They are selling the durability of their bolt system, however, not fair they using air pump on the mags (dry air) is the most stable air pressure means unlike red dot or top gas! But it seems to us that the CNC machining is of high quality, thus, maybe richmaninokatsu M4! One more damn choice for Hong Kong GBB rifle fans. WA system require its own design magazines! They better product real-thickness size M4 GI 30~50 rounds CO2 magazines (can slot into modified Mapuxl P Mags like the VVE GBB M4 mags), because, most of GBB fans will stop play VVA system due to magazine problems! VVE have no problem with VVE GBB M4 rifle and their magazines improved a lot! If We don't see any improvement of VVA mags, Chiu&Pee mags and Chi..na made GBB mags we will STOP investing VVA system again.