The twin barrel design refers to the presence of two parallel barrels within the firearm. This configuration allows for increased firepower and faster shooting, as two rounds can be fired simultaneously or in quick succession. It is often used in applications where a high rate of fire is desired, such as in certain military or law enforcement scenarios. The products use 38CrMoAlA material, the surface hardness after hardening HV≥ 920. Finish machining and Nitriding, Nitrded case depth: 0.5-0.8mm. The design of this screw is suitable for SPC production. Whole inner hole of barrel (except feeding part) use 6-8mm SKD bushing. This material can solve the wearing problem and can increase the working life so that save the cost of customers.