Albuquerque, NM--Sandia National Laboratories researchers Red Jones, Brian Kast, and their colleagues have invented a finned self-guided bullet for small-caliber, smooth-bore firearms that could accurately hit laser-designated targets at distances of more than a mile.
The design for the four-inch-long bullet includes an optical sensor in the nose to detect a laser-beam spot on a target. The sensor sends information to guidance and control electronics that use an algorithm in an 8-bit CPU to command electromagnetic actuators. These actuators steer small fins that guide the bullet to the target with a flight-path-correction rate of 30 times a second.
No rifling
Most bullets are shot from rifles that have grooves, or rifling, that cause them to spin so they fly straight, like a long football pass. To enable a bullet to turn in flight toward a target and to simplify the design, the spin had to go, said Jones. The bullet flies straight due to its aerodynamically stable design, which consists of a center of gravity that sits forward in the projectile and tiny fins that enable it to fly without spin, just as a dart does, he said.
A nighttime field test in which a small
LED was attached to the bullet showed the battery and electronics can survive flight, Jones said. Researchers also filmed high-speed video of the bullet radically pitching as it exited the barrel. The bullet pitches less as it flies down range, a phenomenon known to long-range firearms experts as “going to sleep.” Because the bullet’s motions settle the longer it is in flight, accuracy improves at longer ranges, Jones noted.
