There's just one place in all of Mexico where you can legally buy a gun. It's tucked away in an anonymous building on an army base in the capital, staffed by soldiers.

Those who enter must surrender any cellphones, tablets or cameras, remove caps and pass through a metal detector. Weapons are kept in locked glass cases, unlike many of the 50,000-plus U.S. gun shops where used-gun racks on showroom floors allow easy access and clerks are happy to let you heft an unloaded firearm.

Mexico's constitution guarantees citizens' right to own a handgun and hunting rifles for self-defense and sport. Legally getting your hands on one, however, requires clearing a series of bureaucratic hurdles far stricter than in the United States and, for many, travelling great distances to reach the country's lone gun store.

In fact, most of Mexico's 120 million inhabitants probably don't even know about the Directorate of Arms and Munitions Sales — it is prohibited from advertising any of its goods, or the mere fact that it exists.

But that hasn't stopped sales from booming, in parallel with a large and active black-market trade for contraband weapons flooding south from the United States.

According to army records, the store sold 549 guns in 2000. For 2015, sales had risen to 10,115, an increase reflecting the rise in concern about personal safety during a surge in violent deaths in Mexico.

Sales spiked most dramatically after 2006, when then-President Felipe Calderon took office and declared war on Mexico's drug cartels. The country recorded more than 164,000 killings between 2007 and 2014, according to official statistics.

At the gun store, 27 brands are on offer, from the United States' Colt, Austria's Glock and Italy's Beretta to the locally made Mendoza and Trejo.

Although gun ownership is enshrined in the constitution, the provision also empowers the government to regulate the types of weapons that are permitted and under what conditions. Mexicans can legally purchase one handgun for home protection, while members of hunting or shooting clubs can acquire up to nine rifles of no more than .30 caliber and shotguns up to 12 gauge, said the store's manager, Col. Eduardo Tellez Moreno.

But unlike those who run U.S. gun shops, Tellez would rather no one buy what he's selling.

"It's preferred not to have a gun, even at home, because there could be accidents or worse, accidents within families due to the mishandling of weapons. It's like having a match close to a fire," Tellez said. "It's an obligation of the state to provide security to the people who live in the country, not for you to take justice into your own hands."

Some people aren't confident about authorities' ability to provide security.

On a recent day, Mexico City resident Alejandro Lozano came to pick up a hunting rifle after waiting about a week while his documents were processed. He said he keeps a handgun at home, but wishes he could legally carry it to protect himself from violent robberies targeting bus passengers, motorists at stoplights and customers emerging from banks and ATMs.

"It's not difficult" to get a gun, Lozano said. But "we would like it better that they would let us carry like in the United States . that they let us carry whatever caliber we choose."

At least six separate documents are required to buy a gun: a birth certificate, a letter confirming employment, proof of a clean criminal record from the attorney general's office in the applicant's home state, a utility bill with current address, a copy of a government-issued ID and a federal social security number.

Gun owners must register every weapon they have, and people say it's nearly impossible to secure a concealed carry permit, something that's allowed in the majority of U.S. states.

Luciano Segurajauregui Alvarez, a gun advocate who shoots recreationally and competitively, said those permits are routinely denied.

"If I put my papers in ... they're going to take about three to four, even six months, and then send me a letter telling me that it's the obligation of the state to provide security for all people in Mexico, so your permit is denied," said Segurajauregui, who is a professor of design at Mexico's Metropolitan Autonomous University.

He called that idiotic. "You can't assign a soldier to preserve the security of each and every one of the people," he said.

Gun advocates say relaxing gun restrictions would help private citizens protect themselves from heavily armed gangs that terrorize and extort people in various parts of the country.

Many Mexicans perceive government security forces as unable to do that job, and often actually being in cahoots with the cartels. Since 2013, civilian "self-defense" militias have sprung up in some rural areas as communities became fed up by corruption, organized crime and a failure by police and military forces to keep them safe from drug gangs.

"To see us alone, to see us unprotected by the government, what did we have to do as citizens? Take up arms to defend our families and our own lives," said Hipolito Mora, a co-founder of a militia in Michoacan, one of the country's most restive states.

Yet, while Mexico has a homicide rate more than five times higher than in the U.S., such sentiments have brought no widespread debate about gun rights and there is no political push to ease firearm restrictions.

"I think it's a non-issue," said Alejandro Hope, a security analyst in Mexico City. "The extreme liberal regime around gun control that exists in the United States is seen as a bizarre phenomenon. That carrying guns is seen as a major human right is bizarre."

Mexico's lone gun store sold 52,147 firearms in 2009-14, a figure dwarfed by the black market trade that's largely fueled by illegal American imports. Mexican law bars guns from entering without an "extraordinary import authorization," but enforcement is spotty — 73,684 of the 104,850 guns confiscated in Mexico during the same period were traced to the United States, according to the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives.

There are no current statistics on the number of weapons held by Mexicans. The Geneva-based Small Arms Survey says Mexicans owned 15.5 million firearms in 2007, of which 4.5 million were properly registered with the army.

On the black market, buyers get access to the same kind of high-caliber weapons used by cartels and can avoid paperwork, waiting periods and travel.

For residents in the northwestern city of Tijuana, for example, it's much simpler to buy a gun that has been purchased in one of San Diego's 15 or so gun shops and smuggled into Mexico instead of going 1,700 miles to Mexico City.

Segurajauregui said gun advocates want the military to open stores in each of Mexico's 31 states in addition to the capital, but there is no sign that's in the works.

"Gun reform in Mexico has always been a hot potato," he said. "Nobody wants to touch it. Nobody."