Comrade Quiche Airsoft got the WE Airsoft Keltec PLR-16 GBB  to bring to action a gas guns only airsoft game... "Order 66 & Heavy Recoil Club played a friendly game with the theme: 'Gas guns only'.  With 40 players total, it was our largest Gas-Guns-Only private game!

This included GBB/NBB pistols, GBB/NBB rifles, and spring powered guns. Tapped gas guns were also OK. As long as the replica started life as a gas gun, you are good to go (No HPA'd AEGs)."