Patterning a Shotgun
Most folks do not bother to pattern their shotguns. The reason for patterning a shotgun is the same reason for sighting in a rifle or handgun: establishing the point of impact and finding the best repeatable performance.
The benefits are many, including more birds in the game bag, elimination of wounding losses and less ammunition expended. Your dog will think more highly of you and you will be more satisfied with yourself.
STEP ONE: ESTABLISHING POINT OF IMPACT
You shoot your shotgun off of a rest at a 40 yard target, sighting straight down the barrel. Three shots at a four foot square piece of paper or poster board using a full choke will make it easy to see where your shotgun prints its pattern. Double-barreled shotguns should have barrels regulated within four inches of each other.
Do not let wind blow your mind A 10 mph cross-wind blows a 1200 fps pattern of #8 shot 9.1 inches at 40 yards. If you can, shoot on calm days. If you must shoot when a breeze is blowing, shoot directly into or directly with the wind to minimize its effect. Number 6 lead (or larger) shot is better for this task.
Many shotguns do not shoot to point of aim. Close to half of the shotguns I test do not. This may be corrected by warranty, bending barrels (Tony Knight's favorite method), or eccentric chokes. For flushing game, I find anything from essentially flat to about 3 inches high at 40 yards as ideal: the 60/40 percent pattern.
STEP TWO: DYNAMIC POINT OF IMPACT
After you have a confirmed shotgun that shoots where pointed, repeat the process off-hand. Results should be similar, otherwise there is a gun fit issue.
STEP THREE: PATTERN EFFICIENCY
You want about a 99% chance of a three pellet critical strike (or better) at the range you are shooting. It is the combination of a quality shell and a quality choke that accomplishes this. Once you are satisfied, you have completed this one time process for the intended application. You can count pellets manually, or use the TurboTarget system by Target Telemetrics that will quickly give you precise, detailed information.
A TRUE TURKEY STORY
A friend related the example of an avid turkey hunter, using a heavy load of #6 shot and a modified choke that bagged his two turkeys every year. These were typically called to within 25 or 30 yards. However, he decided that he wanted a denser pattern from a Turkey Choke. He installed it and proceeded to miss turkey after turkey. His patterning method was shooting at cattails or water and calling it good.
When his shotgun was actually patterned, the Turkey Choke was doing its job. However, his shotgun shot 14 inches high at 40 yards. With his old, wider pattern choke, he was bagging turkeys, but only with the lower 25 to 35 percent of his pattern. Buy using a dedicated Turkey Choke, his patterns were tremendously tighter, but he was shooting over his birds. His pattern was far denser and, of course, far smaller. The bottom line: it pays to properly pattern shotguns.
A fellow that goes by the handle "GF1" mentions patterning as I have, but as a four-step process, specifying double-barreled shotguns as a distinct point #2:
"As a sporting clays instructor and a part time manager at a large shotgun shooting center, I am regularly amazed that so few of the folks who come to pattern their shotgun have any idea what they are looking for, or why they are doing it. It boils down to four specific reasons:
1) Evaluating if the gun it technically/mechanically shooting where it is aimed, aiming the shotgun at a point on the pattern paper as one would a rifle. If this test fails (the pattern center is significantly different than point of aim) the gun is faulty and needs a fix.
2) Related to #1 above, a double shotgun is aimed as above, each barrel shot several times on the same sheet to evaluate POI/POA differences. Point is to evaluate barrel convergence; that both barrels shoot to the same place, which should be very close to POA.
3) Patterning for stock fit. Much different than above, as this is shot very quickly, multiple times and without aiming while looking intently at the center of the target. The point of this effort is to adjust/verify fit of stock to ensure the pattern hits where its pointed. I do this at 16 yards, so it is easy to move the pattern center one inch by moving the comb 1/16 inch.
4) Pattern quality evaluation."
Copyright 2015 by Randy Wakeman. All rights reserved.