I was at an L.C. Smith shoot Monday, one of the memebers of my squad and I were talking about some light loads, he uses 3/4 oz loads for his 12 ga. He uses a Claybuster wad. I was using 7/8 oz. loads because at the time, I didn't have the right wad for the 3/4 oz.
We got talking about velocities and he had read somewhere that the lead between 960 fps and 1300 fps at 21 yards is the difference of 3.5 inches.

David