This invention relates to firearms of the type disclosed in my prior U.S. Pat. No. 3,424,053, granted Jan. 28, 1969, in which the principal parts such as actuating sleeve, receiver, frame and breechblock are made from cylindrical extruded metal tubing and metal rods. The combination of a cylindrical actuating sleeve, breechblock, frame, receiver, floating power cylinder, ratchet counter firing mechanism and other incidental parts are used to form a new action for automatic firearms.This new action consists of a cylindrical sleeve carrying a floating power cylinder and functioning as an extractor port seal, breechblock stop and to actuate the ratchet firing counter. The above-mentioned parts and the breechblock lend themselves to manufacture by the use of automatic lathes and screw machines.The use of an actuating sleeve and floating power cylinder results in a favorable mass ratio, which results in a reliable firearm.