It depends. Travel time is determined by the muzzle velocity, the ballistic coefficient (BC) of the projectile, etc. All of these properties can be drastically different from ship to ship.

Muzzle velocity is the speed of the projectile as it leaves the barrel. It's primarily determined by the weight of the projectile, the power of its propellant charge, and the length of the barrels from which they're fired.

-Lighter projectiles, stronger propellant charges, and longer barrels will tend to produce higher muzzle velocities. Compare something like the Germans, with their fast, light Ap shells, to something like the Americans, with their slower, lazier but heavier shells.

BC is the ability of the projectile to push through the air, and resist aerodynamic drag. A High BC is generally derived from "slick" aerodynamics, and a projectile that's long and heavy for its caliber. All other things being equal, a round with a higher BC is going to shoot "flatter." A round with low BC might leave the barrel fast, but will quickly begin to slow down due to drag.

Reload speed doesn't enter into it.