I always hear everyone say that the various lighted nocks make no difference in arrow flight. How can this really be the case? When you are adding 16-24 grains to the very end of an arrow, how can that not make a pretty significant difference in flight, especially at longer distances? I can understand flight being the same at 20 yards or so, but is it really the same out to 40 plus yards? Anybody done any good field tests?