Patent ID: 8281704

Claim:
A firearm comprising a counteracting mobile mass configured to move in reaction to firing and to counter the recoil forces upon firing, the firearm further comprising: a barrel defining an axis of the barrel, the barrel having a cartridge chambering end and a firing end; a mobile bolt configured to move along the axis of the barrel from forward to rearward and a rearward to forward position during operation of the firearm; a the counteracting mobile mass further configured to pivot from a upward and cocked position under the barrel to a lower 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-most 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 fixing the barrel and for connecting the mobile mass below the barrel and forward of the chambering end of the barrel, 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, and upon firing of the firearm directs the pivoting movement of the mobile mass downward away from the barrel and wherein the downward movement of the mobile mass counteracts the recoil forces upon firing.