In a previous paper, we presented a scaling law for the ballistic-limit velocity for the 7.62 mm APM2 bullet and aluminum armor plates. This scaling law predicts that the ballistic-limit velocity is proportional to the square root of the product of plate thickness and a material strength term. In this note, we present additional ballistic data from the US Army Research Laboratory (ARL) and the Norwegian University of Science and Technology (NTNU) to show that this scaling law is accurate for eight aluminum alloys, plate thicknesses from 10 to 60 mm, and yield strengths from 51 to 414 MPa
