Maj. Nidal Malik Hasan, the army psychiatrist accused of gunning down 13 people at Fort Hood on Thursday, managed to fire 100 rounds with a semiautomatic handgun between the start of his rampage at 1:20 p.m. and the time he was shot at 1:27 p.m. How many rounds can a handgun shoot in seven minutes?
At least 1,500. Modern semiautomatic weapons can discharge a round and load the next bullet into the chamber faster than even the nimblest of fingers can pull the trigger. FBI studies have shown that a novice can fire three shots in less than a second, and a trained shooter can double that. (Two of the officers in the 1999 Amadou Diallo shooting emptied their 16-bullet magazines in about four seconds.) That means an experienced gunman can fire off a 20-round magazine—the likely capacity of Hasan's gun—in 3.3 seconds. Reloading takes under two. You just press the magazine release button with your shooting hand and insert the new magazine into the grip with your offhand. * Experts holster extra ammunition on the side of their nonshooting hand to speed the exchange and can have the new magazine loaded before the empty one hits the ground. So each 20-round magazine would take no more than 5.3 seconds, including time to reload. That means you could fire off 1,575 shots in seven minutes—provided you were carrying 79 magazines on your person.
There are a few potential snags. Each magazine is over an inch wide, and you probably couldn't lug around more than 25 magazines on your belt. It might take two minutes to get through those 500 bullets; at that point, you'd need someone to hand you more ammunition. In addition, each gunshot creates fouling—a combination of unburned powder and metal filings from the casing and bullets—which can accumulate and cause the gun to lock up. Overheating would also be an issue: A pistol can get so hot from the exploding gunpowder and the bullet screaming through the barrel that the cartridges ignite without the trigger being pulled, a situation called cook-off. The heat might also cause the barrel to deform slightly, decreasing accuracy.
With or without a laser-straight barrel, aiming is an issue when you're firing as fast as you can. Hasan minimized that problem by choosing the FN Herstal Five-Seven Pistol. The relatively new gun—it hit the market in the late 1990s—uses longer, skinnier, and lighter bullets than more popular handguns like the Glock 9 mm. This means there is less recoil, so a shooter can recover his aim between shots.
The slowest handguns on the market are revolvers, which hold five or six bullets in multichambered cylinders. The original revolvers were single-action—in between shots, the user had to cock the gun with either the thumb of his shooting hand or the thumb or palm of his nondominant hand. (Still, a skilled shooter could squeeze off five or six rounds pretty quickly.) Modern double-action revolvers don't require this extra motion, but the triggers are much stiffer than those of semiautomatic pistols—12 pounds of finger force is required, as opposed to five or six. Reloading is also more complicated. Placing the bullets into the chamber individually can take several seconds. A speed loader, a plastic device that lines up over the chambers and drops the bullets in at the turn of a knob, is faster but still can't match the speed of a semiautomatic pistol.
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Explainer thanks Ken Cooper of THT of New York and Edward Robinson of George Washington University.
Correction, Nov. 10, 2009: The original version mistakenly referred to inserting an empty magazine into the grip. (Return to the corrected sentence.)
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