Liberator Airsoft goes into action with the King Arms TWS 9mm SBR GBB so you can evaluate how it performs. This GBB-R is more a PCC since it uses 9mm-style gas magazine. It is mainly made of metal with an M-LOK rail system for a handguard and has a 6.05mm inner barrel. It is able to use Glock-style gas magazines from Tokyo Marui, WE Airsoft, VFC, and ARMY Armament.