Sandia National Labs maintains the project, with Red Jones and Brian Kast as main developers.

The four-inch bullet uses optical sensor in its nose to follow a laser beam  to its target, similar to the way a laser-guided bomb finds a target.

In order to enable a bullet to turn in flight and follow a target and to simplify the design, the usual bullet spinning caused by the most rifle barrels was removed.”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.” Red Jones said.

The prototype does not require a device found in guided missiles called an inertial measuring unit, which would increase significantly its price. Plastic protectors provide a gas seal in the cartridge and protect the delicate fins until they drop off after the bullet emerges from the firearm’s barrel.

Computer simulations discovered that unguided bullet into real conditions could deviate by 9.8 yards (9 m) from its target, launched from more than a half mile away (1,000 m away).  In comparison, a guided bullet would get within 8 in (0.2 m), according to the patent.

In guided missiles, corrections of flight take effect relatively slow, so each correction needs to be very precise because only a few corrections are possible during flight. But “the natural body frequency of this bullet is about 30 hertz, so we can make corrections 30 times per second. That means we can over-correct, so we don’t have to be as precise each time,” Jones said.

Testing has shown the electromagnetic actuator performs well and the bullet can reach speeds of 2,400 ft/sec, or Mach 2.1, using the most common gunpowder. The developers are sure it could reach standard military speeds using customized gunpowder.

via :[defencetech.org]