Nerf Slingfire

The SlingFire is the first clip system Zombie Strike blaster. It features an integrated shoulder stock and one tactical rail, as well as an integrated iron sight and three sling points.

Unlike most blasters, the SlingFire's firing trigger is in the shape of a real blade trigger, likely because of the lever-action priming mechanism. Notably, it is the second Nerf blaster to be able to fully function with the jam door open, the first being the Revonix360. The shoulder stock can be removed by removing the screw in the center of the brown section of the stock that is above the trigger and sliding the stock straight back.

Source: http://nerf.wikia.com/wiki/SlingFire