Terminal velocities of bullets vary by caliber, but can reach 300 to 700 feet per second. For example, a .30 caliber bullet's terminal velocity is 300 feet per second. If the bullet is shot at an angle and keeps its arc, it is more likely to reach terminal velocity.
The terminal velocity of any given bullet can be determined with a simple physics equation: velocity equals the square root of twice the weight divided by product of the drag coefficient times gas density and frontal area. Aerodynamics of the bullet impact its terminal velocity as much as its mass and conditions of firing.