The Volokh Conspiracy
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Second Amendment Roundup: Cargill Bump Stock Argument in Supreme Court
The continuous, manual forward pressure on the handguard precludes “automatic” function.
On Wednesday, the Supreme Court heard oral argument in Garland v. Cargill, which poses the issue of whether a semiautomatic rifle with a bump stock is a machine gun. A machine gun is defined as "any weapon which shoots … automatically more than one shot, without manual reloading, by a single function of the trigger." 26 U.S.C. § 5845(b). If a gun fires automatically, i.e., without any manual manipulation, and it does so with a single function of the trigger – which could be a pull or a push – it's a machine gun.
In the very first two sentences of his opening statement for the government, Brian Fletcher unknowingly explained why a bump stock is not a machine gun. With a bump stock, one "places his trigger finger on the built-in finger ledge and uses his other hand to press the front of the rifle forward. As long as the shooter maintains that steady forward pressure the rifle will fire continuously…." What he didn't say is that if one just pulls the trigger but does not manually continue to push the handguard forward, the gun fires just one shot and stops firing.
A video is worth a thousand pictures. Watch how a machine gun fires. You can hold it with one hand and just pull the trigger, and it fires continuously until the magazine is empty. Now that's automatically by a single function of the trigger.
Not so with the bump stock. Try holding it with just one hand and pull the trigger. One shot and it stops firing. Look here at 3:15-4:48. Unlike the above machine gun, it did not continue firing even though the trigger remains pulled back.
Now watch a gun fire with a bump stock in slow motion, starting at 4:54. "So watch here as my hand pulls forward on the barrel of the gun," the narrator states. "The gunman fires and the recoil brings the trigger back to my stationary finger over and over, causing the trigger to be pulled again and again very quickly…." As the video shows, the trigger functions only once with each shot.
Or as Mr. Fletcher put it, pull the trigger and also "press the front of the rifle forward" and "maintain[] that steady forward pressure." That's not "automatic" by a "single function of the trigger." He also said that the firing is "automatic" because one "presses forward to fire the first shot, the bump stock uses the gun's recoil energy to create a continuous back-and-forth cycle." What happens if one stops pressing forward, even with the trigger pulled back? It stops firing.
For years, the Bureau of Alcohol, Tobacco, Firearms & Explosives (ATF) classified non-mechanical bump stocks as not being machine guns. Richard Vasquez was a top examiner at ATF's Firearms Technology Branch who was involved in this classification. As counsel for clients regulated or prosecuted by ATF, I knew Mr. Vasquez to be a tough but fair law enforcement officer who knew where to draw the line. He is now retired, and you can watch his explanation of why the bump stock is not a machine gun.
While the oral argument posed many hypotheticals, two real-life firearm designs came up. One was about the Atkins Accelerator, a mechanical bump stock that utilized a spring device to facilitate continuous fire. ATF initially approved the design as not being a machine gun, but later rescinded that classification and decided that it is a machine gun. Unlike the non-mechanical bump stock at issue here, one did not need to maintain continuous, forward pressure on the barrel or handguard to continue to fire.
The other device mentioned in the argument was the one referenced in US v. Camp (5th Cir. 2003), which involved an electrically-operated trigger mechanism. It "required only one action — pulling the switch he installed — to fire multiple shots," and thus was found to be a machine gun. No manual manipulation was involved. That's a far cry from a manually-operated bump stock.
Much was said in the argument about fast firing, even hundreds of rounds per minute (just a theoretical concept, because magazines only hold 30 or so rounds). But as Mr. Fletcher conceded, "we acknowledge this is not a rate-of-fire statute." Indeed, under the statutory definition, a machine gun could fire very slowly, but could still fire automatically with a single function of the trigger.
The transcript of the oral argument reveals a robust debate, but the statutory text is the elephant in the living room. A non-mechanical bump stock just isn't a machine gun.
