Assault weapons are large, ominous-looking guns — or at least that's how we colloquially define them. There is no strict definition of an assault weapon, but they tend to be modified versions of military weapons that can unload dozens of rounds in quick succession. These are the types of guns that President Obama has proposed outlawing, a policy he advocated for after a shooting in San Bernardino, California, that left 14 dead and 21 injured.
"We ... need to make it harder for people to buy powerful assault weapons like the ones that were used in San Bernardino," Obama said in a primetime television address on Sunday.
They are military-style weapons, and there should be serious consideration of whether we should ban them. They contribute to how destructive mass shootings are.
But the debate over which guns to ban is often myopically focused on these military-style weapons, perhaps because they look scary. It ignores the fact that non-assault handguns can also fire dozens of rounds per minute, with trivial reload times, and that some handguns can accept high-capacity magazines. Only eight states have laws on magazine sizes.
Some have argued that assault weapons are the "armament of choice" for mass shootings. But data shows that the large majority of mass shootings don't involve assault weapons. And if we take a step back and look at America's gun problem as whole, the data shows that the guns that kill the most in this country aren't the big, scary-looking ones. They're handguns.
So if we're talking about banning guns or certain features of guns, what we really need to talk about is all guns — regardless of how they look. The distinction between "assault" and "non-assault" weapon is just a rhetorical line that doesn't always consider how dangerous the weapon is.
How the government defines what counts as an "assault" weapon
Guns aren't just one-piece objects; they are a collection of parts. So banning a model of gun isn't particularly useful, as California found out, because gunmakers can come out with similar guns with different names.
When Obama talks about assault weapons, he's likely referring to a vague notion of a big, military-style gun that can fire dozens of rounds quickly. But the specifics aren't clear. That said, there are some features, which you can see in this graphic, that could lead to a gun being categorized as an assault weapon. This is certainly not comprehensive, but what these features have in common is that they make the gun a more powerful weapon, with increasingly lethal power.
What makes these weapons especially dangerous is their ability to fire a large number of bullets in a short timespan — essentially "spraying" their target with bullets, allowing for even those with poor accuracy and precision to cause damage. The bullets are actually smaller in most assault weapons than bullets from your typical handgun, but these weapons can often accept large magazines that can hold a lot of ammunition.
The features Congress targeted when it banned assault weapons in 1994 increased the lethality of these weapons. For example, the grenade launcher and bayonet mount gives the shooter the ability to add more weaponry to the gun. Congress decided that if a gun had two or more of the defined features, as well as a detachable magazine, it would be considered an "assault weapon" and would be outlawed.
But that ban expired in 2004. A proposed 2013 assault weapon ban, with a slightly different definition of "assault weapon," failed to pass.
Now you can own an assault weapon, as long as your state allows it — and most states do.
And the Obama administration has targeted these weapons as it looks for ways to control gun violence in America.
One big misnomer: Semi-automatic assault weapons are not machine guns
One misnomer is that a semi-automatic assault weapon is a machine gun. This is false. Play with the interactive at the top of this story and see the difference for yourself.
The difference is that machine guns, or fully automatic guns, fire multiple bullets when you pull the trigger, whereas a semi-automatic gun fires one. The reason it's called semi-automatic is because after you fire, it automatically loads another bullet into the chamber. This means you can fire many rounds quite fast.
But just because machine guns are banned doesn't mean there aren't a lot of guns that look like machine guns. That's because after the machine gun ban, gun manufacturers altered these military-style weapons so that they only fired one shot when you pulled the trigger, making them semi-automatic instead of fully automatic.
The difference between an "assault weapon" and a handgun might not be as big as you think
Most modern guns are semi-automatic, including most handguns — and that's a big part of what makes them so dangerous, regardless of whether they fall into the assault category.
A German engineer in the late 1800s invented the technology that feeds a new bullet into the chamber after every shot. Without this technology, you had to do something manually before you could shoot again, like pulling back the hammer on a revolver. Uptake was slow, and even in 1980 only 32 percent of handguns produced in the US were semi-automatic.
But by 1994, 77 percent of handguns were semi-automatic.
That matters, a lot. Play with the interactive at the top of this story. You'll notice that there isn't a huge initial difference between a semi-automatic pistol and a semi-automatic assault weapon. Both allow you to fire multiple bullets in rapid succession.
The assault weapon lets you keep shooting and shooting and shooting without a reload. Still, reload times for both weapons are very fast. That's because these guns can be reloaded by feeding an entire magazine of bullets into the gun all at once. With a revolver, you have to slide one bullet at a time into the cylinder. (Some readers have pointed out that a device like a speedloader would speed up reloading a revolver.) That used to make shooting multiple bullets much slower and more difficult.
Small changes turn an "assault" weapon into something else
It's quite easy to turn a military-style gun into something that Congress wouldn't consider an "assault weapon" under its various definitions. This video from the San Diego Union-Tribune gives a great example of how small adjustments in the components move a weapon in and out of this categorization:
For example, if you had a nondetachable magazine that held fewer than 10 bullets, then you could legally have features like a forward pistol grip or a flash suppressor. This is because if the magazine isn't detachable, it takes a lot more than a few seconds to reload the entire magazine.
That said, you can still detach a "nondetachable" magazine quite quickly; it just requires a small tool.
The mass shootings with large body counts used assault weapons. But shootings with handguns also have huge death tolls.
In the mass shootings that have garnered the most attention — including San Bernardino, Sandy Hook, and Aurora — military-style assault weapons were part of the shooters' arsenals.
But Mother Jones's database of mass shootings shows there are plenty of shootings where the shooter just had an array of semi-automatic handguns. The most recent and notable is the 2007 Virginia Tech massacre, when the shooter killed 33 people with two semi-automatic handguns.
In homicides and suicides, the most common weapon of choice is a handgun. In fact, when we look at the percentage of homicides caused by a rifle of any kind — much less a semi-automatic assault rifle — it comes out to about 2 percent, according to FBI data.
Assault weapons do drive up the death toll when someone wants to kill a large number of people. That shouldn't be surprising, because assault weapons were literally designed to kill large numbers of people during combat and allow for huge magazines.
But banning assault weapons won't greatly reduce the number of US gun homicides — and it won't prevent mass shootings. Modern handguns also have the lethal ability to fire multiple bullets in quick succession — and just because they look less ominous doesn't mean we should treat them as any less dangerous.