The conventional understanding of particle impact ignition relies on the following principles: (1) flammable particulate (except in the case of titanium and aluminum target materials); (2) gas velocity greater than 100 ft/s; (3) impact point ranging from 45° to perpendicular to the path of the particle; and (4) a flammable target material. To test assumptions about whether particulate flammability is necessary for particle impact ignition of less reactive target materials such as Inconel 718, testing was performed with inert particulate. Supersonic particle impact testing was conducted with heated gas and 1,500-µm sapphire particulate on various target materials: 304 stainless steel, wrought and selective laser-melted Inconel 718, and Monel 400. Post-test characterization of impact craters was performed on each type of metallic target sample, including surface characterization by light optical microscopy and scanning electron microscopy with energy dispersive spectroscopy. Full consumption of the stainless steel and wrought Inconel 718 targets was noted to occur with sequential impacts. This paper discusses the results of testing and gives recommendations for updating the understanding of the particle impact ignition mechanism.