I've honestly never used a circle, of any size, and counted hits. I'm a retired electrician and have plenty of old blueprints. I'll use the backside on one of those pages, trace out my arm with a marker from the elbow area up to my hand made into a fist and rotated down to simulate a turkeys head and neck. Then I shoot those at different yardages to figure out how far would be too far just by looking at the pattern. Worked well for me all these years...
