The Special Weapons MK-760 is a commercial semiautomatic firearm patterned after the Smith & Wesson Model 76, but it was not manufactured by Smith & Wesson. It was produced by Special Weapons, and the MK-760 name refers to that commercial reproduction/variant. In general, the MK-760 has the characteristic M76-style: Tubular receiver and simple stamped-metal construction 9x19mm chambering M76-pattern magazines External appearance closely resembling the original S&W 76 Semiautomatic-only commercial configuration on the version you're describing So if you're trying to identify or describe a firearm marked "SPECIAL WEAPONS MK-760," the appropriate description is a semiautomatic commercial reproduction/variant of the Smith & Wesson Model 76, rather than an actual S&W-produced Model 76. If you give me the exact markings on the receiver (or a photo), I can help distinguish the particular Special Weapons MK-760 variant and its approximate production period.