Soldiers have long dreamed of a smart bullet that always hits the designated target, and it looks like they are much closer to getting their wish. DARPA (Defense Advanced Research Projects Agency) has posted the first footage of EXACTO (Extreme Accuracy Tasked Ordnance), a .50-caliber bullet that uses optical guidance and sensors to home in on its prey. The 4-inch-long bullet has guidance and control electronics to steer its fins in mid flight as it homes in on a target. Continual course adjustment means the bullet can hit laser-designated targets at distances of more than a mile ― a huge leap over military assault rifles such as the M-16 that have an effective maximum range of just over a third of a mile. This is not one of those bullets that get their accuracy from spinning as they are fired out of a "rifled" gun barrel that has grooves to create the spin. Instead, it resembles a dart with a forward center of gravity and tiny fins that allow it to fly accurately without spinning. A tiny nose sensor allows the bullet to home in on laser-designated targets to deliver the accuracy and range of an expert sniper. As the bullet flies through the air, its early motions allow for course corrections 30 times per second.