Supreme Court blows it on bump stocks

On October 3, 2022, the Supreme Court rejected the cases Aphosian v. Garland and Gun Owners of America v. Garland.  This action upheld the ban on "bump stocks" imposed by President Trump after the Las Vegas shooting in 2017, defining "bump stocks" as "machine guns."

Is a bump stock a machine gun?  What is a bump stock?  What is a machine gun?

Here is the definition of a machine gun:

Any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot without manual reloading, by a single function of the trigger.

The frame or receiver of any such weapon.

Any part designed and intended solely and exclusively or combination of parts designed and intended for use in converting a weapon into a machine gun, or

Any combination of parts from which a machine gun can be assembled if such parts are in the possession or under the control of a person.

The operative phrase is found in the first paragraph: "by a single function of the trigger."

(For the sake of credibility, this author was a machine-gunner in the 25th Infantry Division in the 1980s.)

When you cock a machine gun, the mechanism that locks the bolt or hammer back is a latch called the "sear."  When you pull the trigger, the sear drops, allowing the bolt or hammer to fly forward, firing a cartridge.  The recoil from the discharge (or, in a gas-operated system, the expanding gases) forces the bolt rearward.

As long as you hold the trigger back, the bolt will reciprocate, causing the weapon to fire repeatedly until you release the trigger, raising the sear, re-engaging the bolt, stopping its travel.  That's referred to as "fully automatic fire."  It's a single function of the trigger.

With a semi-automatic weapon, when the recoil or expanding gases cause the bolt to travel rearward, the action causes the bolt to trip a mechanism typically called a "disconnector."  This mechanism disengages the trigger from the sear, causing the sear to catch the bolt after every shot fired.

That function of the action is called a "reset."  It resets the trigger for the next shot.

When you use a weapon fitted with a bump stock, you hold it with both hands: a firing hand and a non-firing hand.  You maintain forward pressure with the non-firing hand.  When the weapon discharges, the recoil impulse jogs the weapon rearward, momentarily releasing the rearward pressure from the trigger-finger on the trigger, allowing the action to reset.  The forward pressure from the non-firing hand pushes the trigger back against the trigger finger, causing it to fire again, replicating fully-automatic fire.

But is it fully automatic fire? Not according to the NFA: "by a single function of the trigger."

Bump stocks (and every other full-auto-simulation device currently under scrutiny) utilize the "reset" function of the action.  That makes the cycle a "two-function" operation.  By definition, a "machine gun" is a single-function mechanism.

That's why, when these products originally hit the market, they were accompanied by letters from the ATF declaring them legal.  Those letters prompted tens of thousands of law-abiding citizens to purchase the products.  It was the ATF's own endorsement.  Now the ATF has changed its mind.

Should we accept that hundreds of thousands, if not millions, of law-abiding gun-owners are now suddenly criminals because of the ATF's mood swings?

Mike VanOuse is a Bible-thumper and Factoryjack from Lafayette, Indiana.  More of his work can be found at

Image via Max Pixel.

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