An assembly (10) includes a forward unit (12) including a mounting portion (16) for mounting thereon a firearm, the forward unit (12) defining a projectile shooting axis (20), and a rearward unit (14) coupled to the forward unit (12). The rearward unit (14) includes a retractable buttstock (24) that has a retracted position and an extended position. In the extended position the rearward unit (14) is pivotable with respect to the forward unit (12) about a pivot axis (26) which is tilted relative to the projectile shooting axis (20).