That is what I was taught so many years ago. My teacher an older family friend called his load a square load the same volume of powder and shot. So if you are shooting 70 gr of FFG (2.5 drams) by volume and using #4 shot the same measure will be used for the shot. I have used all sorts of wadding/over shot cards and it does not seem to matter.Rob all the testing I’ve done I’ve come to the conclusion that it’s mainly the powder charge that makes the biggest difference in a shot load