Gun sellers have often said President Obama has been their best friend. Each time the president talks up the need for any sort of restrictions on firearms sales, the only thing that's sure to happen -- because legislation limiting sales never does -- is that gun sales enjoy another spurt.

Indeed, in 2008 the FBI processed 12.7 million firearms applications through its National Instant Criminal Background Check, a figure that leaped to 23.1 million in 2015, providing a rough approximation for sales.

And now some gun dealers say worries about a Hillary Clinton victory in the 2016 presidential election are already helping to keep gun sales booming. "She's going to try to continue where President Obama left off, and that would include the gun control route," said Michael Cargill, owner of Central Texas Guns in Austin, Texas.

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Added Justin Anderson, director of marketing at Hyatt Guns in Charlotte, North Carolina, the nation's largest gun store: "She will be very, very likely do her level best to erode gun rights. There is no question in our minds. There is no question in our customers' minds."

During Sunday's Democratic debate, Clinton, and rival Sen. Bernie Sanders traded barbs over the Protection of Lawful Commerce in Arms Act, which provides immunity for gunmakers and dealers from civil suits stemming from crimes committed with their products. The former Secretary of State and opponents of the law argue that it gave the firearms industry unprecedented legal protections, a notion that Sanders and gunmakers reject.

Clinton also supports what she calls a "commonsense approach" to reduce gun violence, including increasing the number of gun sales subject to background checks. Officials from the Clinton Campaign didn't respond to requests for comment for this story.

"Our industry is certainly going to oppose this type of political rhetoric wherever we can," said Michael Bazinet, a spokesman for the National Shooting Sports Federation (NSSF), a trade group representing the firearms industry.

Smith & Wesson (SWHC), whose roots date to before the Civil War, raised production on some products such as the M&P Shield handgun and the M&P 15 Sport II semi-automatic rifle in the latest quarter. Strum, Ruger (RGR) reported brisk demand for weapons used for self-defense such as centerfire pistols.

Shares of Smith & Wesson have skyrocketed nearly 80 percent over the past year, while Strum, Ruger rose 30 percent, outperforming the broader market. Not surprisingly, both publicly traded gunmakers recently reported better-than-expected quarterly results.

Smith & Wesson earned $551.9 million in revenue in 2015, nearly 90 percent higher than the $293.9 million in 2008. The sales increase at Strum, Ruger was even more dramatic, surging more than 200 percent to $551 million last year from $181.5 million seven years earlier.

The firearms boom is continuing. Requests for permits to the FBI hit 1.48 million in February, a 16.2 percent increase over the year-earlier period, according to data from the NSSF, which the trade group adjusts to reflect sales more accurately. Dealers report doing a brisk business in handguns that users like to conceal and say training classes are often full.

"Any 9-millimeter gun is hard for us to find right now," said Cargill of Central Texas Guns.

Business is also good at Hyatt Guns even though North Carolina has instituted stricter background checks that result in waits of about four months for permits that used to take weeks to process.

"It takes longer to get a gun in this state than in California," said Anderson of Hyatt Guns, who estimates that sales are up about 15 percent this year. "It's pretty frustrating." On the other hand, if Clinton is elected, that will likely mean four more good years for gun sales.