An inevitable follow-up to last night’s item about “the Liberator,” the schematics for which have already been downloaded more than 50,000 times in just a day online. The good news for Schumer and other gun-grabbers? The feds already have a way to go after plastic guns. The bad news? The relevant statute is set to expire soon.

I … did not foresee 2014 being dominated by Mike Bloomberg ads about the evils of weapons that look like Fisher-Price toys, but this is the world we have, my friends.

The senator also proposed updating the Undetectable Firearms Act of 1988 — which bans guns that can defeat airport security metal detectors — to include printable gun magazines. Defense Distributed has a federal firearms manufacturers license, which Wilson sought after being questioned by the Bureau of Alcohol, Tobacco and Firearms in 2012. That was shortly after a 3-D printer Wilson had rented was seized by its manufacturer over worries he’d violate the Undetectable Firearms Act. The law, which is set to expire this year, exempts licensed manufacturers to produce plastic guns for use as a models and prototypes.

“There’s no reason for a rifle receiver or a magazine to be, quote unquote, detectable,” Wilson says. “And to make this even worse, they’ll say: well it’s okay for manufacturers to make an undetectable receiver, but it’s just not okay for you to make it. It’s an attempt to regulate some gun parts under the guise of security.”

Actually, Defense Distributed has already figured out a way to make “the Liberator” comply with the Undetectable Firearms Act:

It is a legal firearm provided you include a key component — a heavy slug of steel. The first part of the instructions DD provides addresses that slug:

“Print (ONLY) the frame sideways (the shortest dimension is the Z axis). …

“Once the frame is finished, epoxy a 1.19×1.19×0.99″ block of steel in the 1.2×1.2×1.0” hole in front of the trigger guard. …

“Once the epoxy has tried, the steel is no longer removable, and is an integral part of the frame. Now your gun has ~6 ounces of steel and is thus considered a ‘detectable’ firearm. So now you can print all the other parts.”

With the steel slug embedded in the frame, the gun will ping metal detectors, which means you’re good to go — sort of. That excerpt comes from a piece in The Atlantic chronicling the author’s attempt to download and print a working “Liberator” … in New York City. Among the many logistical barriers are local firearm laws, the scarcity of 3-D printers, the extra expense of making sure the material’s dense enough so that it won’t explode in your hand, and the fact that it’s cheaper and easier to either build a zip gun from materials at the hardware store or simply buy one that’s professionally made from a dealer. The fear here is in the technology’s potential to build reliable, accurate weapons at next to no cost, but that future appears to be a long way off.

The political battle isn’t, though. Watching this, I wonder if the GOP will use the Undetectable Firearms Act as some sort of hedge against voting for other gun regulations. I.e. they’ll vote to renew it — I think — but then cite that vote as proof that they’ve done their duty on “common sense” gun regulations and hope that it placates the people who are after Ayotte and Flake to cave on background checks. But who knows? Maybe Paul, Cruz, and Lee will draw the line on renewing the Act on Second Amendment grounds and this’ll play out the same way the Toomey/Manchin vote did, with the NRA rallying behind them and then other Republicans falling in line. I doubt it after all the Ayotte/Flake angst, but stay tuned.