The evike.com site has presented a short video showcasing an interesting hi-cap magazine for GBB pistols.
GBB pistol magazines are designed for custom AW Custom pistols. However, the manufacturer states that they will also work with replicas made by WE.
The presented magazine has a capacity of 350 BBs and a manual BBs feeding system. The manufacturer ensures that the adapters added to it make it possible to use the magazine with many types of pistols. At the moment, the magazine is available for GLOCK, M9, Hi-Cap and 1911 pistols.
The only thing remaining is to buy a 18C Glock :)