Shot gun shot strings are a part of ballistics and a reference to how close the pellets stay together when they hit their target and are not a direct reference to the inside or outside design of the barrel itself. There can be confusion when researching guns online as some sites consider a shot string to be a barrel pattern.
Although they are sometimes interchangeable as references to the spread of the pellets upon impact, barrel patterns can also refer to the rifling (pattern) or bore of the inside of the shotgun barrel. For this post we’ll mainly use shot string for the explanation.
The shot string is a combination of the:
- Shape and weight of the pellets in the shell
- Amount of powder used
- Length of the barrel
- Choke tube being added to the end of the barrel
- Distance between the person firing and the target
Each of these impacts the width of your shot string differently. When you have more gun powder loaded the velocity is increased with the added propulsion keeping the pellets closer together over a longer distance.
When you add a choke tube to the end of a shotgun barrel you can fasten it tight or loose. When you use a tight choke tube it condenses the pellets as it leaves the bore, keeping a tight shot string over an even longer distance just like when you use more gun powder. And if you loosen the choke tube you can get a wider spread for a shorter distance.
You’ll want looser choke tubes for fast moving and close range game like doves and grouse that will take off in an instant. The wider spread of the pellets gives you a better chance to make an impact for fast-moving, close-range targets. The opposite is true for turkey and large game you hunt at a distance. The tighter choke will keep the pellets condensed for a longer distance giving you a more accurate pathway to your target.
Longer barrels help to tighten the pellets as they leave the bore keeping a tighter shot string as they reach their target. If the bore (the diameter of the inside of the barrel) is not sized to match the pellets, this can cause improper shot strings and excessive wear and tear on the shotgun. So make sure you match the correct gauges to prolong its life.
The shapes of the pellets inside the shotgun shell will also impact the shot string barrel pattern as some shapes are more aerodynamic than others. But don’t worry about the shape too much as most are circular at this point. The weight of the pellets for modern firearms and ammunition will likely have more of an impact.
If the weight is mixed they disperse faster creating a wider shot string. When the pellets are the same or very close in weight they can keep a tighter barrel pattern upon impact. If you notice, the distance between the person and the target keeps coming up.
As the pellets leave the shotgun barrel they start in a tight pattern. The air works against this pattern causing the pellets to spread loosening their shot string. The longer the distance between the person firing the shotgun and the target, the more opportunity for natural forces like gravity, wind, and air resistance to spread the pellets further changing the shot string before impact.
Shot strings are a reference to the way the pellets hit their target and are controlled by the length of the barrel, the amount of powder used, the distance between the person firing and the target, as well as the shape, weight, and quality of the pellets themselves. And now you know how to modify the spread of a shot string so you can hunt fast moving targets at close range, or big game and predators at a distance with more efficiency.
