From The Guardian:

Nationally, though, handguns are used in the majority of gun murders, with rifles listed as the murder weapon in fewer than 4% of murders from 2010 to 2014, according to FBI data.

“While bans on military-style weapons are very popular in the gun safety movement, these guns are popular firearms, they’re not used relatively often to commit crimes, and most of the crimes committed with these weapons could and would be easily committed with handguns or other substitutes,” Winkler says.