Muzzle blast wave in small arms represents special problems for many applications. They may be attributed to supersonic flow of the discharged propellant gases from the barrel muzzle after the projectile departure. Herein, experimental investigation of controlled and uncontrolled blast wave has been carried out under different working and design parameters. Different silencer design theories were carried out, to control the blast wave in both subsonic and supersonic cases, which produced from automatic small arms. The pressure-time history of gases discharging from an automatic rifle 7.62 x 39-mm was measured for different mass of propellants. In addition, recoil force for the rifle without as well as with silencer and the projectile muzzle velocity has been measured. Results showed that, for different mass of propellants in ammunition and suitable design of silencer, the sounds could be reduced by about 90 percent. In addition, silencers reduced recoil energy by about 20 percent. Also, the silencer efficiency increases by decreasing blast wave pressure as well as mass of propellant of ammunition decreasing.