Disclosed is an injection device including a body for receiving a syringe, a firing mechanism including a reaction component, a plunger configured to be axially displaced in a forward direction relative to the reaction component, and a drive spring located between the reaction component and the plunger for driving the plunger forwards upon activation of the injection device, wherein the reaction component provides a reaction surface for the drive spring. The device further includes a locking mechanism for locking the reaction component in a first axial position within the body, the locking mechanism being configured to release the reaction component upon a predefined forward movement of the plunger thereby allowing the reaction component to be driven in a rearward axial direction by the drive spring until it impacts against the body or a component secured to the body to thereby emit an audible indication of an end of dose.
