The demand for guns has skyrocketed in the Lowcountry and across the nation, with buyers rushing to purchase semiautomatic, military-style rifles such as the AR-15 used Friday in the deadly Newtown, Conn., elementary school massacre.

Sales began spiking after President Barack Obama on Friday called for “meaningful action to prevent more tragedies,” such as the Newtown shootings.

Adam Lanza shot his mother to death at her house, then gunned down 20 children and six adults at the school. He killed himself as police closed in.

Sales tend to increase any time there is a public perception that new laws restricting gun sales might be on the way. But the latest flurry of sales surprised even gun dealers.

The 48-slot rack of semiautomatic rifles at ATP Gunshop and Range in Summerville has “lots of holes” after the rack was emptied and restocked, said owner Arlyn Pendergast.

He normally sells about one of the rifles per day. Now he’s selling 10 a day.

Atlantic Game and Tackle in Mount Pleasant “tripled in sales,” said owner Jeremy Burnham. He sold out of semiautomatic rifles Saturday, saying sales “went through the roof.”

Neither dealer has been able to get resupplied, they said. The distributors have sold out.

“There’s zero available. I have more than 100 on back order,” Burnham said. One of his distributors went from a supply of thousands of the rifles to none in eight hours Saturday.

It’s not just AR-15 rifles that are selling fast; it’s the ammunition and the 30-round magazines associated with them. Burnham was told manufacturers are pressing so hard to keep up with demand for the guns that some companies have retooled their production lines, building fewer pistols and shotguns.

Smith & Wesson firearm manufacturers in Springfield, Mass., would neither confirm nor deny that.

“Our hearts go out to those impacted by this terrible tragedy. We feel that further comment would be inappropriate,” said Liz Sharp of Smith & Wesson.

Burnham said customers who hadn’t thought about buying a military-style rifle tell him they increasingly are concerned about the chipping away of their Second Amendment “right to bear arms,” which they see as enacted to allow citizens to stave off government oppression.

“They’re heartfelt about the (Newtown) situation,” he said. “For the most part, they want to make sure they can get the guns they want to own.”

Pendergast said other rights, including freedoms such as speech and religion, could be in peril if the right to bear arms is further restricted.

“Be careful with the First Amendment,” he said, “or there’s no Second Amendment.”