US Patent 7162822 Collapsible buttstock for firearm

A buttstock for a firearm having a buffer recoil mechanism is collapsible and adjustable. The buttstock includes a lower receiver extension having a bore therein that fits over the buffer recoil mechanism, the lower receiver extension being fixed to the buffer recoil mechanism; a buttstock body having a bore therein for receiving the lower receiver extension; a locking lever disposed along the bottom edge of the buttstock body; a locking pin disposed in the buttstock body and in the locking lever; and a compression spring disposed around the locking pin for biasing the locking pin towards the lower receiver extension.