Machine guns are illegal in the U.S. for most people, but one small company has found a way around that.

Slide Fire, based in Moran, Texas, plans to sell a semiautomatic rifle that mimics the rapid fire of a machine gun and is also fed bullets from a belt, which provides a huge capacity for ammunition -- potentially thousands of rounds.

Brandon Renner, sales and marketing manager for Slide Fire, says the belt-fed rifle, called the SFS BFR, will be available this fall and sell for $6,000.

"It sprays like a fire hose," said Renner. "We recommend no more than 30 rounds on the belt, but one person could make it as big as they want."

Can that be legal?

The Bureau of Alcohol, Tobacco, Firearms and Explosives says yes, since it's still technically a semiautomatic.

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The key is that of the pieces that make up a gun, the ATF regulates only the "receiver." It's the only piece that has a serial number and the only one that requires a background check to purchase. Slide Fire modifies the trigger and the stock -- the butt of the gun that sits against the shooter's shoulder.

Slide Fire's technology uses the recoil of the rifle shot to "bump" the gun, speeding up the rate of fire without changing the gun's classification as a semiautomatic, which requires that only one round is fired each time the trigger is pulled.

In a 2010 letter posted on Slide Fire's website, the ATF wrote: "We find that the 'bump-stock' is a firearm part and is not regulated as firearm under the Gun Control Act or the National Firearms act."

"I can confirm that ATF did approve the device referenced in the letter and that the Slide Fire is legal," said ATF spokesman Christopher Amon.

Slide Fire already sells bump-stocks for $370 that speed up the rate of fire for semiautomatics. The company also sells semiautomatic rifles that have already been accessorized for bump-fire, costing between $1,150 to $1,950. But these guns use magazines, not belts, and thus have limited ammo capacity.

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A spokeswoman for Wal-Mart (WMT), one of the largest gun sellers in America, said the company does not sell Slide Fire products, and will not be offering the belt-fed rifle.

Another major dealer, Cabela's (CAB), did not return messages from CNNMoney about Slide Fire. But the company's website listed Slide Fire products for sale.

James Hill, owner of the Abilene Indoor Gun Range, located about 50 miles away from Slide Fire's headquarters, said he sells the company's bump-fire accessories and they're quite popular with his customers.

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But Hill, who referred to the Slide Fire products as "a poor man's machine gun," doesn't plan to sell the belt-fed gun, because he doesn't believe there will be much of a demand for it.

He said the Slide Fire rifle is a bit more challenging to fire than a fully automatic weapon, but the "learning curve" can be corrected with a bit of practice.

"It's not as easy [as full auto], but it's fairly idiot proof," he said.