Hitting a moving target is nearly impossible if you aim right at them. The bullets take far too long to hit, as they’re not hitscan like in other FPS titles. As such, you need to lead your shots to hit. If an enemy is 100 meters away, lead your shots by a gap of one person, and at 200 meters, two people between your target and the scope. This might be different for every weapon, as all of them differ in bullet velocity.