If I'm reading the technology right, basically this is a very high powered catapult, meaning it's fire and forget, straight line trajectory so anti-aircraft and missile defense uses are neigh unto impossible as there would be no way to "direct" the round or have it home like radar, sonor, laser, video and fly by wire munitions.
From the article:
U.S. Navy commanders ultimately want a weapon capable of firing up to 10 guided projectiles per minute at targets up to 100 miles away.
Not
aimed projectiles,
guided projectiles. The only propulsion they would have would be that which they get from the initial firing. But they can still be guided projectiles in much the same way we have guided gravity bombs. They could use camera, radar, laser targeting, ground mapping with inertial nav, GPS, or a combination of these for guidance (like Boeing's JDAM package).
Railgun projectiles could look something like this:
For comparison, a MK-84 JDAM. A 2000lb
guided gravity bomb with GPS/Inertial Nav and Laser Targeting.
Punching through the side of the target is just fine. Having penetrated, your metal slug is now fracturing, rolling, tumbling and ricocheting around inside a big metal or concrete box. Mayhem ensues.
Yup! In mechanical and military parlance, we call it
"spalling".
That doesn't directly translate to recoil. Equal and opposite reaction as a concept is misleading in some cases. A bazooka has practically no recoil at all in comparison to with how much power it unleashed its projectile with, and yet equal and opposite reaction fully applies. There are guns which are designed to dissipate the 'opposite' force so that when you fire them the accuracy isn't affected, because the 'recoil' isn't all in the backwards direction. They call it recoil reduction.
Well, a bazooka has very little recoil because 1) the propelling force is internal to the projectile (unlike the rail gun); and 2) the rear of the launch tube is open, so the force of the rocket engine does not directly interact with the launch tube - if the back of the tube was closed, then the person holding the weapon would experience the full recoil of the rocket (which would be extreme to say the least, at least until the launch tube exploded...)
With the rail-gun, the force to propel the projectile is coming from the rails affixed to the inside if the weapon. Picture it this way, in much the same manner as a balloon squeezes out the air inside it (though equalization of pressure is also involved), and thus propels itself in an opposite direction - the magnetic fields of the rails are squeezing out the electfrified projectile (which now has it's own magnetic field), while much like the balloon, the weapon itself is propelled in the opposite direction (except that the gun is affixed and has mechanisms to disipate the recoil).
