Design and testing of solid armatures for large-bore railguns

A solid metal railgun armature called the Fishbone has been designed and tested at significant velocity, in both square- and round-bore configurations. The name `fishbone´ describes a structure consisting of multiple, independent, compliant contacts. Primary measures of success are low muzzle voltage and post-shot bore integrity. Experiments at armature velocities in excess of 1.9 km/s have resulted in smooth muzzle voltage traces with peak values of 50 to 100 V and negligible bore damage. Design and performance issues important to the successful launch of a solid armature and the features of the Fishbone that address them are discussed. These issues include contact maintenance and gun stiffness, armature compliance, wear, thermal and structural integrity and materials selection. Shot data included are current, velocity, muzzle voltage, and post-mortem physical analysis