Velocity

Velocity is the speed of a projectile fired from a weapon. It shouldn't be confused with use time, which is the speed of which an item can be used. For example, the fire rate of the Megashark would be its use time, while how fast the bullets travel as they are fired would be the velocity. Velocity has no effect on damage; an arrow fired from the same bow will do just as much damage hanging in the air as it would rocketing towards its target.

The higher your weapon's velocity, the sooner you will hit your target and you won't have to "lead" your shots nearly as much if you're trying to hit a moving target. This is an advantage that may prove very useful when fighting bosses. Different weapons can fire at higher or lower velocities in and of themselves. Weapons that use arrows essentially fire at lower velocities but do more damage. In contrast, bullet firing weapons fire at higher velocities but don't do as much damage. The difference is substantial when using a bow for a while and then immediately switching to a gun. Modifiers and different kinds of ammunition can affect your weapon's velocity for the better or worse. Some weapons don't always have constant and consistent velocity patterns. For example, the Demon Scythe fires a projectile which starts out with minimal, but slowly increasing, velocity.

On another note, bullets and some magic projectiles, among a few others, are not affected by gravity; they will maintain their velocity as you shoot straight up as opposed to slowing down and eventually falling. This can be considered an advantage for guns that makes up for its inferior damage.