The ballistic performances of Ramor 500 and Ramor 550 armor steel plates were experimentally and numerically investigated at various conditions against 7.62 mm bullets. The experimental part of the study consists of the monolithic plate, double-layered plate, and oblique plate. For the monolithic plates, 6.7 mm thick Ramor 500 and 6.2 mm thick Ramor 550 were used. Plates were perforated and the failure mechanism of petalling was observed. For the double-layered plates, 6.7 mm thick Ramor 500 and 6.2 mm thick Ramor 550 were layered at two different ordering structures. It was found that Ramor 550 as facing plate and Ramor 500 as backing plate exhibit better ballistic resistance than the configuration of the opposite layering order and the main failure modes of the targets were plugging and bulging. For the oblique plates, 4.5 mm thick Ramor 500 plates were impacted at 0 degrees, 30 degrees, and 60 degrees impact angles. The result showed that the ballistic resistance of plates increased as the impact angle was increased. (C) 2021 Karabuk University. Publishing services by Elsevier B.V.