What weapon did the gunman use in the recent shooting at Marjory Stoneman Douglas High School in Florida?
If you said the AR-15, you'd be wrong. And we'll explain in a moment.
For more than a half-century, the AR-15 has been popular among gun owners, widely available in gun stores and, for many years, even appeared in the Sears catalog.
Yet over the past decade, the AR-15 and its offshoots have been used in many of the country's worst mass shootings. This has reignited the debate about their widespread availability.