The University of Texas at Austin Center for Electromechanics (UT-CEM) has been developing power converters for use with DC railguns. Special design rules have been established and demonstrated in the construction of laboratory hardware. Power converter requirements for electric guns are dependent on the characteristics of the power supply, load, circuit topology, and switching devices used. This paper discusses some of the design requirements particular to these converters and shows why simple figures of merit (FOMs) developed in the early design of a converter are not valid. An alternate FOM that can be used to compare converters and judge development progress is offered. Use of this FOM requires that an adequate amount of design work be completed on a converter before it is applied. The FOM is applied to previously demonstrated converters. Possibilities for near term development of devices and converters are examined and the potential results of that development are compared to past work by using the new FOM