Hesitation-locked delayed blowback operation with rotating bolt
The 701 rifle uses an unusual cartridge short-recoil operation (not to be confused with recoil operation as it uses a fixed barrel) in conjunction with an annular chamber groove to seal the chamber. When firing, the cartridge sets back a short distance of 1.1-1.5mm to a stop and the bolt carrier continues to recoil due to inertia, unlocking the rotating bolt.[5]
^The World's Assault Rifles By Gary Paul Johnston, Thomas B. Nelson. "Development of the indigenous new Chinese military rifle had commenced early, in 1958. The Type 63 rifle was introduced first... it featured a combination of the SKS and AK design properties in one package. It was proven to be unsatisfactory and was withdrawn from service by the mid-1970’s. During the same period and amidst numerous other unknown Chinese small arms research projects, emerged the 66-136 experimental rifle. As its project name indicated, the development of the 66-136 began in 1966 and featured a unique delayed-blowback action that utilizes a two-
piece bolt assembly with a rear-mounted multi-lug rotating bolt."
