AGS, Thanks. I used 1200 fps to make the math easy for myself(most loads tested were faster). I was basically saying that (i believe the approximate string length @ 40yds) was 10 feet, and that helped my math too, but the string made little difference to the target. Even it was moving 40mph. Lead is another factor of course but thinking of lead as a number of feet in front of the target is not very practical in real shooting IMHO. Your math said what I want to.