Why the Navy backed off railguns (and China should too)

The prototype Chinese railgun is the first technical demonstrator of the tech on a ship at sea, but there are real reasons why the Navy is slow-rolling the railgun, and it's unlikely that China has broken the code on how to make railguns viable.

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First, for anyone who isn't up on what railguns are, they're a type of naval artillery that uses massive amounts of electricity to propel the round instead of a chemical reaction (read: gunpowder). This would be a major improvement in logistics and safety as the Navy would no longer need to ship bags of gunpowder around the world, but the best advantages come in range and lethality.

Railguns can hurl rounds very far. Navy engineers have said they think they can reach 230 miles with current technologies. And when the rounds hit the target, they're going so fast that the total amount of damage on a target is like it was hit by a missile or a massive, high-explosive warhead but the fast-flying rounds can also pierce most armor and even underground targets and bunkers.

Oh, and the rounds are super cheap, costing about ,000 dollars per shot while the missiles they could sometimes replace are usually 0,000 a shot or more. Also, this hasn't been proven yet, but railguns might be able to fire as fast as every 6 seconds.

Rain. Of. Fire.

So, railguns can fire up to 10 times as far as conventional artillery with a safer round that does more damage when it hits the target. And this isn't theoretical — railguns have actually achieved these things in Navy tests. Time to put them on ships before China can, right?

High-speed photograph of Navy prototype railgun firing.

(U.S. Navy)

Not exactly. Because while railguns are a huge step up from conventional artillery and have a lot of advantages, there are also some serious drawbacks. First, they need a decent amount of deck space as well as a ton of space below decks. That's because the guns require a ton of electricity, up to 9 kilowatt hours per shot. That's how much energy an average U.S. house uses over 7 hours. The only surface ships with that kind of power on tap are the three Zumwalt-class destroyers and aircraft carriers.

Meanwhile, the weapons have improved in maintenance requirements in recent years, but still need new launcher cores every 400 shots and barrels every thousand.

But the biggest problem is the range. While a 230-mile range is phenomenal for artillery, it's still a paltry reach compared to missiles. Tomahawk cruise missiles can reach between 810 miles and 1,550 miles depending on the type, and China's "Carrier Killer" DF-26 is thought to strike at 1,200 miles or more. Meanwhile, a carrier-launched F-35 has a 1,380-mile range that can be extended with aerial refueling.

A railgun fires during testing at Fort Sill, Oklahoma, in 2016.

(Monica Wood, Fort Sill Public Affairs)

So, were railguns obsolete before they were launched? No. There are still plenty of niche uses for the railgun, and the Navy has slowed development but is still pursuing the weapon. Accurate railgun fire could intercept enemy missiles and fighter jets for cheap, possibly while plugged into the super capable Aegis combat system.

And while railgun-equipped ships would likely be too vulnerable to missile strikes to be "door-kicking" ships that take out enemy defenses on day one of a conflict, they would still be very valuable for shore bombardment, strike missions, and other tasks after the first week or so of a war, after the worst of the enemy's missiles are taken out.

So why is China pursuing the weapon so hard? It's unlikely that it has solved the power-generation problems of the railgun. And the U.S. is working hard to get the barrels right so they could fire 1,000 rounds instead of the 10 or less that were standard pretty recently. There's a chance that China is still struggling with that and similar problems.

An artist's illustration of a Navy Joint High-Speed Vessel with the prototype railgun installed for testing.

(U.S. Navy)

But being the first navy to put a railgun to sea has already granted China a pretty great and relatively easy propaganda victory. The country has worked hard on their technology in recent years in order to be seen as a great naval power, potentially positioning themselves as an arms exporter while deterring conflict.

And the U.S. will have to prepare for the possibility that the railgun is for real. The first pilots to fly within the ship's range if a war breaks out have to reckon with the possibility that a 20-pound shell might be flying at Mach 7 towards their aircraft at any moment. Missile attacks against a fleet with the ship will have to decide whether to concentrate on the railgun or an aircraft carrier or another combatant.

But, again, this could all be China exploring the tech or bluffing, but with none of the breakthroughs needed to make the weapons viable in combat. If so, they would be wise to concentrate on the many other breakthroughs their military could use for an actual fight.