Offhand, I can think of three ways to steer this bullet onto its target: * Aero-fins * Compressed air jets * Gyroscope The mock-ups don't show any fins. That doesn't necessarily mean they aren't used. Compressed air jets would require small holes in the sides of the bullet. A gyroscope would be a marvel of miniaturization. I'm wondering what one of these bullets costs? A possible fourth method occurs to me as I write this: * controlled mass shift within the bullet