Image copyright AP

In the US, being blind is no bar to owning and carrying firearms. The blind people who do it say they are simply exercising their constitutional right, and present no danger to the public.

When Carey McWilliams went to the sheriff's office in Fargo, North Dakota, to fill out the paperwork for a permit to carry a concealed weapon, the staff immediately noticed he was holding the harness to a guide dog.

The woman behind the desk pointed out that he would have to pass a shooting test before being granted the licence, but McWilliams said he knew that. He told her not to worry.

"So then she took a picture of me, and my application then went up through the ranks - it got the signature of the chief of police of Fargo, the sheriff and the state attorney general's office - and they kept calling me and calling me, saying: 'There's a shooting test, there's a shooting test.'"

The day of the test came, and McWilliams duly went along to the police firing range with a friend who was also trying for a permit. The targets were half-size cut-outs of assailants, positioned seven yards (6.4m) away. McWilliams fired a series of shots with a .357 magnum, all of which landed in the heart region of his target.

Find out more Image copyright Carey McWilliams Carey McWilliams spoke to Outlook on the BBC World Service

He also appeared on the disability podcast Ouch Listen to Outlook Get the Outlook podcast Get the Ouch podcast

Clearly, he knew what he was doing.

He had been into guns since he was 15, when, as an air force cadet, he went on a military camp. The marine in charge of the shooting range had a brother who had lost his sight but they still went hunting together, so he let McWilliams handle the M16 machine gun. McWilliams, who before he lost his sight at the age of 10 had dreamed of joining the armed services, was instantly hooked.

Three years later, he asked to enrol on a pistol marksmanship course run by the Reserve Officer's Training Corps, the body that trains officers for the US armed forces. At that time there was no requirement to be enlisted in the army to take the course, and after much discussion, the instructor agreed to take him on. On the range, McWilliams learned to take aim by listening to the sound of his target being wheeled back against the wall. It served him very well. McWilliams says he shot better than two-thirds of his class, and in his final exam scored 105 out of 100, with one bullet somehow ricocheting and passing through the target twice.

He used the same technique in October 2000, in the police firing range in Fargo.

"The deputy sheriff said: 'Well, you have all these stickers here telling me that you're blind, but you passed the test, so you got your permit. Expect a lot of grief because you're a test case for the whole system, no-one's done this before.'"

Concealed carry permits - the licences required to carry a gun in public - are issued at state level, and the criteria and rules vary across the US. While there is nothing in North Dakota's statutes to prevent a blind person - or a person with any physical disability - carrying a gun, in Florida, for example, a "physical inability to handle a firearm safely" is listed as a reason for ineligibility. Yet even there, a blind person with a North Dakota licence would still be able to carry his or her gun, since Florida recognises permits from that state.

Image copyright Carey McWilliams Image caption McWilliams says he used to be against hunting, but became an ardent fan

It's even more straightforward for blind people to own guns if they are content to leave them at home. In most states, you don't need to perform a shooting test or get a licence to buy a gun. Consequently, no-one knows how many blind Americans own guns for home defence, target practice or hunting.

Carey McWilliams started hunting in 2008. When ducks fly across the sky, he says, they make a sound like bicycle tyres on a pavement, and he traces them with the barrels of his rifle. For other types of hunting, such as stalking elk, he goes out with a companion, who whispers directions - up a bit, left a bit, right a bit - but who is not permitted to touch his weapon.

Hunting in this way is not unskilled, says McWilliams. Ever the military enthusiast, he argues that it is no different from how sniper teams work in a warzone, with a spotter giving verbal directions to a marksman. At the moment he presses the trigger, the adrenaline rush is huge. "You could probably lift up a car at that point. After you're done it's like popping a balloon and you just get tired."

Image copyright Carey McWilliams

The bigger the game, the bigger the rush.

"In the beginning I thought it was a joke, that somebody was blind and wanted to go on alligator hunt," says Mark Clemens, who runs a company specialising in shore hunts in Florida. "Then I sent an email back and I guessed he was serious. And once I got him on the phone, you know, he said that he was having a hard time finding anybody that would take him. That's what the sad part was. Everybody thought he wasn't capable of doing it. He was definitely capable of doing it, if he had instructions."

The alligator that Carey McWilliams pulled in with Clemens and his team in 2009 was more than 11ft (3.4m) long. As McWilliams recounts how he killed the beast with a .44 Magnum bangstick - a cross between a gun and a spear - his voice fills with emotion. He paints a picture of lightning, lassos, trucks nearly falling off dykes and a second alligator creeping up on the group from the shore. "They don't die like they do on TV," he says darkly.

Image copyright Carey McWilliams Image caption Clemens says it was obvious how much the alligator hunt meant to McWilliams

Since then, McWilliams has killed a black bear and is now set on African game. He owns "eight or nine" guns, including an AR-15 machine gun, the civilian version of the M16 he handled as a teenager. Meanwhile, he has continued advise other blind Americans about how they can go about getting their concealed carry permit - he says he has now mentored nearly 100.

