The results of a series of experimental tests on the local loading of circular plates resting on a ring support are presented. Both quasi-static and impact loading tests were performed using hemispherically-tipped and flat-ended cylindrical indenters. The contrasts between the quasi-static and dynamic responses are examined as are the differences produced by the different indenters. The effects of local indentation on the overall quasi-static response of the plate are investigated, and the errors that arise from neglecting these effects when applying rigid, perfectly-plastic plate theory to the problem are highlighted. The maximum energy absorbing capacity of the plates when subjected to impact from hemispherically-tipped and flat-faced projectiles are determined experimentally and compared with the available empirical formulae. Two empirical formulae for the prediction of the energy required to perforate a steel plate with a hemispherically-tipped projectile, adapted from the well-known S.R.I. and Neilson formulae for flat-faced projectiles, are proposed.