Abstract : The fundamentals are presented for a rational system of armor plate ballistic testing. The desirable properties of armor are first discussed. These are (1) high resistance to penetration, (2) freedom from back spalls, (3) freedom from cracking (shock failure). The theory of the ballistic methods by means of which these properties may be tested is then presented, and the relation of these methods to the non-ballistic methods is discussed. Finally, a criticism is given of the present ballistic specifications which are employed to test for these properties. It is found that the ballistic acceptance test could be improved by certain changes. These changes are for Resistance to Penetration Test, Resistance to Back Spall Test, and Resistance to Shock Failure.