The site Ammoland.com writes that “in a video released by DARPA Thursday, Extreme Accuracy Tasked Ordinance (EXACTO) .50-caliber bullets maneuvered independently mid-flight to accurately strike targets purposefully offset from where the firing sniper rifle was aimed.”  

“Wired reported in 2012 the first successful prototype test of the military’s first-ever guided small-caliber bullets, developed by Sandia National Laboratories and Lockheed Martin. Around four inches long, the bullets feature optical tips to detect laser beams shown on targets.”  

“Actuators inside the bullets then steer tiny fins on their surfaces, which guide them to targets based on information from the tip sensors.”