A solenoid actuator is provided that includes a casing. A coil is positioned within the casing. A flux tube and axially separated pole piece are encircled by the coil. An armature is slidably mounted within bores of the flux tube and pole piece. The flux tube and pole piece are separated by a flux choke. A core shunt juxtaposes the pole piece from the flux choke. The core shunt, on major cross-sectional tubular thickness and a minor cross-sectional tubular thickness has an outer diameter of a curved shunt to provide enhanced performance stability.