Firearm stock with adjustable length of pull

A method of installing a firearm stock, the method comprising:

• providing a firearm with a beam extending longitudinally along a beam axis, the beam defining a plurality of recesses and a clearance channel along a bottom surface;
• providing an adjustable rifle stock comprising:
• a stock body having an upper body portion and a lower body portion, the upper body portion defining a beam opening sized and shaped to slidingly receive a portion of the beam;
• a lever attached to the stock body below the upper body portion, the lever pivotable between a locked position and a first unlocked position, and movable between the locked position and a second unlocked position;
• and
• a locking mechanism between the lever and the beam, the locking mechanism operable between a locked condition and an unlocked condition in response to movement of the lever among the locked position, the first unlocked position, and the second unlocked position;
• shifting the lever downward and forward to the second unlocked position, thereby moving the locking mechanism to the unlocked condition;
• sliding the stock body onto the beam so that the beam is received in the beam opening;
• and
• returning the lever to the locked position, thereby engaging the locking mechanism with the beam.