Shotgun Patterns

Dear Technoid,

Can you briefly describe the different shot patterns that the various shotgun chokes make?


Dear Marshall,

Describe BRIEFLY?! That’s like asking Picasso to paint on a postcard! Describe, yes. Briefly, no. You gotta remember, the Technoid gets paid by the word. Yeah, right.

Believe it or not, there is no hard and fast rule as to exactly what pattern a certain choke is supposed to print. You’d think after all these years there would be some sort of agreement, but there isn’t.

The only thing that everyone agrees on is the order in which the chokes go from most open to tightest. Well, most people agree. There is a lot a name changing going on today. Generally, the following is true:

Starting with the most open chokes and going to the tightest the order is:- Cylinder bore, skeet (skeet 1), improved cylinder, light modified (skeet 2), modified, improved modified, full, extra full.

Today’s screw choke makers have attempted to invent new choke names to fill in every .005″ constriction so that they can sell more chokes. Thus we have names like “Light Full” and “Turkey 1” etc.

As to the pattens attributed to each choke, I’m just going to chicken out and not even try to make sense of it all. Every manufacturer and country has their own idea of what an Improved Cylinder or Full means. I’m referring to a chart in an old Black’s “Wing and Clay” handbook. They show their interpretation of choke performance at all the yardages, but usually chokes are measured at 40 yards. Here’s what Black’s has for the choke patterns at 40 yards:

Cylinder Bore: 40%
Skeet 1: 50%
Improved Cylinder: 55%
Modified: 60%
Improved Modified: 65%
Full: 70%

These numbers are as good as any, but just remember that shells from the same box can easily vary 5% either way during a test. Also, different types and brands of shells will pattern differently in the same gun. It’s not at all unusual for larger shot to pattern tighter than smaller shot. You could have a gun which shot Improved Cylinder with #9s and Modified with #5s without changing the choke.

Don’t think that you can determine choke performance strictly by points of constriction. You can’t. Overbore barrels have changed all that. In my experience SOME brands of overbore guns need much less constriction to produce a given density than some brands of standard bore guns. This occurs mostly at the more open end of the choke spectrum and becomes more equal as the chokes tighten. Still, it exists. Screw choke makers love to sell chokes in every .005″ designation and they have to put a “name” on each one of those constrictions. Don’t take that as Gospel. A choke designation isn’t what is stamped on the barrel or tube. It is the PERFORMANCE of the choke/shell combination. There can be a big difference.

I keep saying this until I am blue in the face (most of you do have color monitors, don’t you?)- the ONLY way to tell what you are getting in the way of performance from a particular shell in your particular gun is to PATTERN it! You have to count the pellets in the actual shell (do not use the pellet charts) and then count the pellets in a 30″ circle at 40 yards. Repeat at least three times, five is better. Ain’t no other way. None. If you don’t do that, you are just whistling in the dark.

One thing that most people don’t realize is how little difference each gradation of choke makes in the real world. People will fuss and fudget over whether to use Improved Cylinder or Modified on a certain 30 yard shot. According to Black’s charts, the difference is patterns of 35″ or 32″. Looking at it another way, the spread of an Improved Cylinder pattern and a Modified pattern at the SAME at 30 yards for the IC and 33 yards for the Mod. Is your depth perception good enough to judge the difference in distance between 30 and 33 yards on an airborne target? This is angels on the head of a pin stuff!

I love changing chokes because I view it as a form of exercise and helpful in working off the quantities of Jolt Cola (Twice the sugar! Twice the caffeine!) and Twinkies I am required to consume as your Technoidal leader. But it’s really just exercise. There are only three real shotgunning distances: close, normal and far. There may be specialty situations for turkey hunters or snipe hunters, but close, normal and far will cover 98% of most shotgunners needs.

According to Ed Lowrey’s excellent pattern program, the ideal pattern percentage is 77% at the target. I won’t get into why that is so right now, but I do favor his rationale that a 77% pattern in a 30″ circle provides the largest possible effective fringe. If this is so (using Black’s numbers), then Cylinder bore is optimized at about 21 yards, IC at 30, Mod at 32.5, and Full at about 37. There are a ton of other variables, but these numbers are pretty good. With these numbers, you would have a choke for each 10 yards if you packed a Cylinder Bore, IC and a Full. This might not be what you’d expect, but it you take Black’s numbers, there it is.

So, that’s the long version. You expected less?

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error. Never in doubt.)

This entry was posted in Shotgun related and tagged . Bookmark the permalink.

1 Response to Shotgun Patterns

  1. jon bastable says:

    Good message, Bruce! Thanks!



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