RESUMEN
BACKGROUND: Many new types of expanding or fragmenting handgun ammunition have been developed. Knowledge of these unusual bullets may aid in the management of patients and their wounds. METHODS: Eleven different expanding or fragmenting .45 caliber bullets and a nondeforming, full metal jacketed bullet for comparison were fired multiple times from the same handgun into both a water reservoir and ordnance gelatin. Performance was observed and recorded. Muzzle velocities were measured using a chronograph. Bullets were disassembled and cross-sectioned to facilitate inspection. RESULTS: The distinguishing surface and internal features of each bullet are described. When fired into water and ordnance gelatin, the bullets reliably expanded to 1.49 to 1.89 times their prefired diameters. Rates of kinetic energy loss of bullets of equal mass fired into ordnance gelatin were plotted. Full metal jacketed bullets penetrated twice as deeply as deforming bullets. Jackets of some of the expanding bullets separated when fired into water. CONCLUSION: Expanding/fragmenting bullets produce larger, shallower wounds than do full metal jacketed bullets. Recognition of the wound and roentgenographic appearances of these unusual bullets will help the trauma surgeon to properly treat gunshot victims. Because of the occurrence of jacket separation in water, ordnance gelatin should be used for optimal evaluation of bullet performance.