An auto-reset dose release firing system for use in a medicinal inhaler, the system comprising: an axis that defines an axial direction that extends along or parallel to the axis; a stored energy device; a first plunger movable in the axial direction between a first position, a second position, and a third position, wherein the first plunger is configured to be operatively coupled to a medicament canister of the medicinal inhaler to travel axially with the medicament canister and to actuate a dose release valve of the medicament canister when the first plunger is in the second position; and a second plunger movable in the axial direction between a first position and a second position, wherein the second plunger is not configured to be coupled to the medicament canister, wherein the second plunger is positioned to be driven by the stored energy device of the firing system from its first position to its second position when the stored energy is released, wherein the first plunger and the second plunger are movable with respect to one another in the axial direction and are shaped to define an evacuable chamber therebetween; wherein the firing system has a primed state, a fired state and a reset state; wherein, when the firing system is in its primed state: stored energy of the stored energy device is not released; and the first plunger and the second plunger are separated by a first axial distance and the first plunger and the second plunger are each in their respective first positions, wherein the first axial distance is at least zero; wherein, when the firing system is in its fired state: the stored energy of the stored energy device is released; and the first plunger and second plunger are separated by the first axial distance and the first plunger and the second plunger are each in their respective second positions; wherein, when the firing system is in its reset state, the first plunger and the second plunger are separated by a second axial distance, the second plunger is in its respective second position, and the first plunger is in its respective third position, wherein the second axial distance is nonzero and is greater than the first axial distance; and wherein the evacuable chamber includes a vent which is: dimensioned to provide a reduced air pressure in the evacuable chamber when the first plunger and the second plunger are moved from their respective first positions to their respective second positions when the firing system passes from its primed state to its fired state; and further dimensioned to allow air ingress at a desired rate to move the first plunger from its second position to its third position when the firing system automatically passes from its fired state to its reset state. an axis that defines an axial direction that extends along or parallel to the axis; a stored energy device; a first plunger movable in the axial direction between a first position, a second position, and a third position, wherein the first plunger is configured to be operatively coupled to a medicament canister of the medicinal inhaler to travel axially with the medicament canister and to actuate a dose release valve of the medicament canister when the first plunger is in the second position; and a second plunger movable in the axial direction between a first position and a second position, wherein the second plunger is not configured to be coupled to the medicament canister, wherein the second plunger is positioned to be driven by the stored energy device of the firing system from its first position to its second position when the stored energy is released, wherein the first plunger and the second plunger are movable with respect to one another in the axial direction and are shaped to define an evacuable chamber therebetween; wherein the firing system has a primed state, a fired state and a reset state; wherein, when the firing system is in its primed state: stored energy of the stored energy device is not released; and the first plunger and the second plunger are separated by a first axial distance and the first plunger and the second plunger are each in their respective first positions, wherein the first axial distance is at least zero; wherein, when the firing system is in its fired state: the stored energy of the stored energy device is released; and the first plunger and second plunger are separated by the first axial distance and the first plunger and the second plunger are each in their respective second positions; wherein, when the firing system is in its reset state, the first plunger and the second plunger are separated by a second axial distance, the second plunger is in its respective second position, and the first plunger is in its respective third position, wherein the second axial distance is nonzero and is greater than the first axial distance; and wherein the evacuable chamber includes a vent which is: dimensioned to provide a reduced air pressure in the evacuable chamber when the first plunger and the second plunger are moved from their respective first positions to their respective second positions when the firing system passes from its primed state to its fired state; and further dimensioned to allow air ingress at a desired rate to move the first plunger from its second position to its third position when the firing system automatically passes from its fired state to its reset state.