Maple Leaf VFC/GHK M4 GBBR Hop-Up Chamber

The Maple Leaf hop-up chamber for VFC and GHK M4 GBBRs is a CNC-machined replacement for the original hop-up chamber in gas AR-15/M4 rifles from VFC and GHK. It also fits the Umarex/Elite Force HK416 and BCM Air MCMR gas rifles, which are based on VFC's system. The chamber is a drop-in part that replaces the original without modification.

The hop-up chamber holds the inner barrel and hop-up bucking in exact position, and that is what determines how consistently the BB gets its spin. Plastic or zinc factory chambers can flex during adjustment and over time, so the setting drifts. A CNC-machined aluminium chamber is stiffer and holds the adjustment, giving a more stable trajectory from magazine to magazine.

CNC aluminium, drop-in and stable adjustment

Five reasons to change the chamber:

• CNC-machined aluminium: Stiffer and more precise than the standard chamber, so the hop-up pressure on the BB does not change when the rifle warms up or takes knocks.
• Drop-in fitting: Dimensioned to the original chamber, so it fits without filing or modification.
• Holds the setting: The adjustment stays put between game days, so you do not have to find the right hop-up again every time.
• For VFC and GHK M4 GBBRs: Fits VFC and GHK AR-15/M4 gas rifles as well as the Umarex HK416 and BCM Air MCMR – e.g. the VFC BCM MCMR MK2 11.5" EVO GBBR.
• The basis for a precision upgrade: Combine with a precision inner barrel and a Maple Leaf hop-up bucking to get the full benefit of the rifle's range.

Maintenance and safety

• Fitting requires stripping the upper receiver. If you have not done it before, our workshop in Aulum, Denmark can do it for you.
• Remove the magazine and clear the rifle before stripping it.
• Clean the inner barrel and hop-up bucking when fitting, and set the hop-up again with the BBs you play with.