The Gun That Fires a 25-Pound Bullet

Let’s look at a big gun today. I mean a really, really big gun.

It can fire a 25-pound projectile through seven steel plates and leave a 5-inch hole. Whereas the speed of most bullets and shells is measured in feet per second, this gun’s projectile leaves the muzzle of it’ 32-foot barrel at 4,500 miles an hour, which is faster than a mile per second.

Not only that, but it has a range of 125 miles (for reference, that means a projectile fired from Washington D.C. could reach Philadelphia) and doesn’t rely on any conventional propellant, meaning a ship capable of carrying 96 missiles could keep up to 1,000 rounds on board, which can be fired at a rate of 10 rounds per minute.

Those are some of the attributes of the U.S. Navy's impressive new railgun, which the Wall Street Journal is calling a Supergun, recalling some of the monstrous propellant-fired guns built in WWII before rocket and missile technology made them obsolete.

Graphic from the Daily Mail.

It uses electromagnetic rails to accelerate a hardened projectile to a staggering velocity, "a battlefield meteorite with the power to one day transform military strategy, say supporters, and keep the U.S. ahead of advancing Russian and Chinese weaponry," says the WSJ. And the railgun is expected to be deployed within the decade.

The Navy has been developing the railgun for 10 years as a potent offensive weapon to combat enemy ships, destroy tanks and level enemy camps, the story says. Pentagon officials say in the story that the weapon, being called the most powerful gun ever built, has potential to knock enemy missiles out of the sky more efficiently and accurately than current missile defense systems.

The weapon still has some technical barriers it has to work out before it's battle ready, and policy makers have to weigh some geopolitical consequences of deploying it. For instance, the story says Russia and China see the railgun, and other advances in U.S. missile defense, as upending the world's balance of power because it negates their own missile arsenals. It also says there have been attempts by Chinese hackers to penetrate Pentagon computer systems and those of defense contractors to probe railgun secrets.

Check out this ultra-high-speed footage of the projectile from WSJ:

“Part of the reason we moved away from big guns is the chemistry and the physics of getting the range,” said Jerry DeMuro, the chief executive of BAE Systems, a railgun developer. “The railgun can create the kind of massive effect you want without chemistry.”

For contrast, the Navy’s current 6-inch guns have a range of 15 miles. The 16-inch guns once mounted on now-mothballed WWII-era battleships had a range of 24 miles and could go through about 30 feet of concrete. The railgun has five times the range and five times the impact of those old 16-inch guns.

In some ways, the railgun adopts the same philosophy that the M16 chambered in 5.56/.223 did when it was adopted as a rifle platform that fired a smaller, but faster bullet than previous battle rifles, and in a higher volume.

The U.S. Navy's railgun will be part of a new missile defense system within the decade, says the Pentagon.

“Anytime you have a projectile screaming in at extremely high speeds—kilometers per second—the sheer kinetic energy of that projectile is awesome,” said Deputy Secretary of Defense Robert Work. “There are not a lot of things that can stop it.”

In fact, we may have the wave of current consumer tech to thank for the hurdles the railgun has overcome, especially when it comes to its projectile, which is kind of a smart-shell that can be steered using GPS technology.

“Ten years ago, we wouldn’t have been able to build a projectile like this because the cellphone industry, the smartphone industry, hadn’t perfect the components,” said William Roper, director of the Pentagon’s Strategic Capabilities Office. “It is a really smart bullet.”

The Navy's new Zumwalt-class of Destroyer is the only ship with a large enough power plant to charge the railgun.

The WSJ notes that the railgun has a little ways to go before it because a battlefield reality. For instance, the story says its guidance system is almost complete, but not quite, and the circuits within the projectile have to hardened to withstand the incredible gravitational forces they are exposed to when the gun is fired. Also, the current power requirements of the railgun, which are enough to power 18,000 homes, mean it can only be mounted on the Navy's newest class of ship, the Zumwalt, of which only three will be built. But at this point, it seems to be an inevitability.

“You can’t ignore the fact that Russia has great ability to mass conventional munitions and fire them over great range. We have to be able to fight through those salvos,” Work said. “And the railgun potentially will give us the means to do that.”

With all that tech, they may sound like some expensive shells, and they are, but they’re still a bargain.

The story says the projectiles, which may actually be put into use before the railgun, are filled with tungsten pellets and will cost between $25,000 and $50,000 a pop. But that's a drop in the bucket compared to the $10-million per unit cost of the Interceptor missile. The Pentagon is working to adapt the projectile for use in existing Naval guns on vessels outside the Zumwalt class as well as for Army artillery applications.

While slower than a railgun, a powder-fired railgun projectile still flies at 2,800 mph, the story says, which would greatly extend the range of current big guns.

“At Dalhgren last year, military engineers test-fired 5- and 6-inch Navy guns loaded with a version of the railgun projectile. The range of the Navy’s 6-inch guns was extended to 38 miles from 15 miles. The Pentagon also tested the railgun projectile in 155mm Army howitzers, successfully extending its range.”

Here's some simple animation of how the railgun works, from the Wall Street Journal: