Why Your Shotgun Throws the Wrong Pattern

By Randy Wakeman


As much talk as there has always been about a "best" or "optimum" pattern from your shotgun, it doesn't exist. It never can exist, in a practical sense. Every shot we take is necessarily a compromise whether in the field or at clays. It just has to be, as what is arbitrarily defined as a "better" pattern remains just a matter of opinion. Better for what; and how do you define better? Anyone who recommends a choke type for you in a specific gun is necessarily going to be wrong a lot of the time.

No one means to be wrong or wants to give you bad information, not choke makers and certainly not gun manufacturers, but they have to be wrong much of the time because they do not know the exact distance to your target, your payload, your shot size, the shot type, your wad type, or the presentation of that target.

Your standard 28 gauge load of .75 oz. of #9 shot for the skeet field is about 435 pellets. The birds appear when you call for them, take a known flight path at known distances, rarely beyond 22 yards. With numbers like that, an outside observer might rightfully wonder why a 28 gauge deserves its own skeet classification, and how we could possibly ever miss? But, miss we do, and those that can go out and run the skeet field ten times in a row without fail are a rare commodity.

The largest effective pattern at five yards cannot be the most effective pattern at 20 yards. The largest effective pattern on a relatively exposed bird cannot be the largest effective pattern on a turned or edge on target, which the wind is happy to do for us. The largest effective pattern on a frozen clay bird cannot be the largest effective pattern on a warm, crumbly bird. The number of pellet hits that it takes to break a bird is inexact; a walk around the skeet field will quickly reveal a number of "lost" birds with two, three, or four pellet holes in them.

No matter how "efficient" a 28 ga. pattern is thought to be, it can only be efficient with .75 oz. of shot. Obviously, a 20 ga. gives you one third more pellets to work with, and a 12 ga. skeet load gives you fifty percent more pellets to work with. Yet we still can miss, and do.

The theory of "optimum" or best choke, best pattern, or "ideal" pattern gets far more problematic in the field. A pheasant does not hit the sky when you call for him. The distances are variable not only in length but in height. The presentation of a pheasant is also variable, as it generally is with wild birds.

Incoming dove and pass-shooting are far different applications. Even if agreement was made on a "proper" pattern at 25 yards (which hasn't happened yet), it cannot possibly be equally as "proper" at 30, 35, 40, or 45 yards. Nor would it be "proper" at 20 yards. A shot cloud is a dynamic thing, always changing as distances change.

Differences of opinion exist on what constitutes a killing pattern. An exposed, passing bird offers a far easier path to its vitals compared to a pheasant with its head down offering a raking shot. Then, of course, you might have heard about the "blowing up" of a bird, or a "stew bird." To prepare for a reasonable pattern density on an angling bird necessarily means more hits on an exposed presentation of that same bird.

John Brindle showed that the maximum effective killing pattern of 1-1/8 oz. of shot, by his standards, could not exceed twenty-one inches. Less shot mandates a smaller killing pattern, more payload offers the potential of more. If you accept the results of Brindle, George Oberfell, E. D. Lowry and so forth it will become apparent that the hoary standard of "choke" and pattern efficiency is a bit flawed: a 30 inch pattern percentage at 40 yards is not relevant at all if 21 inches of effective pattern is all that can be achieved. A 21 inch pattern percentage at the range we shoot at makes infinitely more sense. It is the vague nature of patterns that keeps George Trulock (of Trulock Choke Tubes fame) and his boys constantly shooting and patterning in order to give people what they think they want.

Most people have forgotten George G. Oberfell's seminal article that appeared in the September, 1950 American Rifleman titled simply "Shotgun Patterns." The focus was on patchiness, and remains one of the best articulated missives written on the matter.

A look at Mr. Oberfell's tabulated patchiness data shows that patterns widely from shot to shot, mandating ten shots or so to detect a 15% more efficient pattern and 25 shots to detect a 5% change either way. The pattern game quickly becomes one of probabilities and trends, not absolutes. This is very, very hard to accept for those of us trained to believe that "Modified" stamped on a barrel or choke tube means anything tangible or exact, for the opposite is true.

Old habits die very hard, but physics and probabilities have not changed. It is up to us to define what range we want our shotgun best suited for, what is a proper killing pattern to achieve that, and how much payload with which we want to work.

The 28 gauge .75 oz. load is far too much of a disadvantage for an ethical hunter to overcome at extended ranges, or for larger birds. Yet, no distinction can be made between a .75 oz. 1200 fps load producing a 65% pattern at 40 yards whether it came out of a 28, 20, 16, or 12 gauge. There is no tangible difference.

Likewise, there is no tangible difference between a 1-1/4 oz. 1200 fps load of #5 shot producing a 65% pattern at 40 yards whether a 20, 16, or a 12 gauge produced it. The probability of finding a pattern change based on gauge is there, but assuming hard shot and moderate velocities, the most credible evidence points to a 1-4 percent difference. That 1-4 percent difference in pattern thinning due to shot string on worst-case scenario long range 90 degree crossing shots (E. D. Lowry) moots the entire shot-string psychosis.

Based on general shell availability, 1 oz. from a 20, 16, and 12 ga. all have the same potential, as do 1-1/8 oz. and 1-1/4 oz. loads. Little distinction can be made between a 65% pattern efficiency derived from a 1-1/4 oz. 1200 fps load fired from a 20, 16, or 12 gauge either in lethality, range, or much of anything else, with a few caveats.

If you use cheap promo loads with soft shot and variable wadding, the 12 ga. has the probability of giving you the best results. Cheap stuff tends to work better in the larger 12 gauge.

Only Federal offers factory 1-1/4 oz. 16 ga. loads, so your options are limited. Though 20 ga. three inch shells may pattern as well as 12 gauge loads, you have a velocity limitation if that is important, and the probability is that you will need hard shot or nickel-plated shot to find high percentages, along with an extended choke tube or a choke with a long enough parallel section to handle the additional shot column length.

Again, these are only trends and probabilities. What the individual shooter must always decide is the pattern he wants, at the range he wants. It will always be a compromise, a compromise borne of probabilities and trends more than absolutes. There is of course the one "Magic Choke Tube," as mentioned here: http://www.chuckhawks.com/magic_shotgun_choke.htm It, like all the rest, is another compromise.

If you have suffered though all of this, well, I congratulate you. With all the cumulative tolerances and variations present in shotguns and shotshells, it all boils back down to the importance of patterning your own gun and deciding what compromise is the best reasonable compromise for you, your gun, and your unique application set. Though not spectacular or bombastic, reasonable selection through reasonable personal testing nets you a higher probability of satisfactory results.




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Copyright 2007 by Randy Wakeman. All rights reserved.



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