http://www.paintballgun-airsoftgun.com/blog/post/3442087 Have you ever wondered why there are different sizes or weights for airsoft BB's? Well, the different weights of the BB’s are suitable for different situations. The lighter the BB, the less accurate your shot will be. Use a heavier BB, and you can be more accurate, but at shorter distances. So, you need to decide whether accuracy or distance is more important to you in your particular airsoft game.