This paper describes an experimental investigation of ballistic perforation of thin duralumin plates struck by the standard 7.62 mm bullet. It also simulates experimentally obtained results using Ravid-Bodner two-dimensional analytical model (1983) for plates exhibiting plugging failure. Five impact velocities ran-ging from 220 to 700 m/s and plates of 1.6, 3 and 4 mm thickness are considered. The plates mechanical properties are also changed by a heat treatment procedure which consists of solution hardening followed by artificial ageing. It is found that the changes in projectile velocity drop and in its energy loss with impact velocity are qualitatively similar. It is also found that the penetration resistance of treated plates is generally greater than the as-received ones, although the former have smaller yield and ultimate strengths. The specific energy loss increases with the increase of plate thickness for the as-received duralumin plates, while it first decreases and :h,-en increases for the treated plates. Predicted responses employing the five-stage analytical model of Ravid and Bodner are also obtained and compared with experimentally obtained responses. Good agreement is generally obtained.