The tragedy that struck newtown, connecticut, last friday was unthinkable in so many ways, but as we all sadly know, it was not unprecedented. From aurora, to tuscan, to virginia tech, the litanies of... See More
The tragedy that struck newtown, connecticut, last friday was unthinkable in so many ways, but as we all sadly know, it was not unprecedented. From aurora, to tuscan, to virginia tech, the litanies of names, the shooting rampages have become depressingly familiar features of american reality, that one remarkable young man is now fighting to stop. He is on a mission to expose how easy it can be to buy powerful guns in this country. This heartbreaking season continues in newtown. This season of funerals. Three more children laid to rest. As the country struggles to make sense of the horror, there's a voice you should hear. It's the worst day of your life. It's chaotic. It's hopeless. Colin goddard knows what it's like to be in a classroom when an armed madman busts in and starts shooting people. Colin was a student at virginia tech. It was the most terrifying ten and a half minutes of my life. When you're getting shot at, you're just in shock. Colin was hit by four of the bullets. Three of them are still in him. Weeks after the shooting, he recalled those moments. The shooter came inside and we were all on the ground, not moving, not making a scene at all, just lying there acting -- playing dead, you know, almost every one of us. We were just at his mercy. He could have done whatever he wanted to, and he chose to go around the room in such a way that he killed all the other students in my class except for a few of us. Yeah, it's been a little messy. Colin goddard's moment of recovery, the rehab, the psychological therapy, the search for answers and meaning, it's all led him to this. We are better than this. We are better than a nation with mass shootings in movie theaters and schools and on our streets. He works at the brady campaign to prevent gun violence, but he does more than lobby and make public service announcements. He goes undercover to gun shows across the country and he says he proves how ridiculously easy it is to buy guns without any kind of background check at all. As he shows us in a documentary called "living for 32" after the 32 virginia tech students who were murdered. The llama here. The llama? I paid $300 for it. I wouldn't mess with it for less than $20. I'm a retired schoolteacher. 40% of the guns sold in america are purchased at gun shows. More than five million people attend these events every year. They generate billions of dollars in sales, and since only licensed dealers are required by the law to perform background checks on the people they sell guns to, all of the private sellers ere -- you can find them at every show -- sell guns without any check at all. That's the gun show loophole. And colin goddard has made it his mission to close it. Here at a gun show in ohio, he says he and his friends were able to buy an assault rifle without even an i.D. You want $660 for it? Yeah, out the door. Have to be over 18, and an ohio resident. No tax, no paper work. And I need to see your driver's license. I don't have it on me. I BOUGHT TECH NINES, MAC 11s, The same gun that was used to shoot me. I bought it all. All without a background check and it was all legal. My question is why is that legal? Were you shocked? I was. I didn't think I was going to be able to do it at first, and then once I did it once and then did it twice and then three times, i was like wow, this is really easy. And it worked? And it worked every time. Polls show a strong majority of americans favor closing the gun show loophole, but in newtown, that wasn't the problem. At virginia tech, that wasn't the problem. The killers used legally purchased weapons. There's not one thing that's going to stop all shootings. There's not one policy that's going to save us all. But, you know, background check is something that will make it more difficult for dangerous people to get their hands on a gun. Colin goddard is not a victim, but a survivor and a citizen activist with a youthful conviction that yes, we can be better than this. I can't do this alone. I need people to come together on this. That's why I share my story. This is only goingo be a period of my life. It's not going to be forever. But to the extent that I can share my story and move the balfour ward, let's do it. Let's help save some lives.
This transcript has been automatically generated and may not be 100% accurate.