How do I make my Ion consistently shoot straight?

The Ion will shoot inconsistently for a number of reasons. An easy fix is to check if your paintballs are .68 caliber. Different paintball sizes can cause paintballs to break inside the breech and shoot inaccurately. Make sure that your air tank has plenty of air and is tightly fastened into the Ion. If your Ion's battery is low, the gun will gradually fire more slowly. To fix this, check out the battery replacement guide. To adjust the fps, use a 5/8" inch wrench to adjust the black hex nut located under the front grip. Be careful to adjust the velocity in small increments. It is important to take 5-10 shots in between adjustments to allow the regulator to adjust to the new pressure. Turning the black hex nut clockwise adjusts the velocity up, and turning counter-clockwise adjusts the velocity down.