The U.S. Pentagon has fallen in love with electromagnetic railguns, and that could mean billions of dollars in contracts for the several companies working on the initiative.

Video source: U.S. Navy.

But what is a railgun anyway? And which companies -- which stocks -- stand to benefit most from the U.S. military adding this new weapons system to its arsenal? I did a little digging, and here's what I've come up with: 21 fascinating facts about the electromagnetic railgun.


1. It's not your father's cannon. Conventional cannons ignite a modern variant of gunpowder to propel explosive shells at targets located miles away. A railgun operates differently, using electricity from powerful generators to accelerate a non-explosive projectile along electrified rails.

2. How it works, specifically. Electricity is run into one rail within a railgun's barrel, routed through the projectile itself, and into the second rail. Continued application of electrical current accelerates the projectile down the barrel, gaining speed all along the way.

3. It's faster than your father's cannon. Lacking a warhead, a railgun projectile derives its destructive force from its speed of movement -- kinetic energy. The railguns the Pentagon is developing are designed to accelerate projectiles to a top speed at roughly Mach 6 -- 4,500 miles per hour. 

4. It's faster in other ways. The 16-inch Mark 7 aboard America's old Iowa-class battleships fired two rounds per minute. America's new railgun is being designed to fire as fast as 10 times per minute -- a factor-of-five improvement.

5. It "shoots" farther, too... The Mark 7 cannon had a top range of 24 miles. In contrast, the railguns the Navy is designing will reach targets as far as 125 miles distant -- another fivefold improvement.

6. ...partly because its "bullets" weigh less. Shells fed into the Iowa's cannon weighed as much as 2,700 pounds each -- about as much as a 2016 Honda Civic. In contrast, a railgun projectile weighs just 25 pounds.

7. As a result, it can hold more bullets. Thus, any given warship can carry a whole lot more railgun projectiles in its munitions locker than it can conventional artillery shells. For any given amount of firepower desired, a railgun-armed warship can therefore be built smaller (i.e., cost less), require less frequent resupply (i.e., cost less), and be faster and harder to hit (i.e., need less frequent replacement -- and so cost less) than a WWII-era battleship.

8. Did I mention it costs less? Conventional cannon shells can't shoot as far as railgun projectiles. To match the range of a railgun projectile, you basically need to launch a self-powered cruise missile such as Boeing's (NYSE:BA) Harpoon, the latest version of which can strike targets 134 miles away -- but costs $1.2 million. In contrast, a railgun projectile costs just $25,000.

9. Small things come in small packages. Projectiles aren't the only things which are smaller and more efficient. The railgun itself has a smaller footprint than previous cannons. Stretching 32 feet in length, the barrel of a railgun is less than half as long as the barrel on an old Mark 7.

10. They play offense, and defense too. Traditional cannons have just one purpose: to blow stuff up. Railguns' cheap price tags and vastly greater range (and speed) permit them to assume a dual role. They can attack hostile warships and ground targets, yes. But they can also be used to shoot down incoming cruise missiles, and potentially aircraft and drones as well.

11. All these capabilities require power. A lot of power. Powering the electromagnetic railgun requires access to a power plant generating 25 megawatts of electricity. Thus, it's only practicable to install railguns aboard large warships (or perhaps coal plants).

12. Only a very few warships currently exist with power plants big enough to operate a railgun. Spearhead-class expeditionary fast transports (EFTs), for example, are powered by four Rolls-Royce (NASDAQOTH:RYCEY) MTU 20V 8000 M71L diesel engines, producing 9.1 megawatts of electricity each -- so 36.4 MW total. Zumwalt-class battlecruisers sport even mightier Rolls-Royce MT30 gas turbines putting out 35.4 MW of juice each (plus supplemental Rolls-Royce RR4500 generators, rated at 3.8 MW apiece).

13. 21 railguns...? Mathematically speaking, this suggests it's theoretically possible to install a railgun aboard each of the planned Spearhead-class EFTs, and up to three railguns aboard each Zumwalt. That's 21 railguns total that the Navy might buy.

14. ...or more? Of course, that's just how many railguns the Navy could power using dinosaur juice as the propellant. Each of America's 10 operational aircraft carriers is powered by a 100 MW A4W nuclear reactor, which could conceivably support up to four railguns firing simultaneously. Each new Ford-class supercarrier will sport a new A1B reactor with three times the electrical output -- a potential dozen-gun electromagnetic railgun boat.

15. Lots of guns means lots of money. The Pentagon has already sunk $500 million into developing an electromagnetic railgun, and expects to spend $800 million more to make the weapon operational.

16. Money for BAE Systems. General Atomics and BAE Systems (NASDAQOTH:BAESY) are the two main contractors building prototype railguns for the Navy to test. One or both might eventually be awarded production contracts -- but because BAE Systems is the only one publicly traded, it's the only one you can invest in. (That's not necessarily a bad thing, because BAE is also making projectiles for the railgun -- making a win for it a twofer.)

17. Money for Northrop Grumman. Northrop Grumman (NYSE:NOC) is working on the electronics that will be used to guide railgun projectiles in flight. It's not an easy job, because these electronics must be hardened to withstand multiple g-forces of acceleration, and must also be able to receive communications in flight -- communications which must pass through a plasma trail of superheated air surrounding the fast-moving projectile.

18. Money for Raytheon. Since at least 2011 Raytheon (NYSE:RTN) has been working on the integrated power system and "power load module" to help fire railgun projectiles. It's a small but critical part of the entire project.

19. Money for Austal. Australian shipbuilder Austal (NASDAQOTH:AUTLY) builds the Spearhead-class EFTs, one of only a handful of platforms capable of generating the power needed to host a railgun.

20. Money for General Dynamics. The other shipbuilder is General Dynamics (NYSE:GD). GD builds the Zumwalt-class battlecruisers which may be able to carry multiple railguns.

21. Money for Huntington Ingalls. Since power appears to be the most relevant restriction on widespread railgun deployment, Huntington Ingalls Industries (NYSE:HII) may be the most obvious beneficiary of this "drawback." Huntington builds the Navy's nuclear-powered aircraft carriers, the platform that, in theory at least, could carry the most railguns per ship. Huntington Ingalls also builds nuclear-powered submarines, so ...

Nuclear-powered, underwater railgun boats, anyone?

Submarine Art
Image source: Getty Images.

Fool contributor Rich Smith owns shares of Raytheon. You can find him on Motley Fool CAPS, publicly pontificating under the handle TMFDitty, where he's currently ranked No. 298 out of more than 75,000 rated members.

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