Rail Guns achieve much greater velocities than conventional chemical propellant guns - and these velocities suggest that there will be no need for high explosive shells - as the kinetic energy of the projectile will be so destructive on terminal contact.
We're talking here about velocities in excess of 2.4 kilometres per second. (Mach 7). - And ranges out to 100 miles.
A 'single loop' rail gun requires a launch current of a "few million amperes" - Although there is no chemical 'explosive' propellant involved - the heat generated by the speed of propulsion is considerable.
Researchers were aiming for velocities of 11,500ft/per/sec (Mach 10) - Yugoslavian researchers are already seeking 23,000 ft./per/sec.
These extreme high velocities not only mean that explosive laden warheads are not needed - but also mean that the launch vessels will not need any 'magazines' full of explosive propellants on board either - reducing the threat of catastrophic on-board fires. - Think nuclear powered electricity generators on-board warships.
- DDG 1002 was named 'USS President Lyndon B. Johnson' in April 2012 - after the 36th President of USA.
I'd guess that portable 'rail gun rifles' might be just around the corner too (- think modern re-chargeable electric battery development). - forget case-less ammo and 3D printed guns!