The invention relates to an M16-series gunlock structure for a scattergun/shotgun. The M16-series gunlock structure comprises a striker, a striker spring, a machine frame assembly, a striker pin, a guide pillar and a machine head assembly, wherein the machine frame assembly comprises a guide pipe and a machine frame, the machine frame is arranged at the front end of the guide pipe, the machine frame and the guide pipe are connected into a whole through a machine frame connecting pin, the machine frame is provided with a spiral slot, the guide pillar is arranged in the spiral slot, and a through hole is formed in the machine frame and is communicated with the spiral slot; and the machine head assembly is arranged at the front end of the machine frame and comprises a locking body and a machine head body, the machine head body is arranged at the front end of the locking body, the locking body rotates relative to the machine head body, is connected with the machine head body through a connecting pin and is connected with the machine frame through the guide pillar, and the striker sequentially penetrates through central holes of the machine frame assembly, the guide pillar and the machine head assembly and is connected with the machine frame assembly, the guide pillar and the machine head assembly into a whole through the striker pin. By utilizing a separated machine head assembly, the locking body in the machine head assembly rotates, and the machine head body in the machine head assembly does not rotate, so that the strength of a gun barrel is not influenced by an extractor hook, the containing area of the gun barrel for cartridge cases is large, the deformation of the cartridge cases during the firing is little, and the firing safety is high.