One of those is Jim Miekka, who in social terms comes from a different world. Carey McWilliams is unemployed, and lives in a trailer home with his wife, Victoria, who describes him as "a redneck - but a harmless redneck - if Carey could drive he would have a big pickup truck". Jim Miekka, meanwhile, is a financial trader who divides his time between Florida and Maine, where he lives on an 80-acre property. But both men have an indefatigable attitude, take pride in being free-thinkers and are completely hooked on guns.

In his 20s, Miekka lost his sight - and two of his fingers - in an explosion in his kitchen, while he was trying to develop a chemical that could be used in mining. Not long afterwards, he began to apply his ingenuity to his new situation. With help from his father, a chemical engineer with about 20 patents to his name, Miekka bought a cadmium sulphide photocell and wired it to turn visual information into clicks like those on a Geiger counter. The clicks intensified when the device was pointed at the outlines of objects, allowing Miekka to make out the edges of buildings and roads.

Image copyright Bangor Daily News Image caption Jim Miekka with the sonic scope of his own design

"I found out that it worked best with a telescope," Miekka recalls, "and at about the same time my best friend Bill was getting into target shooting, and he said, 'Why don't we try mounting it on a gun and seeing how it works?'"

The system is similar to that used for blind shooting in the Paralympics, where a high-frequency tone tells competitors how far they are aiming away from the centre of a target, which is coloured more brightly than the outer rings.

Image copyright Dick Miekka

Over the years Miekka, now 54, has refined his technology, moving over to a pair of stereoscopic photodiodes. His latest scope, made together with a gunsmith, allows him to pick out an orange target of 0.17in (4mm) diameter at 100 yards (91 metres) - something he says four friends with 20-20 vision could not do. It can also pick out standard National Rifle Association (NRA) targets, allowing him to compete against sighted shooters.

"I like going out to the range and out-shooting people that can see," says Miekka. His father, Dick Miekka, has never beaten him, and says he's remarkable to watch. "He finds the centre of his target. And then nothing happens. Nothing moves and the bullet comes out. He is absolutely, totally still. You'd never know that he'd fired the gun except that you heard it and saw the result on the target."

Throughout his life, Jim Miekka has brought this extraordinary single-mindedness to bear on a series of intellectual puzzles. He is the creator of two mathematical algorithms for predicting downturns on the stock market - the Miekka Formula and the Hindenberg Omen - that have long been used by Wall Street traders. More recently, he has become obsessed with a 22-year-old murder case after watching a TV documentary, convinced that the scenario presented to the jury was against the laws of physics and the accused was wrongly imprisoned.

But when asked what achievement he is most proud of Miekka says he likes the fact that if you put the words "world's best target shooter" into Google, the first result you are likely to get is a video of him on his range. Miekka's love of guns doesn't end with target shooting, either. He also enjoys dressing up as a cowboy and competing in fast-draw competitions under the nickname the Midnight Gunslinger. He can draw and fire his six-shooter in half a second.

Image copyright Bay news 9 Image caption Jim Miekka frequently competes with the Classical Fast Draw Society, who use blank ammunition

In 2007, Miekka came across an enticing-sounding book in the tape library catalogue, Guide Dogs and Guns. "My shooting ability is well-documented and undeniable," read the blurb on the back cover." So prepare to step into a world filled with Braille, machine guns, canes, killer whales, guide dogs and nuclear weapons. This isn't a soft, blind man conquers all type of fluff biography but it is a hard-hitting, bare-knuckles, although at times humorous, look into the life of America's first sightless gunslinger."

It was Carey McWilliams' autobiography. Miekka phoned McWilliams and listened to his advice on how to obtain a concealed carry permit. "I learned from Carey that you want to be somewhat discreet," he says. "I knew the key thing was getting a friendly instructor."

Image copyright Carey McWilliams Image caption McWilliams's book, which came out in 2007

This advice was based on McWilliams' failure to get a permit for Minnesota, the state just to the east of Fargo. Even though he passed the shooting test, McWilliams is convinced the NRA instructor in charge tipped off the sheriff that he was blind. "Now why he did that I don't know because if had been of a different race or ethnicity or sex or whatever there would be riots in the street over that, because that's a civil rights issue," he says.

The sheriff, Bill Bergquist, referred the matter to a judge, McWilliams defended himself in court and lost. "He was blind, and that was why we took it to the court," Bergquist says simply, adding that it was his own office staff that told him about McWilliams' disability, not the NRA instructor.

Jim Miekka took his shooting test at a gun show in Florida, under an instructor who, he felt sure, would say nothing about his blindness, and sure enough he received his permit despite Florida's rule that bars those with a "physical inability" from carrying guns. It seems likely that he slipped under the radar.

