The U.S. Navy in the early 2000s conceived of the DDG-1000 Zumwalt class of stealth destroyer as its main future platform for naval surface fire support. That is, shelling enemy beaches.

But the Zumwalt program collapsed. Citing rising cost and complexity, the Navy cut the class from 32 ships to just three. Now the Navy is left with the same old ships for fire support. The fleet’s only realistic chance of boosting its gunfire capability lies in a new kind of shell.

The California think-tank RAND in mid-2020 studied the fire-support problem. The resulting report is wide-ranging, but one conclusion is inescapable. The fleet’s existing ships in any high-intensity war quickly would empty their magazines while targeting enemy forces on the shore.

“Most of the scenarios we consider involve a considerable expenditure, and formal modeling against a plausible target set indicates a very high volume of munitions expenditures, generally beyond what would be carried in a ship’s magazine,” RAND explained.

The Zumwalt class was supposed to greatly boost the Navy’s ability to destroy coastal targets at long range. Each of the 16,000-ton-displacement destroyers packs two 155-millimeter cannons in theory capable of firing a precision-guided shell farther than 80 miles.

But when the Navy in 2009 cut the class to three ships, it lost economy of scale. The custom guided shells grew so expensive -- $800,000 per round -- that the fleet decided it no longer could afford them. The Navy has deactivated the guns, leaving the $7-billion Zumwalt with a strictly missile armament and a new mission: hunting other warships on the high sea.

In the Zumwalt’s absence, the fire-support mission fell to older Ticonderoga-class cruisers and Arleigh Burke-class destroyers. The Navy in 2020 operates 22 cruisers, each with two 127-millimeter guns, plus 67 destroyers with single 127-millimeter guns. Of those 111 guns, 50 are older Mk. 45 Mod 1 and Mod 2 mounts with 54-caliber barrels. The other 61 are Mod 4 mounts with longer, 62-caliber barrels that can fire a shell at a higher velocity.

The Mk. 45 boasts a maximum range of 13 miles and can sustain a firing rate of 20 rounds per minute.

A 10,000-ton-displacement Burke can carry 600 shells in its magazine. A Ticonderoga with a similar displacement can carry 1,200 shells. Assuming the ships can sail close enough to reach shore targets -- a big assumption considering the vessels’ deep drafts -- they could exhaust their magazines in one hour of steady firing, at which point they would need to rearm.

“These ships must be resupplied frequently,” RAND noted. “Resupply can be accomplished at sea via underway replenishment or by transiting to an available port. Either method requires resources and interrupts mission accomplishment. Considering all of these factors—in particular, the high demand of the platforms and their frequent need to resupply—availability of NSFS platforms presents a challenge.”

The Navy is trying to sidestep this problem by arming some of the ships with a faster, farther-flying munition. If it can shoot from farther off-shore with a more powerful shell, a warship might need to devote fewer rounds to a target -- and could stand-off at a greater distance, placing it closer to its resupply point.

To that end, arms-maker Raytheon is developing a so-called hypervelocity shell for the Mod 4 mount. With its more streamlined design, the $100,000 shell flies twice as fast as a conventional shell and can reach three times farther: around 50 miles.

The Navy isn’t saying much about whether and when the super-fast shell might enter front-line service. But it’s worth noting that, as recently as 2018, the destroyer USS Dewey fired 20 hypervelocity shells during a realistic war game.

Bigger ships with bigger guns might have been a better solution to the fire-support problem. But a better shell could work, too.

David Axe is defense editor at The National Interest. He is the author of the graphic novels War Fix, War Is Boring and Machete Squad.