Our take: This factory original spare King Arms Colt M4 Gas Blowback Rifle spare magazine is manufactured by GHK, and is compatible with all GHK GBB Kit equipped M4 airsoft gas blowback rifles. This spare King Arms GBB Colt M4 magazine can use HFC134a gas (low pressure gas), green gas, or propane with silicone oil. The magazine has a large gas reservoir capable of holding more than enough gas to empty your entire magazine. The magazine has a 40 round capacity, which is perfect for most MilSim airsoft games. This magazine is constructed entirely of high grade metal and has a reinforced nozzle and magazine feeding lip. This is a must have if you are using the King Arms Colt M4 GHK GBB Kit Gas Blowback Rifle!
Note: Filling the magazine OVER 40 rounds can damage your airsoft GBB rifle.
Compatibility: 100% Compatible with the King Arms Colt M4 GHK GBB Kit Gas Blowback Rifle
Magazine Capacity: 40rds
Construction: Full Metal
Gas Compatibility: HFC134a, Green Gas, Propane w/ Silicone Oil