A medicament delivery device includes distal and proximal housings; a medicament container having a slidable stopper partially, slidably arranged within the proximal housing; a plunger rod within the distal housing having a proximal end abutting the stopper; a driver within the distal housing operably connected to the plunger rod for driving the plunger rod and stopper toward the device's proximal end; and a priming device having a distal end including an engagement mechanism arranged to cooperate with an engagement mechanism at the housing's proximal end, an end wall abutting the container's proximal end, and a passage on the end wall. An engagement mechanism at the priming device's proximal end cooperates with a delivery member engagement mechanism. Distal displacement of the priming device relative to the proximal housing causes distal displacement of the container relative to the plunger rod, forcing proximal displacement of the stopper, thereby priming the container.