Just posted today by WGC Shop is a test of the GHK AR/M4 Gas Blowback Prototype. We have seen photos of this previously and in fact this project has been in the works since they released an AR GBB Kit in 2012. Now they will soon be releasing a fully completed M4 GBB which we hope would have a heavy kick just like their well-received GHK G5 GBB which uses an AR gas magazine.