DO999 does an assembly of a Russian bullpup shotgun replica, based on the Tokyo Marui SAIGA-12 GBBS, using a Groza-12 Conversion Kit from ITP, concluding with a firing demonstration. The process involves unboxing the kit, attaching the top rail and front sight, and removing existing components like the receiver cover, recoil spring, trigger group, and pistol grip. The new trigger mechanism is then assembled and installed, followed by attaching the sling mount, rear stock adapter, and the bullpup stock itself. Completing the build involves adding a side rail system, front grip, mock suppressor, and a red dot sight, before finally loading the magazine and demonstrating the airsoft shotgun's functionality.