Patent ID: 8689477

Claim:
A top opening, modular top rail, multi-rifle adaptable free float rail accessory system in combination with a firearm comprising: a firearm having a gas piston operating system, a receiver, a barrel, and a barrel nut including a cylindrical portion terminating at a forwardly directed end with a radially outwardly directed flange, the barrel nut coupling the barrel to the receiver; a free float rail accessory system having a bottom portion with a forward end and a rearward end, an inner surface of said bottom portion having a groove formed therein, perpendicular to a longitudinal axis of said bottom portion and spaced from the rearward end, the groove receiving the flange of the barrel nut to align the bottom portion with the receiver and to prevent longitudinal movement of said bottom portion; a clamp assembly engaging a top part of the barrel nut and configured to attach to the rearward end of the bottom portion, the clamp assembly including a clamp element having a central semicircular recess receiving the cylindrical portion of the barrel nut, and a surface which is constructed to abut the radially outwardly directed flange of the barrel nut; an anti-rotational device having an inner surface configured to receive said barrel nut, two rearwardly directed flanges on opposite sides of the firearm receiver, and a front edge, said front edge abutting the flanged end of said barrel nut when the clamp assembly is secured to the rearward end of the bottom portion, said flanges preventing rotational movement of the free float rail accessory system; a top portion having a top section and opposing side sections extending therefrom and each terminating at an edge, the top portion and the bottom portion encircling the barrel when coupled together, said top portion being removably coupled to the bottom portion; and a manually installed component oriented to extend parallel with a longitudinal axis of said bottom portion, said component configured to removably secure and unsecure said top portion to said bottom portion when manually manipulated by a user without the use of a tool.