A hand guard-to-barrel clamping system having provisions for internal clamping fasteners is disclosed. A hand guard assembly includes upper and lower members each having bores tangential to a longitudinal axis of the assembly. The bores are arranged such that fasteners can be inserted through the bores for securing the upper and lower members together, thereby clamping the hand guard assembly to the firearm. Such fasteners are internal to the hand guard assembly, which provides a slim design that is easier to hold.