A multiple carrier injection system (10) comprising an adapter (20) including at least one arm (22), a pen needle assembly (29) including a hub (30) retaining a needle (44), and a bullet (50) having a cover (58) to seal the bullet (50), the bullet (50) enclosing the hub (30) in a first position, wherein the arm (22) engages the adapter (20) to the hub (30), and the arm (22) causes the hub (30) to rotate within the bullet (50) to move the hub (30) into a second position.
