An auto-injector for delivering a liquid medicament includes a housing arranged to contain a syringe with a piston for sealing the syringe and displacing the medicament, the housing having a proximal end and a distal end and a telescopic plunger unit arranged between the piston and the proximal end of the housing, the telescopic plunger unit comprising a telescopic frame and a spring element surrounding a plunger element. The plunger element is fixed to a base of the telescopic plunger unit and the spring element is held in an initial compressed state by a compressive force exerted by the base of the telescopic plunger unit. When the spring element is released, a tapering profile of the telescopic frame is configured to provide varying friction with extension such that resistance to telescopic extension decreases as spring force provided by the spring element decreases with increasing extension of the telescopic plunger unit.
