I am doing a science project and need a few questions answered. I am trying to theoretically determine which caliber of bullet is capable of travelling the farthest. I've already assumed that the time each caliber of bullet spends in the air is going to be exactly the same. Therefore, I'm assuming each bullet is shot perfectly horizontally at an altitude of 9.8 m, so each bullet hits the ground in 1 second. To determine the distance each bullet travels, I need the velocity. I'm aware of theexit velocities of each caliber of bullet. But while some bullets may exit the barrel faster than others, drag slows each one down at different rates. I was wondering if anyone could get me an equation that I could use to determine the deceleration due to drag for each caliber of bullet.