There are plenty of rifle rounds with very low bullet drop rates. For example, the 26 Nosler has close to zero inches of drop at 450 yards (quarter mile.) By ex

There are plenty of rifle rounds with very low bullet drop rates. For example, the 26 Nosler has close to zero inches of drop at 450 yards (quarter mile.) By extending the turret's barrel length and adding additional rifling/twist, drop can be further decreased while power is increased. Unless the distances are greater than a mile, a high powered rifle round will have so little drop to be negligible. And a railgun could be used if the energy footpounds of smokeless powder is not cutting it -- but really, a small grain round with a large powder charge will fly straight for the distances we are concerned with here.