The beauty of the Top Japan Shell-Ejecting Blowback M4 AEG is the ability to customise it to whatever AR variant you can which means you get more different looking shell-ejecting AEGs. In this video, the latest custom work shows a KAC PDW being test fired. Whilst it may not be practical in airsoft skirmishes as costs of shells (plus the corresponding clean-up) would make it a deal breaker unless game rules require otherwise, for film/video makers, they got a more cost-effective gun prop.