YESTERDAY, THE UNITED States experienced yet another school shooting as a lone gunman entered Robb Elementary School in Uvalde, Texas and shot dead 19 children and two adults.

The 18-year-old gunman was shot dead at the scene by responding police officers. Police said he was armed with a handgun and an assault rifle.

The shooting is the deadliest since 2018, when 14 high school students and three adult staff were killed in Parkland, Florida, and the worst at a primary school since the 2012 Sandy Hook shooting in Connecticut, in which 20 children and six staff were killed.

It has once again raised the question of gun control in the US, with many calling for the type of gun used by the shooter to be banned.

What weapons did the shooter use?

According to police, the gunman was armed with a handgun, an AR-15-style rifle and high-capacity magazines.

He had previously posted a photo online of two rifles that he bought the day after his 18th birthday.

Dubbed “America’s Rifle” by the National Rifle Association (NRA), the AR-15 was designed for fast reloading in combat situations, and it can fire dozens of rounds in seconds. The NRA say the gun is commonly used in the US for hunting.

However, they have been used in numerous school shootings in the US, including the Sandy Hook Elementary School shooting in 2012, where 20-year-old Adam Lanza killed 20 children and six teachers with an AR-15-type rifle legally purchased by his mother.

AR-15 rifles are semi-automatic, meaning the user needs to pull the trigger to fire each shot.

The butt, or stock, of the rifle, has a large internal spring that absorbs the shock of each firing. The recoil, the backward movement a shooter feels when the bullet is discharged, is low, making it easier to shoot.

ar-15-assault-rifle-with-high-capacity-magazine-and-red-dot-optic-of-the-type-that-gun-control-advocates-wish-to-ban Alamy Stock Photo File photo of an AR-15 assault rifle with a high-capacity magazine and a scope. Alamy Stock Photo

According to the National Shooting Sports Foundation, a national trade association for the firearm industry, there are over 20 million AR-15-style rifles legally in circulation in the US, a small percentage of the estimated 400 million guns in the country.

How much damage are AR-15 rifles capable of causing?

Families in Uvalde told CNN they had been asked to give DNA swabs to confirm their relationship with their children before having to wait and see if they had been killed.

High-velocity bullets from AR-15 rifles and those similar to them travel at almost three times the speed than those fired from a typical handgun, causing much more extensive wounds as a result.

Trauma surgeons speaking to The New York Times in 2018 after the Parkland school shooting explained how the high-velocity bullet creates a blast wave around the bullet.

The yaw, or rotation of the nose of the bullet away from its line of flight, can contribute to a larger exit wound. The higher the speed, the larger a wound it will create.

Dr Heather Sher, a radiologist who treated victims of the Parkland shooting in Florida, wrote an op-ed in The Atlantic a week after the shooting in 2018.

In the piece, she wrote in graphic detail the impact of AR-15 bullets, explaining that they don’t simply damage, but “decimate” human organs, leaving exit wounds which can be “the size of an orange”.

She described how one surgeon “opened a young victim in the operating room, and found only shreds of the organ that had been hit” by a bullet from an AR-15.

She also explained how the injury along the path of the bullet from an AR-15 is “vastly different” from a low-velocity handgun injury.

“The bullet from an AR-15 passes through the body like a cigarette boat traveling at maximum speed through a tiny canal,” she said.

What are the laws around rifles like this in Texas?

AR-15 rifles were banned by then US President Bill Clinton in 1994 under the Public Safety and Recreational Firearms Use Protection Act, or the Federal Assault Weapons Ban.

The law was in place until 2004 when it lapsed. A study conducted in the same year for the Justice Department found that the ban’s impact on gun violence was mixed, at best, because of exemptions written in the law.

Today, semi-automatic, military-style weapons that were banned under federal law are now legal unless banned by state or local law.

The Texas State Law Library states that anyone aged 18 or over with a valid state-issued ID can legally purchase rifles, shotguns, and ammunition, while you must be aged 21 or over to purchase a handgun.

There is no waiting period for purchasing any type of gun in Texas, and the state does not maintain a registry of guns.

According to the Giffords Law Center, Texas has no law requiring firearms dealers to initiate background checks prior to transferring a firearm.

Surveys conducted by Pew Research Center last year found that nearly half of US adults (49%) say there would be fewer mass shootings if it was harder for people to obtain guns legally, while about as many either say this would make no difference (42%) or that it would lead to more mass shootings (9%).

In impassioned remarks on the US senate floor yesterday, Senator Chris Murphy, who represented Newton, Connecticut, in the House of Representatives at the time of the Sandy Hook massacre, begged his colleagues to pass legislation that addresses the nation’s continuing gun violence crisis.

“This isn’t inevitable. These kids weren’t unlucky. This only happens in this country and nowhere else,” he said. “It is a choice. It is our choice to let it continue.”

“I’m here on this floor to beg – to literally get down on my hands and knees – and beg my colleagues. Find a path forward here. Work with us to find a way to pass laws that make this less likely.”