Design features and test data are summarized for a multishot switch and barrel of an electromagnetic launch system which has undergone trials at the Armament R&D Center (ARDC). The system features a 12 MJ homopolar generator, a 4.5 micro-H storage inductor and two circularly mounted parallel copper conductors separated by 2.5 cm. Tests focused on the performance of the opening switch with currents up to 500 kA. THe effects of the tests on the condition of the brush and on the operation of the switch are delineated, noting the deformations induced on the brush fingers by magnetic pressure, reducing contact force when the brush was in the input region of the switch. Design changes being implemented to alleviate the problem are outlined.