AR-15 rifles have risen significantly in popularity in recent years, and are commonly used in mass shootings.

These military-style guns can inflict serious harm in mere seconds, and the marketing and gun culture around these weapons has evolved in recent years, according to guests on Greater Boston.

Washington Post national security reporter Alex Horton said gunmakers have had success in selling not just the gun itself, but the image around it. He said a person can get an entry level model for just a few hundred dollars.

"You had gun culture that was rooted in being outdoors, hunting, sportsman-type stuff. ... There was a general turn to the next phase of gun culture which was predicated on self defense," Horton said.

Robert Mendoza, a forensic psychologist and owner of Boston Forensic Associates, said shifting the existing gun culture is a challenge.

"If you're going to stop any of this from happening, you're going to have to start way upstream on this thing, and start providing the kind of help that people need as they begin to devolve into these areas where they might explore weapons," Mendoza said.

Watch: How AR-15s have risen in popularity, and made mass shootings deadlier than ever