The Republican leader of the Congressional Second Amendment Caucus blasted the National Rifle Association's stance on how the federal government should deal with " bump stocks," and said it's a recipe for the Trump administration to search for new gun restrictions in the law where there are none.

"I think it's a horrible idea, to ask the ATF to contort existing law," Rep. Thomas Massie, R-Ky., told the Washington Examiner on Thursday. "I think it sets a bad precedent."

Massie was reacting to the NRA's decision to ask the Bureau of Alcohol, Tobacco, Firearms, and Explosives to re-examine federal law to see if bump stocks could be regulated more heavily. Support for banning or regulating bump stocks grew during the week, even among Republicans, after police said the Las Vegas shooter may have used the gun accessory to fire more rapidly into a crowd Sunday night, an action that killed 59 people and wounded more than 500 others.

Top Republican leaders in Congress, including Speaker Paul Ryan, R-Wis., said Congress should "look" at regulating bump stocks, which are accessories that use the recoil action of a semi-automatic to help fire more rapidly. Some say bump stocks effectively turn semi-automatic weapons into automatic weapons.

The NRA proposed that the ATF look for ways to regulate bump stocks under current law, an idea that, if followed, would seem to avoid the need for legislation in Congress.

But in an interview with the Washington Examiner, Massie rejected the NRA's proposal outright for several reasons.

First, he noted that the Obama administration itself looked at existing law to see whether these accessories should be banned, and decided against it. Massie said Obama's team most likely pushed as hard as it could to find a way to regulate these items, and failed, and that Trump's team would be unlikely to find a more aggressive rationale.

"We're asking the Trump ATF to be stricter on gun owners than the Obama ATF," he said.

But he also warned that the ATF shouldn't be given the political task of finding a way around the Gun Control Act or the National Firearms Act. Massie said those laws hold that an illegal automatic weapon is one that discharges more than one round with a single pull of the trigger, and that bump stocks — or what he calls "bump fire stocks" — still require one trigger pull for each round discharged.

That means, Massie said, that under the plain reading of the law, bump stocks shouldn't be prohibited, even though they do allow more rapid firing. The ATF decided that in 2010, and the decision shouldn't be revisited, he said.

"I trusted they did the right thing, and I think it demonstrates a complete misunderstanding of how a government is supposed to work," he said of the NRA's idea to reopen the regulations.

"I don't think you can read a ban on bump fire stocks into existing law," he added.

Massie warned that justifying a ban or more restrictions on bump stocks might also lead to other restrictions that aren't in the law, but could be created through regulation. He said it's possible the exercise could result in limits on high-capacity magazines.

More broadly, Massie said it makes no sense for Congress to abdicate its responsibility and allow regulators to decide the issue.

"I think it's bad, it sets a bad precedent," he said. When asked what course of action he prefers in light of the growing support for limits or a ban on bump stocks, Massie said nothing should be done at all until all the facts are known about the Las Vegas shooter's methods.

"We have nothing but TV reports where the facts change every day about how many weapons, what were the weapons," he said. "It's not been reliably documented what weapons he had."

"Until we have facts, it doesn't do much good to debate hypotheticals," he said.

Finally, Massie noted that there are several ways people can make legal, semi-automatic rifles fire more quickly, and that some can even do it with technique alone, without any accessories to make it easier. He said banning one kind of bump stock wouldn't prevent people from using items they can buy in a hardware store in order to boost a gun's rate of fire.

"There are at least a dozen ways to make a semi-automatic firearm more quickly," he said. "There is no way to ban bump fire."

While Massie strongly opposes the NRA's proposal, it's not clear how widespread that opposition will be, even within his caucus.

The group isn't like other caucuses that hold votes and take formal positions on issues. Instead, he said, it serves more as a way to educate lawmakers about gun issues. He said the group is open to any Republican who wants to sit in on its meetings, and said that while he has invited some Democrats in the past, they generally don't show up.

"For political reasons they do not want to be associated," he said.

Still, he said the group would likely convene soon to talk about the issue given its sudden emergence.

"If and when we meet on this, everyone can walk out with their own opinion," he said.