Known for its gas efficient magazines and excellent GBBR platforms, GHK is admittedly late to the GBBR M4 bandwagon, but it stands apart from the rest when you compare the performance and external quality to its competitors.
With a steel bolt, barrel and control group, and aluminum receiver and a GHK made Keymod rail system, the material usage in the construction of this GBBR is entirely accurate to the weapon it aims to replicate. The steel parts exhibit a lighter grey than the treated aluminum and give the GHK Keymod MOD1 an excellent heft and balance. Durability will not be a problem with the quality construction and build quality exhibited by GHK on this replica.
Due to the steel bolt and GHK's modified negative pressure floating valve blowback system, when coupled with GHK V2 GBBR M4 magazines, the operation is amazingly reliable while performance and power consistency are excellent. If you've fired a GHK G5 and liked the kick on that, the kick on this GBBR is comparable, even given the increased weight of the body due to a heavier steel bolt that is still snappy and responsive on Top Gas.
The Hop-Up on this replica is easily accessible as long as you have a removable bottom rail like the one it comes with. The dial adjust is accurate and stiff enough to hold its adjustment even given the immense recoil of the platform. Speaking of recoil, be sure that any optic you mount on this is of decent quality with ample shock resistance to prevent zero shift. See out article review on 'The Price of Accuracy' in the REVIEWS section for more on this.
The Keymod MOD1 GBBR is an excellent performance gas blowback rifle replica that looks the part and performs better and with more reliability than probably any other GBB M4 available on the market. GHK took their mastery of gas efficiency and professional understanding of GBB mechanics and have produced a real nominee for any 'Best GBBR award'.