Following the massacre in Parkland, Florida, Representatives Ted Deutch (D-Fla.) and David Cicilline (D-R.I.) introduced their version of an assault weapons ban.  The bill would ban the sale of "assault weapons" and "high-capacity" magazines manufactured or imported after the law's enactment.  Weapons already in circulation would be "grandfathered" in.

The bill classifies firearms as "assault weapons" based on a feature test; it classifies magazines as "high-capacity" if they can hold more than ten rounds.

Under the bill, a semi-automatic rifle is an assault weapon if it accepts a detachable magazine and has one of the following features: pistol grip; forward grip; folding, telescoping, or detachable stock; grenade- or rocket-launcher; barrel shroud or threaded barrel.

The bill stipulates a similar test for semi-automatic pistols and shotguns.

Contrary to popular belief, this type of guns is legal outside the United States.  Canadians, for example, can purchase a Tavor or similar rifle with a basic firearms license.  New Zealanders can purchase a "featureless" AR-15 with a basic firearms license; they can also purchase one with a pistol grip and flash-suppressor if they are willing to go through the paperwork.

Further, feature tests do not make much sense as policy.  There is no reason to believe that pistol grips, forward grips, telescoping stocks, or barrel shrouds increase the lethality of a firearm.  They may make a gun more ergonomic or tactical-looking, but they do not change how it functions.

The bill includes a list of firearms banned by name and a list of firearms explicitly exempted by name.  The bill specifically exempts the Ruger Mini-14 – despite the fact that it was used to perpetrate one of the world's deadliest mass shootings – and explicitly bans the Beretta CX4 Storm.

Both rifles are semi-automatic and accept detachable magazines.  The Mini-14 fires the same ammunition as the AR-15, the 5.56 rifle round.  The CX4 fires the weaker 9mm luger pistol round.  The relevant difference for the bill's sponsors seems to be that the Mini-14 looks like a traditional rifle with a wooden stock, and the CX4 looks like a prop from a science fiction movie.

Regulating weapons based on how they look doesn't make much sense, which is what the new assault weapons ban does.  Gun control proponents would likely point to the bill's other major component – its ban on high-capacity magazines – to defend its efficacy.

While it's plausible that limiting magazine capacity could reduce the number of victims, there isn't much hard evidence for this.  The alleged perpetrator of the Parkland, Florida massacre used ten-round magazines because they were easier to fit in his bag.  The perpetrator of the Virginia tech massacre used a handgun with ten- and fifteen-round magazines.  For an experienced shooter, the time it takes to change magazines might not make a big difference.

Further, limiting magazine capacity would reduce the ability of the average citizen to defend himself.  When New York State passed a law limiting magazine capacity, it didn't include an exemption for retired and active law enforcement.  Following backlash from police, they amended the law to create an exemption for retired and active-duty officers.  If a retired cop needs a seventeen-round magazine to defend himself, it's hard to argue that the average citizen doesn't.

Mass shootings are horrific, and doing nothing is unacceptable.  However, this new assault weapons ban lacks a rational basis.  There's no reason to believe that threaded barrels or polymer furniture makes guns deadlier.  Ineffective and stupid laws are not the answer to mass shootings.

Image: Teknorat via Flickr.