Even the Defense Department, which consumes around $600 billion of the annual federal budget, draws the line somewhere: it won't spend $800,000 apiece on new intelligent artillery bullets that can hit targets nearly 80 miles away.

The Navy refers to the next-gen ammunition as "Long Range Land-Attack Projectiles," and until this week was planning on equipping its newest warship class with them. Citing excessive costs, the Navy will scrap those plans, Defense News reports.

The problem is not the cost itself, but rather economies of scale. Only three Zumwalt-class ships will be built, down from the 28 that were originally planned. But the cost of the bullet order has remained constant, ballooning to $800,000 per round.

"We were going to buy thousands of these rounds," a Navy official familiar with the program told Defense News. "But quantities of ships killed the affordable round."

The bullets themselves are precision-guided 155mm artillery shells. Inside each one is a GPS and an inertial navigation unit, which uses gyroscopes and accelerometers and is similar to the ones used on aircraft. All of the electronic components are designed to withstand the firing of a gun, presumably the principle factor contributing to the program's astronomical cost.

Bullets fired from multiple guns—each Zumwalt-class ship will have two—can be guided to strike the same target, or they can be split up to pummel multiple ones, according to their manufacturer, Lockheed Martin. They're designed to defeat targets in coastal cities, and they can be fired at a rate of up to 10 rounds per minute—that's $480 million per hour.

It's unclear what the Navy will use to replace the smart bullets in the three Zumwalt-class ships, although Defense News reports that it does intend to test the 150 rounds it already purchased once the first ship is launched.