Gascho D, et al. - Researchers identified bullets based on their metallic components and differentiated between ferromagnetic and nonferromagnetic bullets using CT. However all nonferromagnetic bullets significantly varied from ferromagnetic bullets, the important variations were entirely attributed to the higher dual-energy index (DEI) of solid Cu(Zn) bullets in comparison with that of all-lead bullets. The lead bullets with ferromagnetic, steel-containing jackets did not vary from the lead bullets with nonferromagnetic, non–steel-containing jackets based on DEIs obtained from the core and edge measurements. Using DEI calculations from CT numbers on an extended CT scale (ECTS), solid Cu(Zn) bullets could be clearly differentiated from lead bullets irrespective of the metallic components of the jackets. The DEIs based on the dual-energy pair 120 and 140 kVp seemed to be the most relevant for discriminating between these two types of bullets. In conclusion, this study gives new scientific knowledge relative to metals and their features at various tube voltage levels. The abilities of clinically approved dual-energy CT allow the distinction of bullets composed of low-atomic-number (Z) metals from bullets composed of high-Z metals through DEI calculations from CT numbers on an ECTS.