construction
Polymer, Aluminium, Rubber,

Part Specific

Part for Power Source Type
Weapon Platform
  • AR
  • M4 / AR-15 / M16
  • Assault Rifle
Package Includes
  • O-Ring
  • Hop Unit

Electric Part Specific

Gearbox Icon
Gearbox Version
V2 Gearbox
Gearbox Version Compatibility Variant
Version 2

Size guide

Parts Fitting

Upgrades and Downgrades should only be undertaken by experienced players, or Airsoft Technicians. Please note, changing any internal parts of a weapon voids its warranty unless done in-house by our staff. 

Please ensure that when fitting parts the part purchased is the correct part, as once a part has been fitted we cannot accept return.

We do know that players love to tinker, so we're here to give you help should you require it, and if needed you can get in touch with our workshop for more help!

Unique Parts

Please note that some parts may be unique to a specific brand of weapon. For example: Parts for an ASG M4A1 may not fit an ICS M4A1.

Parts from the same brand typically have a high chance of fitting, though be warned, some replicas use unique parts, so please ensure the part will fit before you attempt to fit it.

If you require help with fitting any parts feel free to get in touch with us via our Contact Us Page.