The name on your choke tube may be deceiving. Seeing the pattern is what counts.
As a result there is a renewed interest in shotgun choke tubes. The main reason for the interest is the versatility choke tubes offer.
There are definite advantages to using one gun for a variety of tasks. While the “one gun” idea has merit, it can be downright frustrating if the shot is not performing as you anticipated when it reaches the target.
This is amplified when the same gun is fired at targets that vary from snipe to turkey. What commonly plays out is that the shotgun owner is not hitting a certain type of target as often as they think they ought to, so they immediately want to have something on the gun altered.
Well-meaning shooters know they want to change their shot patterns but they go about addressing the issue the long way. Many alterations will affect the pattern of the pellets including lengthening of forcing cones, over-boring, back-boring or polishing chambers. Any of those modifications will change the shot pattern, but why not start at the beginning?
Choke is the difference of nominal bore diameter of the barrel compared to the diameter constriction at the choke. The purpose of choke is to impart resistance on the shot pellets so they stay in a certain configuration throughout their flight, slowly spreading apart as they go. While the concept is simple, there are many variables including the hardness of the pellets, type of wadding, velocity and pellet size.
First thing’s first
The first thing you must realize about choke, and particularly shotgun choke tubes is that what you see is not always what you get. Just because a certain brand of choke tube proclaims to be “modified” for instance, do not count on that to be an accurate reflection of what you see when you review your shot patterns. The only way to really know what your choke tubes are doing is to measure the patterns.
Without getting into a lot of details, the most common choke designations of improved cylinder, modified and full are roughly equivalent to .010-inch constriction each, incrementally.
It is commonly expected that those choke throw patterns of 55, 65 and 75 percent respectively. This means that at 40 yards from the muzzle, the corresponding percentage of the total number of pellets will fall within a 30-inch circle.
So what do you do when your Modified choke throws patterns that are more or less than 65 percent? If the answer was always to get the forcing cones polished, or have the barrel back-bored many gunsmiths salaries would go up significantly!
The name game
The answer is to forget the “name game” and change the choke tube. The “name game” includes the designation that was given to that choke tube as well as who manufactured it.
The first thing to do is determine if you want to increase or decrease the amount of pellets in a 30-inch circle at 40 yards, depending on what you are trying to accomplish. Then some experimentation is in order. You’ll have to shoot several patterns, each with different choke tubes to see if there is a change in the pattern density. Logic dictates that if you want a more open pattern than Modified, you should try an Improved Modified choke. However, don’t be afraid to think outside the box.
A recent client tried this experiment and determined that the Full choke included with her shotgun actually patterned five to seven percent less dense than the Modified choke. I know your Dad told you Full choke was too tight for chukar hunting, but the proof is in the pattern. It doesn’t matter what the choke says it is if it does not do what you expect it to do.
Other posts to read
In another glaring example, a target shooter told me he wished his skeet choke throw patterns that were more even. On the patterning board, the percentage of shot in the 30-inch circle was consistent with the “skeet” designation, but the pattern was very spotty and uneven.
Using a choke that was more or less constrictive did not solve the problem, as the spread of the pellets in diameter was good with skeet choke, but the pattern was just not even. The owner purchased an after-market choke tube marked “skeet,” installed it in his gun and fired some patterns. Even though this was the same designation of skeet choke like the choke tube that came with the gun, the patterns were full and even.
In spite of the two choke tubes being named the same, the after-market choke tube produced pattern closer to the owners expectations.
There is no doubt choke tubes add versatility to any shotgun. The trick is to forget the names on the tubes and just review the patterns to determine what is best for your needs.