I wonder what the effective range of this thing actually is because the curvature of the earth is going to come into it when talking about these distances. The

I wonder what the effective range of this thing actually is because the curvature of the earth is going to come into it when talking about these distances. The curvature is roughly 8 inches per mile, ~1 meter per 5 miles. Something 6 stories tall (~18 meters), like say a large capital ship would be below the horizon if it was 90 miles away. Granted rail guns don't shoot in a straight line but you aren't going to get much ballistic drop in the time it takes a Mach 7 projectile to get to its destination... Mounting the gun higher on the ship would help, but then you are dealing with a very large equal-and-opposite force high above your center of gravity... [EDIT] On second thought, with a velocity of 1.48 miles per second you are talking about 81 seconds of flying time at it maximum range, which is quite long enough for our friend gravity to drop the projectile and "bend" it around the horizon. Holy shit that's pretty incredible.