Daily Beast correspondent Megan McArdle attacked the concept of an assault weapons ban by falsely suggesting that there are no functional differences between such weapons and other firearms.

In her November 21 article, McArdle wrote that the differences between assault weapons and other firearms are “largely cosmetic rather than functional,” a claim also pushed by the National Rifle Association. In fact, assault weapons, like the military weapons on which they are based, have functional differences from other guns that increase their lethality.

McArdle's assessment was based on an image that purports to show two nearly identical weapons with only one being regulated under an assault weapons ban.

The image was created by a blogger who used it to argue in favor of the ban, writing that “If you can buy the gun on the top, but can't buy the bottom gun, who cares? You still have a gun.” McArdle responded that “if it makes no difference, than why have the law?” and argued that "'assault weapon' is a largely cosmetic rather than functional description."

In fact, the lower pictured weapon, a Mossberg 500 Tactical Persuader, has a number of features that increase its lethality compared to the top pictured shotgun. Contrary to what the graphic suggests, the only difference between the two weapons is not just the pistol grip featured on the Tactical Persuader. The Tactical Persuader also has an adjustable stock that can be removed from the firearm completely, which allows the gun length to be shortened for increased concealability. Furthermore, when combined with a pistol grip, the firearm can be more easily maneuvered, allowing the shooter to fire from the hip and more easily use the weapon from vehicles and in other close quarters situations.

An almost identical configuration was sought out by Suleman Talovic, a teenager who used a Mossberg-derivative pistol grip shotgun during a rampage that killed five and wounded four at the Trolley Square Mall in Salt Lake City, Utah on February 12, 2007. A recent report issued by the John Hopkins Center for Gun Policy and Research found that firearms with assault weapon features are disproportionally used in mass shootings and that when used result in higher numbers of casualties.

The claim that assault weapons only have cosmetic differences from other firearms is trumpeted by the National Rifle Association, an opponent of assault weapons bans, but has little basis in reality. Unsurprisingly, features that make a firearm an assault weapon are deliberately designed. According to a Violence Policy Center report:

All assault weapons--military and civilian alike--incorporate specific features that were designed for laying down a high volume of fire over a wide killing zone. This is sometimes known as “hosing down” an area. Civilian assault weapons feature the specific military design features that make spray-firing easy and distinguish assault weapons from traditional sporting firearms.