In regard to your column about the lack of danger from falling bullets [May 5], I enclose a recent article from the Los Angeles Times about the problem of falling bullets in LA around New Year’s and the Fourth of July. The article says there are numerous fatalities from such bullets. –Gordon Brooks, Los Angeles

Hmm. According to the article, doctors at King/Drew Medical Center, a major LA trauma center, say that between 1985 and 1992 they treated 118 people for falling-bullet injuries around New Year’s Eve and the Fourth of July. Thirty-eight of the victims died.

But read on. “There is some skepticism about the numbers reported by the King/Drew team,” the article continues. “The Los Angeles County Sheriff’s Department and the Los Angeles Police Department–which serve a vastly larger area–reported only about half a dozen deaths in the same period…. Other hospitals contacted by The Times … reported few cases.”

Granted, King/Drew handles a lot more gunshot cases than other LA hospitals. But the King/Drew doctors also used fairly liberal criteria to identify falling-bullet victims (no gunshot heard or weapon seen, wound consistent with bullet falling from above). Given how confused trauma victims and witnesses often are about what happened, the numbers reported are probably high.

Still, the question before the house wasn’t how many people got injured or killed by falling bullets. It was whether such things were possible at all. I said injure yes, kill no, provided the bullet was shot straight up. My source was Hatcher’s Notebook (1962) by Major General Julian S. Hatcher, a U.S. Army ordnance expert. Hatcher determined experimentally that a .30-caliber bullet shot straight up would return to earth at a speed of 300 feet per second and a force of 30 foot-pounds. “Previously, the army had decided that on the average an energy of 60 foot pounds is required to produce a disabling wound,” Hatcher wrote. “Thus, service bullets returning from extreme heights cannot be considered lethal by this standard.”

I quoted this statement without further investigation, which turns out not to have been so smart. (In my defense I note that the King/Drew doctors also cite Hatcher extensively, including his 60 foot-pound disabling-wound threshold, even though this figure is at odds with their other claims.) It appears a falling bullet’s kinetic energy (foot-pounds) alone is not a good predictor of the speed it needs to inflict a wound. B.N. Mattoo (Journal of Forensic Sciences 1984) has proposed an equation relating mass and bullet diameter that seems to do a better job. Experiments on cadavers and such have shown, for example, that a .38-caliber revolver bullet will perforate the skin and lodge in the underlying tissue at 191 feet per second and that triple-ought buckshot will do so at 213 feet per second. Mattoo’s equation predicts that Hatcher’s .30-caliber bullet, which has a small diameter in relation to its weight, will perforate the skin at only 124 feet per second. It’s easy to believe that such a bullet falling at 300 feet per second could kill you, especially if it struck you in the head. General Hatcher and I wish to apologize for any fatalities that resulted from our claims to the contrary. Come to think of it, I may have to reconsider my blithe assurances about dropping pennies off the Empire State Building, although I still think the penny’s light weight and propensity to tumble due to its shape would prevent it from reaching lethal speeds. Not that I’m advising anybody to experiment. As I often have occasion to tell the little researchers, if it seems real stupid it probably is.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.