Miekka says he needs the permit so that he can take his weapons to the range and to quick-draw events. But he also takes the pistol with him when he goes on his daily walks through the countryside, because he is afraid of being attacked by a dog. "There's a 99% possibility that if you have to use it in self-defence it'll be against a dog," he says.

Carey McWilliams is also concerned about dogs, and has good reason to be. In 2009 he was attacked by three German shepherds and had to spend days in hospital receiving treatment. For weeks afterwards he was scared to leave home and is still on morphine today. He says the incident is the reason he can no longer work.

Image copyright Carey McWilliams The whole key to not being shot is basically to leave your hands off the blind person Carey McWilliams

He wasn't carrying his pistol at the time and doubts it would have helped him, since he was too busy covering his neck and face to reach for a gun. But it's not just dogs that worry him.

"Being blind you're naturally more vulnerable to the criminal element," he says. "You're naturally more a pedestrian. You can't avoid a dangerous situation or run from one if an attack occurs. So you're going to have to stand and fight with whatever means you have available. For me, that's a 9mm pistol."

As a backup, he sometimes carries a 10in (25cm) marine fighting knife in his jacket pocket.

"I've only had to extract the gun three or four times in self-defence. One time a person charged me across the yard, another time a person tried to run me down with a car when I was on the street trying to walk someplace. When I pulled the gun, they saw the action, took off and that was it. He was about split second from getting a bullet in the radiator."

At the same time, McWilliams says again and again that he would only use his weapon on someone at point blank range - "I consider my gun a blade with a bang." That is the only way, he says, that he can be sure he is under real attack and - his acoustic shooting skills notwithstanding - pick out his assailant.

To minimise danger to passers-by, he says his gun is loaded with frangible ammunition, which would be of no danger after exiting an assailant's body. "Surgeons absolutely hate those type of shots that I use because they do a lot of a damage internally," he says. "It would make a bullet wound about the size of a dime and an exit wound about the size of a baseball, and wouldn't go very far beyond that."

What is the NRA's take on the issue?

Image copyright NRA

A video published last week on the National Rifle Association's YouTube channel called for blind people to be allowed concealed carry permits - but it was later removed

Commentator Dom Raso condemned an Iowan sheriff for saying he would refuse to issue a permit to a blind person, saying: "It's been proven that people who lack vision have an increased awareness of their hearing and spatial surroundings"

The NRA has not replied to requests from the BBC to clarify its position on blind gun-ownership

Not everyone thinks it makes sense for blind people to carry guns. Stevie Wonder has commented that it is "crazy" how easy it would be for him, blind since birth, to buy a gun. But when asked about these concerns, McWilliams responds that it's sighted people that seem to be doing all the shooting. So long as blind people just use their weapons in defence, at point-blank range, he says the rights and wrongs of them carrying guns come down to good judgment rather than marksmanship.

But how confident is he that, in that moment of fear and adrenaline, he would make the right judgement? McWilliams, who is not a small man, admits that years ago, someone grabbed his arm in the street to try and help him, only to find himself judo-tossed to the ground.

"I've had sighted people get a little aggressive, come up and grab me," he says. "The whole key to not being shot is basically to leave your hands off the blind person."

One blind man who has thought long and hard about when he would shoot in self-defence is Louis Hartley, a former deputy sheriff who lost his sight five years ago.

"It would have to be a lot more than somebody just taking me by the arm. It would be one of those instantaneous type of decisions that you would have to make by what they had said, like 'I'm going to cut your throat,' or 'I'm going to kill you' or 'I have a weapon and I want your money,'" he says.

Image copyright Shane Hartley Image caption Louis Hartley with his pistol

"Or if they knock you to the ground or whatever - you have to make your mind up at that point in time."

His decision to carry a weapon was influenced by an incident in the 1970s, when he saw a fellow officer getting shot. "I decided at that point in time that I would always have a gun on me," Hartley says. Then, after he lost his sight, his sense of vulnerability increased enormously and he finds carrying a weapon "gives you a little bit more sense of a security, knowing you have something to fall back on".

Now 70, he had no difficulty renewing his concealed carry permit in his home state of Oregon. He just had to fill out a form with his son's help and have his photograph taken.

Carey McWilliams acknowledges that his desire for armed protection also comes partly from his personal history. He says he was the victim of physical abuse as a child, and was regularly beaten up at school, both before and after losing his sight. In one incident his collarbone was broken, which led him to study martial arts. Before long, he used his new skills to break a bully's nose with a palm strike. "I learned that basically the best defence is a good offence," he says.

Although he doesn't think guns are for everyone, he believes they do help some blind people become more confident and independent.

"I've always wanted to educate people that the blind aren't just zombies walking around, meant to be taken care of," he says. "Blind people can be empowered to take care of themselves."

Carey McWilliams spoke to Outlook on the BBC World Service. Listen to the programme on iPlayer or get the Outlook podcast. McWilliams also spoke to the Ouch disability podcast.

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