What is a bump stock?
A bump stock is a gun stock that uses the recoil action of a semi-automatic rifle to simulate fully automatic firing. A gun stock is the part of the gun that connects the firing part of a gun to the human who operates it.
The mechanism of the bump stock is quite simple. The bump-firing stock is in two pieces, allowing it to slide back and forth as if on a drawer slide. It is called “bump-fire” because the recoil of the gun sends it backwards, and the shooter causes the gun to go forward, “bumping” the trigger.
How does a bump stock work?
Bump firing can be done on most semi-automatic firearms without the addition of any mechanism. Bump firing is done by releasing the grip of the gun and letting the firearm ride freely. The trigger finger is held stationary. Each time the gun completes the firing cycle, the shooter pushes the gun forward. The trigger contacts the trigger finger, and the cycle continues.
What is the purpose of a bump stock?
Most shooters who try bump-firing or use a bump stock do it for entertainment. It is inherently inaccurate, unlike fully automatic shooting. Many shooters bump-fire so they can legally experience the closest thing to automatic firing.
It should be clearly understood that a bump stock does not change any aspect of the firing mechanism of the gun. Since it really doesn’t change anything, it does not change the classification of the firearm either.
Bump-firing is a novelty, and nothing more. I personally have never gotten the bump-firing thing down. I might get a few rounds off, but it has never worked for me. Since I purchase my own ammunition, I don’t spend any time practicing.
Succinctly, bump-firing devices are for YouTube shooters, not serious sports enthusiasts.
Why are bump stocks legal?
For semi-automatic guns, as long as the firearm requires the shooter to do something to fire every round, it is a semi, not fully automatic, firearm. A bump-firing shooter is actually shooting every round, and therefore not NFA or GCA controlled.
Since a bump stock really isn’t anything more than an instrument that enhances something that a rifle can do naturally, legislation and enforcement isn’t practical. In fact, states like California and New York have ironically improved bump-firing capabilities by enacting more gun restricting laws. That is, the outlawing of pistol grip and thumbhole stocks has caused manufacturers to design gripless stocks that are easier to bump fire.