In the wake of the accidental death of a gun instructor in Arizona, many are likely asking how a 9-year old was allowed to hold and fire an automatic weapon. But gun laws in the United States — specifically those concerning minimum legal age requirements for gun possession — are actually still surprisingly lax.

Federal law prohibits handgun ownership by any person under the age 18, with a handful of exceptions. But there is no minimum age for long gun (i.e. rifle and shotgun) ownership. Twenty states and the District of Columbia have set their own minimum age laws ranging from 14 in Montana to 21 in Illinois, but in the remaining 30 states it’s technically legal for a child to possess a long gun.

That doesn't mean that a child can walk into a gun show and purchase a gun. "There are federal laws for minimum age purchasing of firearms," said Daniel Webster, the director of the Johns Hopkins Center for Gun Policy and Research. "Technically, anybody selling a gun in that context should look for age verification that someone is at least 18 years old."

But a child's parent could. "If dad wants to give his son a rifle or a shotgun on his 13th or 14th birthday, he's pretty much free to do that in most states," Webster said.

It's also perfectly legal in many states for children to fire guns of all types at shooting ranges, like the one where the accidental shooting took place yesterday, so long as an adult or instructor is present.

The gun used at the shooting range incident, an Uzi, is a submachine gun that could be classified as either a handgun or a long gun depending on the model and any modifications to the gun. While federal law would prohibit minors from owning the pistol version of the gun, there are no such federal restrictions on the rifle version. "The laws aren't designed in essence to protect children from accidental shootings of this nature," Webster said. "There's a mindset that's fairly prevalent in the U.S. that there's nothing wrong with kids firing guns."

The industry pitch for the gun has revolved around the efficiency of its operation and thrill of its use. "Shooting the UZI pistol is just pure, economical recreation with a ton of fun thrown in," Richard Turner, the vice president of sales and marketing for Umarex USA, which manufactures the gun, told the magazine Guns & Ammo in 2012.

Tuesday's incident, however, highlights the gun's potential for danger, and the potential danger in gun use more generally. Accidental gun deaths make up a significant portion of overall gun deaths in the United States. The good news is that while gun injury statistics are notoriously spotty (by design), gun fatality data from the CDC shows that accidental gun deaths have been on a steady downward trajectory since at least 1999. There’s a similar, though less pronounced, trend for all accidental gun injuries.

But it’s important to note that these numbers could be too low. A recent study found that federal reports of accidental child gun deaths are significantly underreported. There’s good reason to assume that accidental gun deaths and injuries are underreported for all ages. "You are potentially looking at accidental shootings that are twice current estimates," said Sam Bieler, an Urban Institute researcher who studies gun violence.

Webster believes that there are both cognitive and physical limitations in children that make it more difficult for children to understand and apply rules they are taught from a young age. "A very common view of gun-owning parents is that what gun safety is all about is teaching your children rules," he said. "What they don't consider are the developmental issues and physical abilities of children to actually follow these instructions. It was obvious to me when I saw this nine-year-old girl holding an incredibly powerful gun like an Uzi. Why anyone was surprised when she couldn't handle the recoil is beyond me."

The National Rifle Association didn't immediately respond to a request for comment.