ALBUQUERQUE, N.M. — Figuring out how to pack a processor and other electronics into a machine gun bullet has been a challenge for engineers at Sandia National Laboratories, so weapons experts say the miniature guidance system the lab has developed is a breakthrough.

Three years in the making, the bullet prototype represents another step toward a next-generation battlefield that scientists and experts expect to be saturated with technology and information.

"In the laboratory, I'm able to make machines so incredibly small it kind of boggles my mind," said Red Jones, one of the Sandia researchers who helped develop the laser-guided .50-caliber bullet. "Where we're headed, we're going to be limited only by our imagination."

Developing more precise weaponry has been a mission for government and industry scientists for decades. Most recently, the research arm of the U.S. Department of Defense has awarded tens of millions of dollars in contracts to companies to develop guided ammunition for snipers and special scopes that account for crosswinds and other environmental variables.

The idea behind Sandia Labs' bullet is rooted more in the M2, a belt-fed machine gun that became standard issue in the U.S. Army nearly 80 years ago. Pairing the M2 with the guided bullet would allow soldiers to hit their mark faster and with precision.

At 4 inches long and a half-inch in diameter, the bullet directs itself like a tiny guided missile and can hit a target more than a mile away.

It's designed to twist and turn, making up to 30 corrections per second.

"Everybody thought it was too difficult to make things small enough. We knew we could deal with that. The other thing was it was going to be too complicated and expensive," he said. "We came up with an innovative way around that to make it stupid and cheap and still pretty good."

Jones and his fellow researchers had initial success testing the design in computer simulations and in field tests of prototypes, built from commercially available parts.

With most of the hard science done, Jones said the next step is for Sandia to partner with a private company to complete testing of the prototype and bring a guided bullet to the marketplace.

More than $1 million in research and development grants have taken the project this far.

Computer simulations showed an unguided bullet under real-world conditions could miss a target more than a half mile away by nearly 10 yards. But according to the patent, a guided bullet would get within eight inches.

The design for the bullet includes an optical sensor to detect a laser beam on a target. The sensor sends information to guidance and control electronics that use an algorithm in an eight-bit central processing unit to command electromagnetic actuators. The actuators steer the fins that guide the bullet.

Jones said there are still some engineering problems to be sorted out that will make the bullet more practical — for example, it will have to be tough enough to be dropped off the back of a truck and still work.

Even more innovation is needed for the manufacturing process.

"What we want to do is make it cheap enough to make it cost effective for the military to use in a machine gun," he said. "It's not going to be millions of dollars, but it's not going to be a buck a piece either."

The technology has captured the interest of weapons experts, both for the successful miniaturization of guidance systems that are usually reserved for missiles and for the potential benefits of precision.

"All of a sudden now you've got a way to eliminate the collateral damage issues. From that perspective, this starts to get interesting," said Adam Firestone, an Army veteran, instructor and a weapons system engineer.

Firestone and other experts said the battlefield of the future will surely include more capabilities for guiding bullets and bombs, but what will make the difference will be communication improvements and intelligence sharing systems that take advantage of the high-tech weapons while linking each soldier together.

Defense department researchers and contractors are already developing flying nano-bots that can stream live video, contact lenses that would allow soldiers to focus simultaneously on virtual digital images and their surroundings, and smartphone apps that help with tactical operations.

"Where we're going is to a world where the individual soldier, Marine, sailor or airman lives in a bath of knowledge. The world would be surreal in the original sense of super real. When you look at something, you see what you need to see when you need to see it," Firestone said. "They will have the ability to make decisions more accurately and that will have a significant impact."