Delayed blowback firearms with novel mechanisms for control of recoil and muzzle climb

A recoil control device for use in a firearm comprising a counteracting mobile mass;

• a mobile bolt configured to move from forward to rearward and a rearward to forward position during operation;
• the counteracting mobile mass configured to pivot from a cocked position to a second position, and having a surface to contact the mobile bolt during its movement;
• a receiver comprising a top main frame part configured to allow the movement of the mobile mass from a forward and cocked position to a rearward position while confining the mobile bolt within the axis of the barrel, the top main frame part of the receiver further comprising a forward extension assembly for connecting the mobile mass forward of the chambering end of a barrel of the firearm, the connection to the mobile mass allowing the mobile mass to pivot, wherein the mobile bolt comprises a projection that contacts the mobile mass at a first angled surface of the mobile mass during the movement of the mobile bolt, and upon firing of the firearm directs the pivoting movement of the mobile mass away from the barrel and wherein the movement of the mobile mass counteracts the recoil forces upon firing.