A calculational method for obtaining detailed armature parameters associated with railgun launchers has been developed. Calculated parameters are obtained for device features and operating conditions supplied as input parameters. The model was validated by reproducing several sets of experimental data from a variety of devices. Model parameters associated with armature mass loss and plasma axial profiles were obtained as part of anchoring the calculations. The data included complete sets of dynamics, armature lengths, and muzzle voltages for each case studied. From the calculations, several differences between the various types of armatures (i.e. solid, hybrid, and plasma) and bore sizes were identified and found to account for the resulting performance features.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>