July 10, 2023
I can’t make forensic evidence “pretty.” Proceed if you are not squeamish, but I’ll cut to the conclusion: Never fire a bullet high up into the air!
This clearly falls under a broader rule we’ve all read: Be sure of your backstop and what is beyond. Why? There is no backstop in the sky!
I’ve heard people suggest that aerodynamic drag limits the terminal velocity of falling bullets to less-than-harmful levels. That is true only to a point and, based on century-old testing, understates the hazard. Falling bullets are dangerous and can even be lethal—I’ve held the evidence.
“Bullets from the Sky,” Chapter XX of Hatcher’s Notebook, covers falling bullets. Gen. Julian Hatcher described results of old Army firing tests with U.S. .30-caliber 150-grain FMJ flatbase bullets fired straight up. Due to aerodynamic drag on the way down, they returned at about 300 fps and fell base-first. That is about 30 ft-lbs of energy, half of what our military at the time considered necessary to produce a “disabling injury.” I believe that’s where some people stopped reading.
Deeper into the chapter, Hatcher pointed out that subsequent testing showed that bullets falling point-first fell faster and, predictably, that heavier bullets had greater terminal energy. Again, this is from true vertical, machine-rest firing. He did not address the arc produced by firing at some high angle other than perpendicular.
I’ve analyzed evidence that shows a real hazard exists. Three Crime Lab cases between 1981 and 1987 convinced me that falling bullets on a high-arc trajectory do not fit the pattern of those long-ago military tests.
Case 1: A person was found dead with a single, downward-tracking gunshot wound to the top of the head that penetrated the brain. My attention was piqued when I saw that police recovered a nearly identical, minimally deformed fired bullet on a sidewalk a half-block away. The investigator asked, “How fast does a bullet really fall if fired straight up?”
I identified both bullets as factory .357 Magnum 158-grain copper-washed lead SWCs. They had the same rifling characteristics and only minor nose deformation. I knew that load posted 1,220 fps to 1,260 fps from 4.0-inch-barreled revolvers. The sidewalk bullet had a flattened nose with an angle about 70 to 75 degrees from the horizontal.
Case 2: A woman was sitting up in bed in a mobile home when she felt a sudden pain in her lower-right abdomen. Her husband, thinking appendicitis, rushed her to the hospital.
The doctor discounted a “hot” appendix, and X-rays showed a bullet-shaped object near her appendix. The doctor removed the projectile and looked for an entrance wound; it was just ahead of her left armpit concealed by fatty tissue. I later identified the object as a .30-caliber 220-grain hunting bullet, and it was showing only minor scuffing to the nose. The victim recovered.
The investigating Texas Ranger found a bullet hole in the thin wall paneling by the bed and another high on the exterior sheathing. A dowel connecting the holes showed the bullet entered the bedroom at an angle of about 70 degrees from horizontal, and this was verified with a protractor.
Case 3: A man found a copper-jacketed bullet on his car’s hood, then noticed a serious half-inch dent in the roof. I identified the minimally deformed bullet as a .30-caliber rifle bullet, likely from a .30-30 rifle. Minor damage, indicating this one also fell nose-first, which left a flattened spot on the nose of about 70 to 75 degrees from horizontal.
That’s three cases with low-velocity bullets clearly falling nose-first. The detective working the fatality asked about impact velocity because a college physics professor told him a bullet fired straight up hits the ground at the same speed it leaves the ground. The detective knew intuitively that his “sidewalk” bullet did not hit the ground at 1,200+ fps.
The professor quoted the physics standard: a minuscule particle fired in a vacuum; the only force on the particle is gravity. We live in the real world; air resistance acts against falling objects to balance gravity’s acceleration, effectively stopping further velocity increase. Bullet shape, bullet stability, rotational forces, wind, and more are real-world effects on a bullet’s terminal velocity and trajectory.
Hatcher’s tests concluded using time-of-flight (TOF) measurements that, fired straight up, his flatbased bullets with center of mass (CM) near the base tended to fall base-first. Experimental .30-caliber 175-grain FMJ-BT bullets, whose CM was farther from the base, produced more TOF delay and variance, suggesting they were tumbling on the way down. As bullets reach very low velocity, the CM wants to go first; if the CM is closer to the bullet’s middle, the bullet may tumble as rotation stability decays.
True vertical firing is like a dead-end train track. A train stops and then must back up. Everything I observed suggested that a high-arc trajectory may permit the bullet to turn downward without completely losing all forward velocity and artificial stability from the rifling at the apex. In the cases I worked, the evidence was irrefutable—these bullets returned to terra firma nose-first.
What about high-arc injury or lethality? The “trailer case” was the easiest to assess.
I knew the specific .30-caliber 220-grain bullet could show some soft tissue expansion above 1,400 fps, so the bullet was likely going much slower. We don’t know how much slower. It penetrated the thin walls of a mobile home at 70 degrees plus about 15 inches of housewife. Further, there was no firing position for miles that would allow direct firing steeply down at the trailer. If this nose-on 220-grain bullet was doing 400 fps, that’s 78 ft-lbs. If it was doing 600 fps, it’s 175 ft-lbs.
I thought the case with the death was one of wrong place and time. The victim was still growing, and the bullet hit at the worst angle on the sagittal suture, a natural weak area of the skull in younger people. An inch or two in another direction would have created a different outcome.
There can be no presumption of a “soft” landing for any bullet fired high into the air. Even those fired from 90-degree vertical rests showed some effects of wind and spin. You cannot predict what forces a bullet will encounter, so don’t shoot at clouds!