Yabutt... Larry...
I was using a 60 fps speed differential at 40 yards, which Miller referenced using launch velocities of 1135 and 1330.
Your speed differential would be 1/4 of that, and 4x .06 is .24 which is (ta da) close enough to 20%.
For 7 1/2 that's actually significant.
Of course, larger pellets retain energy better which is one reason we use them.
I don't take issue with the light load crowd at all, and I use lighter loads when appropriate such as with lighter and older guns. Likewise, I try to limit range in that case. Again, I'm not out there to run.
Agree that heavy loads don't make up for lousy shooting.
