The ballistic performance was investigated with rigorous testing of the new armor steel alloy, a tempered variant and a benchmark material. Mechanical testing included Hopkinson pressure bar tests, high temperature, notched tests and standard quasi-static tensile tests. The combination of a commercial prototype cast steel and ballistic testing with NATO standard soft projectiles allowed a uniquely practical perspective when comparing results. The ballistic test procedure reported the same minimum thickness values, for STANAG level 1 kinetic energy threats, than the suggested values of the manufacturer and comparison to the new alloy was thus established. Dynamic material characterization is only accurate within the testing range. Using a single material model to predict critical strength and failure over large strain-rate and temperature ranges is only possible if the material response is consistent. A few scaling problems during specimen testing resulted in a challenging data set with subsequent numerical characterization difficulty. Ballistic performance was however found to correlate well with high strain-rate tensile tests.