Comment Re:Beating physics (Score 2) 517
There are two other, very large factors - the cost (energy, fuel, time, human and other resources) of getting the ammunition and the propellant to the battle, and the safety. The fuel to drive the ammo supply ships has to be taken into account. A given ship is expected to be able to carry four times as many rounds of railgun ammunition vs. standard ammunition, eliminating two or three supply runs, and possibly dangerous deliveries between ships in the middle of the ocean. Ammo ships are notoriously bad duty in real wars, and if you look through WWII naval battles it is quite common for the killing blow to a ship having been penetration and detonation of one or more magazines.
From a _systems_ point of view (which is the Navy's POV on this), the cost of railguns will be much less. While at present manufacturing cost of the projectiles is high, it's already competitive with equivalent damage-producing shells. And passive solid tungsten projectiles could become quite cheap once the high precision high volume manufacturing gets in gear.