In today’s Los Angeles Times, Senator Dianne Feinstein lays out her best case for a ban on “high capacity” magazines, and it boils down to a simple premise: if killers use smaller magazines, lives will be saved.

The primary effect of a high-capacity magazine — which is defined as a magazine holding more than 10 rounds — is more dead bodies.

Last week, the House Judiciary Committee advanced a bill that would ban such ammunition magazines — the Keep America Safe Act — along with bills to promote so-called red flag, or extreme risk, laws, which keep guns out of the hands of dangerous people, and a bill that prevents those convicted of hate crimes from purchasing or owning weapons.

The magazine ban passed by the House would ban the manufacture, sale, transfer, and possession of magazines holding more than 10 rounds, though it does contain a grandfather clause allowing individuals to maintain possession of existing magazines. The punishment for violating the law? Up to five years in a federal prison.

While the bill as written does contain a grandfather clause, Feinstein notes that the legislation also contains funding for a “buyback” of magazines.

But it’s not enough to simply stop the sale of new high-capacity magazines. We also need to address the supply already on the street. The Keep Americans Safe Act includes another provision of my assault weapons ban that would allow federal funds to be used to buy back high-capacity magazines, providing an incentive for people to retire such magazines.

Of course, in Feinstein’s home state of California lawmakers decided to simply require gun owners to turn in their magazines. Instead, a federal judge blocked the law from going into effect, and for one magical week, Californians could actually purchase “large capacity magazines” without violating state law for the first time in over 20 years. It’s estimated that as many as 1,000,000 magazines were legally purchased by Californians that week, which demonstrates that Feinstein is simply wrong when she says that the only reason people want these magazines is to take as many human lives as possible.

In fact, Dr. J. Eric Dietz of Purdue University’s Homeland Security Institute has been conducting research into magazine capacity and self-defense, and says his studies show increased magazine capacity saves lives.

“With the way we had the modeling set up, every single [additional] round added to the capacity. So, theoretically, even a hundred round magazine would have continued to add capacity. This is not really new. Anybody who’s got military or law enforcement time knows more guns in a gun fight on the friendly side are good and the outcome is usually better because of that. So I think this reinforces maybe our gut reaction to the magazine bans and the magazine capacity issue overall.”

One other big issue with Feinstein’s demand for a magazine ban is enforceability. The “Keep Americans Safe Act” would require all new magazines to be stamped with a manufacturers date, but there are literally tens of millions of magazines in private hands that don’t have any markings that would allow law enforcement to know when they were made. We’ve also seen how easy it is to print your own magazine with a 3D printer, which means that even if companies were to stop making magazines, the illicit market could quickly and easily adapt.

Not only is Feinstein wrong on the merits of her ban, but the difficulty in enforcing the proposal means that it’s not likely to get much use, beyond being perhaps another charge federal prosecutors could levy against someone already facing gun and/or drug charges. Her magazine ban is a bad idea on multiple levels, but unfortunately we’ve seen that Feinstein’s never met a gun control bill she doesn’t like, no matter how ineffectual, unconstitutional, or unenforceable it might be.