Patent ID: 8757044

Claim:
An arm assembly for a firearm, the arm assembly comprising: a) an arm, the arm having a pintle housing, the arm pintle housing having an interior comprising a socket and an exterior; b) a pintle disposed in said socket, the pintle having a groove that extends about said pintle at a first pintle height, and a plurality of substantially circular recesses disposed about said pintle at a second pintle height; c) a rotatable adjustment knob attached to said pintle housing and rotatable relative to said pintle housing; d) a moveable collar comprising a tongue, said moveable collar operably connected to said adjustment knob, wherein rotation of said adjustment knob causes said tongue to engage said groove in said pintle and inhibit said pintle from rotating in and retracting from said socket; and e) a locking pin assembly comprising: i) an assembly shaft having a forward end, a rear end, an assembly shaft length extending from said forward end to said rear end and a generally hollow interior; and ii) a locking pin configured to engage at least one of said plurality of substantially circular recesses in said pintle and inhibit said pintle from rotating in said socket, wherein said locking pin is disposed within said assembly shaft and has a forward end and a rear end, said forward end being adapted to releasably engage said pintle.