Here's how the AR-15 became the weapon of choice for America's mass shooters - and why it's so deadly

Associated Press/Charles Krupa

Craftsman Veetek Witkowski holds a newly assembled AR-15 rifle at the Stag Arms company in New Britain, Conn, Wednesday, April 10, 2013.

Parkland, Florida.

Las Vegas, Nevada.

Sutherland Springs, Texas.

Recent deadly mass shootings in these US cities have at least one thing in common: the AR-15.

This weapon has become increasingly popular in the US, especially since the 1994 federal weapons ban expired in 2004, and has been used in many other mass shootings around the country. Not just the three listed above.

To understand how and why this has happened, we put together a historical overview of the weapon and spoke with David Chipman, a senior policy analyst at Giffords and former special agent with the Bureau of Alcohol, Tobacco, Firearms, and Explosives.

The National Rifle Association did not immediately respond to our request for comment.