Following the Marushin PFC, MGC also developed CP-Blowback cartridge (CP is an MGC acronym for Cap Piston that relates to the "piston" design of the MGC cartridges) to change from open cartridge to closed type cartridge in 1982. Since then, all other modelgun makers adopted similar closed type cartridge design for their blowback models – Piston Push Cartridge from Tokyo CMC, Blowback CTG Cartridge from Kokusai, Piston Fire Cartridge from Hudson. Later various modelgun makers further enhanced the design with additional rubber O-ring to further enhance the air-seal inside the cartridge. It provides even better blowback performance especially for the Heavy Weight models. This finally comes to the current blowback cartridges: - CP-HW cartridge from MGC, New Piston Fire cartridge from Hudson, New Plug Fire Cartridge from Marushin, Evolution cartridge from Tanaka, etc.