Abstract: Embodiments of the present invention provide solenoid plungers, solenoid actuators, and solenoid-actuated mechanisms, that provide for an adjustable stroke, adjustable rated force, and adjustable plunger extension that overcome the problems and issues associated with non-adjustable solenoid actuators. In accordance with an embodiment of the present invention, an adjustable solenoid plunger is provided that comprises a stem, a stem tail retention element adjustably coupled to the stem tail, and an armature having an armature bore, the armature adjustably coupled to the stem. The stem engages the armature bore and is adapted for advancement of the armature along at least a portion of the stem. The stem tail retention element is adapted to be advanced along the stem tail so as to adjust the extent of the plunger extending from the solenoid so as to adjust stroke, force, and plunger extension.