George Gray, 60, who said that he already owned “more arms than arms to bear them,” said that he was in favor of more background checks. “If you own a weapon, you should be stable,” said Mr. Gray, who said he had come from Los Angeles to buy a gun for his daughter. “You should be accountable for your actions. I don’t mind stricter background checks. What we’ve done with the mental health in this country — these people used to get care and were in facilities. And in most of these instances, it’s been people with mental problems.”

Some customers at Greta’s said that they wanted to buy guns before any new gun control measures made it more difficult. Bob Davis, 64, said that he wanted a new pistol. “They want to take guns out of citizens’ hands,” he said. “So as a consequence I ordered a gun. And they’re not going to be able to get me a gun for like six months, because of the backlog. They can’t make guns fast enough.”

The gun industry expected a surge in sales even before the Newtown shooting. Gun sales rose after President Obama was first elected in 2008, and many manufacturers expected an increase in gun sales in the event of his re-election. “We believe the continued economic uncertainty and the outcome of the 2012 presidential election is likely to continue to spur both firearms and ammunition sales,” the Freedom Group, which owns Bushmaster, the company that makes the rifle used in Newtown, wrote in a financial report on the quarter that ended Sept. 30.

The possibility that the federal assault weapons ban — which lasted from 1994 to 2004 — might be reinstated was enough to spur sales of semiautomatic rifles with military-style features.

Dale Raby, who manages one of two Gus’s Guns shops in Green Bay, Wis., said his inventory of guns and ammunition was almost cleaned out, and that most of the interest was in AR-15-style rifles.

“I had almost fistfights over the remaining inventory of that type gun,” he said.

Joel Alioto, 44, an Iraq war veteran who lives in the area, said he recently sold an AR-15 rifle at a gun show for $1,700, more than three times what he had paid for it. “I think the shooting in Connecticut was a terrible thing,” said Mr. Alioto, who is unemployed. “But before the shooting the gun was worth 500 bucks. I don’t think I did anything wrong. I wanted to get my teeth done, get a computer and pay for my first year of Bible college.”