US Patent 7793452 Modular fore-end rail assembly with locking mechanism

A modular fore-end rail assembly for a firearm is disclosed. The assembly includes an upper handguard having forward and rearward ends. A dovetail rail extends between the forward and rearward ends. Opposing sidewalls extend outwardly and downwardly from the dovetail rail, respectively. The sidewalls terminate in mounting channels. The rearward end includes a first clamping member. A clamp is removably secured to the rearward end and cooperates with the first clamping member to engage a barrel nut of a firearm. The clamp has an exterior surface including a slidable locking pin movable between a locked position and an unlocked position. A lower handguard includes sidewalls that extend outwardly and upwardly. The sidewalls terminate in mating formations that are configured to be slidably received in the mounting channels. A lock aperture is provided at a rearward end of the lower handguard. The locking pin may be slidably engaged with the lock aperture to selectively retain the lower handguard to the upper handguard.