This one will pretty much be a slam dunk, right? Unlike almost all other gun-control demands in the aftermath of mass shootings, this proposal actually does have something to do with the incident that it addresses:

Sen. Dianne Feinstein, a longtime advocate of stricter gun control measures, introduced a bill Wednesday that would ban the sale and possession of ‘bump-stock’ equipment and other devices that essentially turn a semi-automatic weapon into an automatic one. The Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) told reporters Tuesday that multiple bump-stocks were found in the hotel room used by the shooter, who opened fire during the Route 91 Harvest Music Festival Sunday, killing 58 people and injuring over 500 others. According to a copy of the bill text provided to ABC, it would go into effect 180 days after its passage. “It shall be unlawful for any person to import, sell, manufacture, transfer, or possess, in or affecting interstate or foreign commerce, a trigger crank, a bump-fire device, or any part, combination of parts, component, device, attachment, or accessory that is designed or functions to accelerate the rate of fire of a semi-automatic rifle but not convert the semiautomatic rifle into a machinegun,” the bill states.

Jazz threw himself on this grenade, so to speak, earlier this morning by calling this a common-sense compromise in the wake of the Las Vegas massacre. Feinstein’s bill, at least at this stage, seems narrowly tailored to fit those parameters, and does address one key part of the mass shooting, which was the rapid fire across a wide range. Clark County investigators and the ATF found a dozen bump-stock devices attached to normally legal semi-automatic rifles, which allowed the madman to have de facto machine guns in his hands. The massacre itself is an object lesson as to why we have all but banned machine guns from private ownership, save for an extremely limited exception that is constantly monitored.

Assuming that this legislative text remains as is, the bill would remove that discretion from the ATF. It would have no impact on weapons currently available for sale or possession, and its impact on gun owners will be minimal. Getting malefactors to surrender their current devices will be a challenge, but at least the line can be drawn.

Feinstein’s bill doesn’t expand gun control as much as it acts to close a loophole on an existing ban. It will be tough to make a slippery-slope argument on this effort, and with Republicans on the defensive over gun rights at the moment, bump-fire stocks and Gatling cranks are also not the hill they’ll want to defend. In fact, some Republicans want to know why they’re legal at the moment:

While they’ve shown no interest in more sweeping gun restrictions, Republican senators suggested Tuesday that Congress should investigate modifications that in effect skirt the federal government’s virtual ban on automatic weapons. “I think it’d be a good time to have a hearing,” Sen. Lindsey Graham, R-S.C, told NBC News. “Just find out, ‘How does the technology work?’ and is there a legislative solution.” Sen. Dean Heller, R-Nev., said he wanted to talk to gun makers about finding ways to prevent modifications to weapons. “One of the concerns that I have is the ability to manipulate a semi-automatic rifle and turn it into a fully automatic rifle,” Heller said. “There has to be a way to be able to stop this.”

Voilà. But it’s curious that these devices were allowed in the first place. The ATF had no problem shutting down the Auto Glove a couple of weeks ago, which didn’t even modify the weapon itself. It has a rotating cylinder attached to the trigger finger of the glove, which allows for rapid trigger pulls. In their ruling, the ATF used US v Carter to define a trigger as “anything that … cause[s] the weapon to fire.” In that definition, the ATF ruled that “electrically-driven trigger devices are considered “machineguns” because they are a “combination of parts designed and intended for use in converting a weapon into a machinegun.”

If that’s true of a glove — which is not attached to the weapon — why wouldn’t it be true of a bump-fire stock, which is a modification of the weapon itself? Indeed, Auto Glove’s response was that their product wasn’t installed on the weapon (a distinction the ATF rejected), and bump-fire stocks are a modification.

Don’t expect too much resistance to Feinstein’s bill, as long as it remains this narrowly tailored. I’d be surprised if the NRA pushed back too hard on it, but they may expect Republicans to negotiate a national carry-permit reciprocity bill (which deals with a serious problem for law-abiding gun owners) as a trade-off. That’s … gonna be a stretch.

Update: Republicans are already lining up behind the idea: