30 Inches, 40 Yards

Shotgun patterns, either on paper or steel patterning plates, are notoriously unphotogenic, and publishers often fall back on illustrations, such as this one in Gough Thomas’s Gun Book (1970). They are misleading, since they show no pellets outside the circle—and there are many!

by Terry Wieland

Patterning a shotgun is not rocket science.  It’s not even grade nine algebra.  It’s more like changing a tire and, depending on what you hope to learn from it, does not take nearly as long.

Of course there are those who make anything far more complicated than it needs to be.  The late Don Zutz, a quite well respected writer from the 1980s, was one of those.  By profession, I understand he was a science teacher, which may account for his attitude.  Anyway, in one piece explaining how to determine if your gun actually had a full choke or something less, he recommended the following course of action.

Full choke, by definition, delivers a 70 per cent pattern—that is, 70 per cent of a cartridge’s shot charge, inside a 30-inch circle, at 40 yards.  Obviously, you need to know how many pellets there are to start with.  According to the charts, an ounce of #8s consists of 410 pellets, assuming an alloy of 3 per cent antimony.  (As you can see, the caveats have already begun.)

This being the case, full choke should put 287 pellets inside that 30-inch circle.  Obviously, however, one shot is not definitive, and most knowledgeable shotgun men recommend you fire five shots and average the counts.

Ah, but not so fast, said Mr. Zutz.  Not every one-ounce load has 410 pellets.  Some might have 412, or 420; others, only 405 or 408.  What you need to do is dismantle at least five shotshells, count the pellets in each one, and average that count.  Only then do you fire five shots from the same box of shells, at five different paper patterning targets, draw the 30-inch circles, and start counting the pellet holes.

And, if your average pellet count comes to 417 instead of 410, and you count an average of 286 holes in each circle, your average is…what?  A mere 68.585131894 per cent.  To quote Mistah Kurtz, “The horror, the horror.”

By this time, the rocket scientists, statisticians, and mathematical obsessives among you may be gnashing your teeth and mentally demanding my head for such heresy.  After all, choke (and detachable choke tubes) are all-important in the modern world of ultra-sophisticated shotgunnery.  Except, I would argue, they are more a distraction than an aid, and suggest that we place entirely too much emphasis on choke, and the lack or excess thereof.

For example, something else that has always puzzled me is the fact that, to measure choke properly, you pick a spot on the patterning board to point at, fire the shot, and only after that do you pick the center point of the pattern and draw the 30-inch circle around it and start counting.

What if the center of the pattern is 15 inches low and two feet to the left of where you were pointing?  You may still count pellets and cheer at getting a 72 per cent (full and a bit) pattern, but you would have missed your intended target.

To an experienced shooter, no counting is necessary in this case, because it simply doesn’t matter.  One glance at the patterning board tells him there is something badly wrong that needs to be corrected, and it’s not the pellet count.

Imagine shooting your big-game rifle, recording a one-inch, five-shot group that was 18 inches from your aim point, and instead of adjusting your sights accordingly, you figure a small group is all you need.

Shotgun patterns have been subjects of study, controversy, and gun-club back and forth for a century and a half, but they are still largely misunderstood by the vast majority of shooters.  To confirm this, all you have to do is stand around a Skeet field on a Saturday morning and listen to the conversations.  And it’s no wonder.  In a recent (2009) edition of the Gun Digest Book of Trap and Skeet Shooting, the editor quotes one “expert” instructor as saying “choke determines the size of your pattern,” and instead of gently correcting this, later repeats it.

Well, it simply ain’t true.  Choke may help determine the density of your pattern, and even the distribution of pellets in that pattern, but it does not determine pattern size any more than gauge does, or barrel length, or the color of your eyes.  Remember, what counts is the number of pellets inside that 30-inch circle, not the breadth of the pattern itself.

In itself, this mistake is not important, but mistakes like that contribute to misconceptions about what a particular choke tube can, and cannot, do.

If you are consistently missing hard lefts on a trap field, switching choke tubes is not going to solve the problem.  If high-house eight gives you fits at Skeet, it’s not your choke.  And if bounding rabbits always escape into the bushes, guess what?

The one simple truth that every shotgunner should bear in mind is that every pattern, whether thrown from a barrel with a Full choke or Cylinder, or anything in between, always has a core pattern, running like a pipe down the center, from a few yards in front of the muzzle until the last pellet hits the ground (well, almost).  If you’re pointing the gun correctly, the bird will fall or the clay will break, regardless.

Don’t believe me?  Next time you shoot trap, try a round with the Cylinder choke tube instead of IM or LF.  The shots where you’re dead on?  Turned to dust.  And where you’re not?  You know the answer.

Gray’s shooting editor, Terry Wieland, feels he has complete mastery of every way in which you can miss a target with a shotgun.  He learned long ago not to blame the choke.