Bump Firing Your AR-15 at 900 Rounds Per Minute, Legally.

Apparently this is for hunting zombies. Or just hunting. Because assault rifles, particularly assault rifles that fire hundreds of rounds a second, are good for hunting.

This works by "bump firing," where the shooter doesn't pull the trigger back but pulls the rifle forward. Holding it forward with the recoil from each shot pulling it back turns the semi-automatic effectively into an automatic. It's an old technique, but, as discussed at Slate, the perfectly legal Slide Fire turns an ineffective hip firing method into an effective (aimed) shoulder firing method.