Patterning Shotguns with Colonel Smoothbore
By Kelsey

Posted: November 25, 2012

I want to take some time away from our discussion of shotgun types and chat a little bit about patterning shotguns. I have found that very few shotgunners ever pattern their guns. Some of you might wonder why you should pattern a “scattergun.” Well, would you mount a scope on you rifle and go hunting without sighting it in, or take an open sighted gun to the field without knowing where the point of impact is? I hope not. Patterning a shotgun is basically the same thing as sighting in a rifle or handgun.

Patterning a shotgun is a simple, somewhat time consuming, and a little bit boring. The industry standard distance for patterning is 40 yards. Pattern densities for the various choke constrictions are measured at this distance. The number of pellets that hit inside a 30 inch circle at 40 yards divided by the number of pellets in the shot charge gives us a percentage that determines choke description. Here’s a list of shot percentages inside a 30 inch circle for the corresponding choke constriction.

  • Full Choke: 70% or higher
  • Improved Modified: 65%
  • Modified: 55-60%
  • Skeet No. 2: 55-60%
  • Quarter Choke: 50%
  • Improved Cylinder: 45%
  • Skeet No. 1: 35-40%
  • Cylinder: 35-40%

For the average shooter, I recommend the following process to check the pattern of your shotgun. First you’ll need 6 sheets of paper or cardboard measuring 4’x4’. Draw a 4 to 6 inch circle in the middle of each sheet. You will be shooting one time at each sheet at 10, 30, and then 40 yards. Use a sight picture like the one shown in this post, the front bead of the shotgun pointed at the bottom of the circle. It will take a little time to shoot and then change the paper after each shot (the boring part), but when you are done you should have a pretty good idea just where the point of impact is in relation to your point of alignment.

Remember that you are looking only at a 2 dimensional picture of your pattern. But in reality, your shot string travels in 3 dimensions; length, width, and depth.  We’ll explore this 3 dimensional aspect more in my next post, and then explain what the patterns can tell you about your gun.

I’ve just received NRA instructor’s certification in both metallic and shot shell reloading. Classes will be offered early in 2013. You can check all the offerings of the Smoothbore Shooting School at

Be safe and good shooting.

Colonel Smoothbore








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