The ever-present fear of a school shooting is something that lingers in the mind of nearly every parent these days when they send their kids off to school.

But what if you could shield your child with something as simple as a backpack?

So-called “bulletproof backpacks” are selling out across the country. They even come in kid-friendly colors like raspberry and pink.

The packs run about $200. They have a Kevlar panel sewn in the back so they can be used as a shield or be thrown over the shoulder if you're running away. Manufacturers say they meet federal ballistics standards, but how well do they really work when under fire?

We decided to ask an authority.

Lynn Westover was a special operations sniper in the Marine Corps. He is a 12-year veteran with tours in Iraq and Afghanistan and is a firearms expert.

We let him put the packs to the test.

The first weapon we used was a Sig Sauer .380 – popular for personal protection. It's the kind of gun a mom might keep in her purse.

Westover fired directly into the pack from 21 feet away. The Kevlar stopped all three shots.

Next, we fired a Sig Sauer 45. It's a semiautomatic, packing more firepower than the .380 and is another popular handgun in American households.

Once again, the backpack performed well, stopping the bullets, but the sheer force of the .45 caliber round could still do some damage.

“If it hit you in the back, you could see some possible spinal trauma,” said Westover.

While handguns account for the majority of school shootings, assault-style rifles have recently become the weapon of choice for mass shooters.

We tested a Smith & Wesson M&P15T, .223 caliber – the same set up used during the mass shootings in Newtown, Las Vegas, Aurora, Colo., San Bernardino, and most recently Parkland, Fla.

The pack took three direct hits from 60 feet away.

Each shot went right through the Kevlar.

“This backpack is not gonna stop that,” said Westover. “It's not gonna stop any rifle.”

It should be pointed out that manufacturers don't claim the backpacks will stop a rifle round – only handguns like the ones we tested.

“I would say it's effective exactly as advertised,” said Westover, who was skeptical of how effective any backpack would be in a real-life situation. “If you're running away, you’re supposed to make sure you have the backpack on your back. If you're sheltered in place you should have the backpack in front of you. Do you really think you're gonna get a 10-year-old kid to be present enough to know to do that, or to even keep the backpack on him when he's running?"

RELATED: Sales of bulletproof backpacks surge after Florida shooting

There are other skeptics as well.

Mary Schoenfeldt is one of the world's leading authorities on what to do when a school shooting comes to your community. She was there in the aftermath of Marysville-Pilchuck High School when a school shooter killed four classmates in 2014. Schoenfeldt lives in Marysville and has grandchildren in school, but isn’t sold on “bulletproof backpacks.”

“I think it's a knee jerk reaction,” she said. “I think it's a very similar reaction to the conversation about arming teachers.”

Schoenfeldt argued the backpacks would do more to soothe parents' fears than to protect their children.

In fact, she worries they could do more harm than good.

“I think they can give a false sense of security,” she said. “Parents can buy it, kids can wear it and feel like, we've got this one. We don't have to do any more in order to create a safer world.”

Schoenfeldt favors a comprehensive approach to combat school shootings including tougher laws, training for teachers to identify troubled kids and training to help students better listen to their teachers during an emergency. She even likes the idea of training teachers in emergency first aid.

“In addition to marching in Washington, D.C., let's add some other actions and let's do some skill building,” she said.

Both Schoenfeldt and Westover worry about the psychological impact the backpacks might have on children, and agree when it comes to school shootings no single solution is bulletproof.

“I wouldn’t buy one for my kid, because I wouldn’t want him to feel like he’s going to school in a war zone,” said Westover. “There are better ways. We need to look at prevention.”

“I just cannot imagine packing my grandson’s backpack for the day and saying here's your sandwich, here are your carrot sticks, and here's your Kevlar,” added Schoenfeldt. “I just can’t go there.”

Editor's note: Lynn Westover, who was interviewed for this story, is married to a KING 5 employee.