Even as I write this, I have to admit there are shotguns in my gun safe that I haven't patterned, and that I use for shooting and hunting. I shoot reasonably well with them and usually manage to break a few clays or bring home a bird or two from the field. We're fortunate that factory-made guns are generic enough in their dimensions that when combined with a pattern of decent size and density allow us to make hits, even if they might be at the edge of a pattern. But every time I miss a rooster or knock just a chip from a clay bird on a shot that "felt" right, I have to wonder if it was me, or if the load I was using didn't perform the way I thought it would. When I get around to patterning those shotguns, I'll know that answer. Why Pattern?

Patterning is done at 40 yards unless you're shooting .410-bore shotguns or "skeet" chokes. In those instances, pattern at 25 yards.

There are two fundamental reasons for patterning a shotgun. Foremost is to find where the shotgun puts its pattern relative to where you point it. Second, patterning will show you how a certain shotshell patterns with a given choke or choke tube.

With shotguns, your eye is the rear sight so every time you mount the gun, wherever you plant your face on the stock determines the setting of your "rear sight." If you mount your gun consistently, your shots will be consistent. Fuller faces tend to position the eye more to the left causing shotguns to pattern to the left, while long faces can cause a gun to shoot high. Naturally, the reverse is true. Custom-fitted shotguns are made to the physical dimensions of a shooter so that the gun patterns where the shooter wants it and many new shotguns come with shims to allow the user to make some adjustments. Even shotguns with fixed buttstocks are capable of being easily adjusted by many shooters or by a competent gunsmith. As few as five shots on patterning paper can show where the gun shoots, and which way to adjust it for optimum pattern placement and fewer misses.

When shooting a shotgun, your eye is the rear sight. How the shotgun fits determines the "setting" of your rear sight. Patterning will show if you need to adjust your stock so the patterns hit where you want them.

How a shotgun shoot refers to how tight it patterns. Chokes and choke tubes come marked with constrictions to indicate how tight the choke should pattern. Full, modified and improved cylinder are the most common chokes, and all shotgunners should have an understanding that full choke patterns tighter than modified and modified patterns tighter than improved cylinder. There are two ways choke is usually determined. The first is to physically measure the inside constriction of the choke and compare it to a standardized table. The second is to fire through the choke and determine the percentage of hits in a 30-inch circle at 40 yards (25 yards for "skeet" chokes or .410-bore shotguns). For the most part, the choke marking on factory guns reflects the physical measurement of the choke, and does not necessarily reflect the actual pattern percentage. That percentage can be determined only by firing on patterning paper. Patterning by percentage may show that the "choke" varies from one brand of shell to another and from one shot size to another.