Rifle handguard system
An improved handguard for AR type rifles is shown. The handguard system uses an offset cam with a dual tapered side surface that engages a tapered circumferential groove on the barrel nut. Tightening the cam in place forces the receiver end of the handguard to clamp simultaneously against the barrel nut and against the front edge of the upper receiver of the rifle.
1. A handguard system for a rifle having an upper receiver, the handguard system comprising:
a) a handguard body including a tab extended from a bottom edge at a receiver end of the handguard body, the tab including a cutout to the side and shaped to receive a triangular shaped cam, and,
b) the triangular shaped cam having a front surface, a back surface, a top and a bottom, and a first side surface and a second side surface and a hole extending from the front surface through the back surface for receiving a cam screw, and, a center of symmetry located vertically in the front surface, and, the first side surface having a tapered region at the top, the tapered region being tapered from the front surface to the back surface along two axes, and,
c) a barrel nut having a circumferential groove, the circumferential groove having a first tapered surface and a second tapered surface, and, the center of symmetry of the front cam surface is offset from the center of the groove when the handguard is fit over the barrel nut and the cam is inserted in the cutout, and,
d) when the handguard body is fit over the barrel nut and the cam screw is inserted through the hole, engaging a threaded hole in the tab, and, tightened, the tapered region of the cam engages the first tapered surface of the groove and causes the body of the handguard to simultaneously be pressed against the barrel nut and against the upper receiver thereby aligning and securing the handguard body against the upper receiver of the rifle.
2. A triangular shaped cam used in securing a handguard to a barrel nut, the barrel nut having a circumferential groove, and,
a) the cam having a front surface, a back surface, a top and a bottom, and a first side surface and a second side surface and a hole extending from the front surface through the back surface for receiving a cam screw, and, a center of symmetry located vertically in the front surface, and, the first side surface having a tapered region at the top, the tapered region being tapered from the front surface to the back surface along two axes, and,
b) the circumferential groove having a first tapered surface and a second tapered surface, and, the center of symmetry of the front cam surface is offset from the center of the groove when the handguard is fit over the barrel nut and the cam is inserted in the cutout, and,
c) the tapered region of the cam engages the first tapered surface of the groove and causes the handguard to simultaneously be pressed against the barrel nut and against an upper receiver of a rifle to which the barrel nut is attached, thereby aligning and securing the handguard against the upper receiver of the rifle.