Maple Leaf Crazy Jet Inner Barrel Chamber Set for Hi-Capa Series

Maple Leaf
Code: ML-CH21H7CJ123
  • 70° HOP Bucking
  • For Hi-Capa Pistols
  • 6.02mm Inner Barrel

An aftermarket upgrade/replacement Inner Barrel and HOP Unit/Rubber for Hi-Capa Series Airsoft Pistols, specifically the Army Armament R601. This awesome package provides you with a Precision 6.02mm Inner Barrel, as well as a HOP Chamber, ML 70° Bucking and 'I-Key Delayer', to improve range, accuracy and precision.

The installation of this unit is relatively straightforward, and will be compatible with beginner/experienced techs.

Full description


This Crazy Jet Inner Barrel is an excellent upgrade for Hi-Capa Series Airsoft Pistols, and is relatively easy to install, requiring no tools and no previous experience. Care is obviously necessary when installing, so double check your process if you're unsure. In most cases, you will need to remove your Slide, remove the Recoil/Return Spring, remove the Outer and Inner Barrel Assembly, replace the old Inner Barrel/HOP Assembly with the new one and reverse the steps to re-install.

The unit has an overall length of 123mm, with an Inner Barrel length of 98mm from tip to HOP Chamber. This can help you determine if the unit will fit your Pistol. In some cases, the Inner Barrel will extend past your muzzle, which can be concealed by using a Mock Suppressor.

The unit is designed for Hi-Capa Series Airsoft Pistols, and perfectly fits the Army Armament R601. It will also fit the R603, R604 and KP05 models from Army Armament, but a Suppressor will need to be used to cover up the excess Inner Barrel (or you can ignore it; it's personal preference).


  • 6.02mm Inner Barrel
  • Precision HOP Chamber
  • Maple Leaf 70° Bucking
  • I-Key Delayer / Nub
  • Increase Range/Accuracy
  • For Hi-Capa Series Airsoft Pistols
  • Brass/Aluminium Construction
  • Perfectly Fits Army Armament R601
  • 98mm Inner Barrel -> HOP Chamber Length
  • 123mm Overall Length
  • Easy Installation
  • Ideal First Upgrade for Pistols
  • Minimal Experience Required

Package Includes

  • Maple Leaf Crazy Jet Inner Barrel Chamber Set for Hi-Capa Series



Internal Part Type
Hop-Up & Parts, Inner Barrel Accessories,

Weight and Dimension

Weight KG Icon
Weight (KG)
Approx. 0.05kg
Product Length
Approx. 12.3cm


Colour Wheel Greyscale
Item Colour
Construction Icon
Brass / Aluminium
Internal Part Construction
Aluminium, Brass,

Part Specific

Part for Power Source Type
Weapon Platform
Package Includes
  • Hop Rubber
  • Hop Unit
  • Inner Barrel

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.