Targeting and patterning a shotgun
There are major differences in targeting shotguns and rifles. Shotguns are pointed at a target and shot with both eyes open; you focus 100% on the target itself. Rifles, however, are aimed by focusing your dominant eye through your scope or sight. The trigger pull on a shotgun is quick, often described as "slapping" the trigger. It is important to know your dominant eye when using a shotgun, because you will have both eyes open when taking a shot.
Shotguns usually are used for moving targets. Patterning a shotgun is a very important element in finding out how the shot charge is being affected by the load and choke.
To pattern a shotgun, take the following to the range: your shotgun, shotgun shells and some pieces of paper at least 40-inches square. When you pattern your shotgun, be sure the ammunition you use is the appropriate size and type of shot or projectile. Using different ammunition will affect the outcome of the resulting pattern. To assist in centering the pattern as much as possible on the paper, draw a black 2-inch dot in the center of the paper. Place the paper against an appropriate backstop at the maximum distance you expect to take your game; be sure to measure this distance accurately. If your pattern is found to be effective at the maximum distance, it becomes increasingly more effective the closer to the gun at which you shoot your game because the pattern will be tighter at the closer distance.
Step up to the distance line, aim at the black dot and fire. Then walk downrange and draw a 30-inch circle around the densest registration of the pellets on your paper. You can use a 15-inch string tied to a pencil or felt tip pen to make an accurate 30-inch circle. Hold one end of the string against the center of the densest registration or pellet holes and with your other hand swing the pencil or pen in a full circle. If you find your pattern is substantially off the paper due to aim error or flinching, you must reshoot the pattern.
To accurately evaluate your patterns, you must fire a minimum of three patterns of each load, shot size and choke at each distance of interest. This means one shot each at each of the three sheets of paper for a total of three shots to be averaged; never fire more than one shot at each sheet of paper. After firing your patterns mark through and count each pellet hole found inside or touching the 30-inch circle you have drawn on each of your three sheets of paper. Then average the three pellet counts to find the best load, shot size and choke to use.