An assembly for mounting a handguard to a firearm utilizes a biasing element disposed intermediate the barrel nut and the interior end of the handguard and a clamping element also disposed intermediate the barrel nut and the interior end of the handguard but positioned opposite the biasing element about the perimeter of the barrel nut. One or both of the biasing element and clamping element have multiple surfaces which mimic portions of the exterior profile of the barrel nut to prevent any of longitudinal, axial, or radial misalignment of the handguard relative to the axis of the firearm barrel.