[Eclipse666]

first of all, you example doesn't make sense, a wiffle ball looses all of its energy extremely fast, and the faster you throw it, the faster its energy is dissipated because of air, because air, like water, resists more, the more you push.
For example, getting a car going 90kph takes less energy than getting it to go from 90 to 120, because the faster you go, the resistance of the air goes up exponentially.

a wiffle ball has little mass, thus little inertia when moving, so it can't keep its speed, or energy for very long. so no, i am not saying that. .. even though the energy contained within the two bbs is the same, the .2g bb would loose all of that energy very quickly, and just float with no accuracy, while the .25 or .3 would slowly loose its energy over a longer distance. since the l96 is a sniper rifle, i am not planing on shooting from very close, so a heavier bb would get to the target, and in the process, lose enough energy to make it less dangerous than shooting a lighter bb faster and closer
no need to get snippy