CHESTERTOWN, Md. — Don’t expect Congress to take a quick vote banning bump stocks, the device that allowed the Las Vegas gunman to shoot his semi-automatic rifles at a rate resembling the rapid fire of a fully automatic weapon.

Speaker Paul D. Ryan said Thursday at a press conference here that he and many other lawmakers are just learning of the existence of bump stocks. Congress first needs to examine how they are even allowed under current law, the Wisconsin Republican said, suggesting that a regulatory fix may be preferred over congressional action.

“Fully automatic weapons have been outlawed for many, many years,” Ryan said. “This seems to be a way of going around that. So obviously we need to look at how we can tighten up the compliance with this law so that fully automatic weapons are banned.”

The National Rifle Association on Thursday issued a statement saying it believes bump stocks should be subject to additional regulations.

“Despite the fact that the Obama administration approved the sale of bump fire stocks on at least two occasions, the National Rifle Association is calling on the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) to immediately review whether these devices comply with federal law.”