Abstract: An actuator for ejecting a store from an aircraft, with a pre-selected force vs stroke profile, is disclosed. The actuator comprises a cylinder and a fixed tubular member coupled to a source of fluid under pressure having a first array of orifices for flowing fluid into the cylinder. A piston assembly is provided, which is adapted to engage and eject the store. The iston assembly is slidably mounted within the cylinder and telescopically movable over the fixed tubular member from a first position, wherein the piston assembly covers a portion of the first array of orifices, to a second position, wherein the first array of orifices is uncovered. Typically, the pressure level of the source of fluid varies, generally as a function of the flow into the cylinder during the stroke of the piston assembly.