According to tests run by Sam Fadala, the .54 holds its velocity and trajectory better than the .50 or .58 or larger, due to weight and air resistance. By his tests the .54 would be the optimal RB for 100yd shooting if trajectory and retained energy is a factor. The smaller balls lose velocity from lack of weight, and the heavier balls lose velocity from having more weight and air resistance. According to Sam's testing. Personally, I do not think you would have any problem with a .50, if that is what you decided on.