Ajustable power guns have a range of adjustment that exceeds the efficient possibilities for a given projectile weight. Example, a lightweight pellet will increase in velocity from a min power setting to aprox 30 to 50% of max settings, raising the power higher only wastes air and will not increase velocity significantly. A heavy bullet will increase velocity all the way to max setting with the below 50% being to slow to be effective. A midweight projectile will work best in the aprox 30 to 75% max power range, going to max will waste air unnecessarily. That range of efficiency per projectile weight is the effect adjustment zone for the projectile. This is especially noticeable on guns made to shoot bullets and pellets.