How Much Force Exerts on a Bullet in a Rifle Barrel?

[SailorMoon14]

A 4.5 g bullet leaves the muzzle of a rifle with a speed of 318 m/s. What force (assumed constant) is exerted on the bullet while it is traveling down the 0.75 m long barrel of the rifle? The answer is in Newtons.

Thanks for any input :)

 

[Galileo]

What do you know about the bullet after a constant has force as acted upon it over a given distance? (force times distance = ?)