"But unlike traditional bump firing, the Slidestock allows the shooter to properly hold the firearm and maintain complete control at all times," the website says.
Each plastic Slide Fire stock — available for AR- and AK-style rifles — comes with a copy of a 2010 letter signed by John R. Spencer, firearms technology chief for the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, deeming it an unregulated firearm part.
In seeking ATF's blessing, according to Spencer's letter, Slide Fire claimed the device was "intended to assist persons whose hands have limited mobility." But gun shop owners have told the AP that most of their sales have been to able-bodied shooters.
Dorothy Royal, manager of Surf City Guns in southeast North Carolina, sells about a dozen Slide Fire stocks a month, mostly for AR-type rifles. Although many of her customers are wounded veterans, she guesses about 70 percent of the buyers have no disability.
"To the best of my knowledge, without taking them outside and putting them through a physical test," she said.
Royal can see how a lay person might have difficulty telling one of these weapons apart from a real machine gun. But she said there are differences.
"If these were designed to work with a belt-fed gun, you would have a totally different character here," she said. "You go through a lot of ammo here. It's not accurate."
She clearly hadn't seen the video posted on Slide Fire's website.
Produced by the magazine Guns&Ammo, the video features Sgt. Jason Teague, a sniper with an Atlanta-area police SWAT unit. The video caption says the marriage of Valkyrie Arms' belt-fed drum magazine and the Slide Fire stock produces an offspring that "bridges the firepower gap between a rifle and a machine gun."
With a combination of short and long bursts, Teague perforates the face and chest of a cleaver-wielding assailant on a target with a fusillade of red- and green-tipped "Zombie Max" bullets.
"This is definitely something that's a game-changer for you guys out there who want to put down a heavy volume of fire," he says. "A lot of firepower — EASILY able to fight off that next big horde that comes after you."
And, Teague assures, "it's completely legal."
Cottle's home page boasts that "Slide Fire's patented technology allows the shooter to accurately and safely fire your rifle as quickly as you desire."
Some full-auto purists agree.
According to his YouTube channel, Jeffrey Zimba has spent more than two decades "in the Military Firearms industry." Over the years, he's tested many devices and gadgets intended to simulate the rush of firing a machine gun, but hadn't found "anything that really gave you something that you would think was close to a full auto.
"Not," he said, "until now."
In a video, Zimba unloads two clips from two different rifles into a pair of paper targets from 15 yards. All but one of the rounds is in the black.
"Proof's in the pudding to me," he says. "As far as I'm concerned, very controllable. Not a waste of ammo."
Shooting instructor Frankie McRae disagrees.
"To get consistent" requires unconventional training, says McRae, co-owner of Range 37, a shooting club in Bunnlevel, not far from the Army's Fort Bragg. "You're not holding the gun correctly. The gun has to move within the stock here, and that takes away from the fundamentals of a good stance and good grip with the rifle."
Bump-fire weapons don't appear to have turned up at crime scenes and aren't generally on the law enforcement radar. McRae says banning the devices wouldn't affect criminals, who would continue to buy restricted weapons illegally from "other criminals."
"I wouldn't want one of these if I was going out to hunt people," McRae says after emptying a couple of magazines from a fully automatic Colt CM901.
- Jason Chaffetz: Mitt Romney is leaving door...
- Scholarship lotteries, popular with everyone,...
- Vikings place Adrian Peterson on exempt list,...
- Wearing this one thing can help boost a...
- Top 15 states for education
- Striking or spanking a child is not a...
- US tobacco growers brace for tougher competition
- School police stock up on free military gear
- Jason Chaffetz: Mitt Romney is leaving... 68
- US wealth gap putting the squeeze on... 26
- Obama 'confident' of Islamic State... 19
- Utah's Gov. Gary Herbert eyes more... 12
- Chicago, NY, Hawaii on Obama library's... 12
- President Obama: Ebola outbreak a... 12
- US won't rule out working with Iran... 6
- School police stock up on free military... 6