A toy projectile launcher having a projectile drum, a cocking slide, and a housing is disclosed. The projectile drum contains projectile holders that are adapted to hold a projectile, such as a foam dart. The cocking slide can be moved forward and backward. The housing houses a launch barrel and an air piston assembly. When the cocking slide is moved backward the air piston barrel moves backward, the launch barrel is moved forward away from a first projectile holder in the plurality to facilitate loading of a projectile into a holder. When the cocking slide is moved forward an air nozzle forms an airtight seal between the air piston barrel and the projectile holder, while the launch barrel is moved backward to form an airtight seal between the projectile holder and the launch barrel.