An autoinjector including a plunger for engaging with the bung, a collar located around the plunger, an insertion spring biasing the collar relative to the rear of the device, and a delivery spring biasing the plunger relative to the collar. The device further includes a stop feature defining the limit of axial movement of the syringe body through the housing, and a collar release mechanism for releasing the collar from the rear of the device to commence insertion and a plunger release mechanism for releasing the plunger from the collar while substantially preventing rearward axial movement of the collar, following insertion, to commence delivery of the medicament. Following release of the plunger from the collar, the plunger is configured to move axially and rotationally relative to the collar, the direction of rotation being changed one or more times with axial movement of the plunger.