I have a KWA mp9 GBB I got this gun in a trade I’ve shot maybe a whole mag through it. It shoots very nice and very hard. I don’t know much about GBB so that’s why I’m selling it. I did test every mag none of them leak. Also comes with a extra barrel. Asking $120 OBO NO TRADES BUYER PAYS SHIPPING I can supply shooting videos if wanted all you gotta do is ask.