Here is a simple question. If I pattern a gun at 32 yards and the center of the pattern is 8 inches above my point of aim what approximate percentage does the barrel shoot ie 70/30, 80/20 etc and how does one calculate it? Thanks. bob
I like patterning at 20 yards, you are half way to 40 yards. Anything that is 4" high at 20 yards will be basically 8" at 40 yards. There is a bit of drop but it is an easy way to see how high a gun shoots.
The pattern is small at 20 yards and it is very easy to draw a circle around it and see where the centre is.
Shoot at a 2 inch round dot from 40 yards. Form a snowman with the beads and hold at the bottom of the dot. If the greatest concentration of shot is around the dot the gun is shooting 50/50. For every 3 inches high it is shooting add 10 percent. 9 inches high would be 80/20. 15 inches would be 100%. I just lowered my gun to 80/20 from 90/10. Low targets on windy days were killing me. It is better now.
Hap, Longshot, and stilltrying are all correct. But keep in mind any change in size and weight of shot, velocity, wads, hulls, primers, powder, will dramatically effect pattern size and density. Not to mention gravity. Size 7-1/2 shot at 1200 fps. drops 6 inches at 60 yards!
Like Hap, I prefer inches above POA. However, 8" high at 32 yards is about 10" at 40 yards- THE standard distance pattern percentages are derived from. 10' @ 40 is a touch more than 80/20 (standard stylized 30" pattern @ 40 yards).