Before continuing with this column, I suggest you review last week’s at: http://www.montanaoutdoor.com/2018/04/shotgun-patterning-colonel-smoothbore/
Here are a few ways we can fill the “holes” in our shotgun patterns. For the sake of brevity and simplicity, we’ll just consider 12 gauge loads, but the same principles hold true for the smaller gauges.
If you have a gun with interchangeable chokes, you can start with a constriction change. If you are using steel or other non-toxic shot, I suggest that you try a more open choke. As an example, go from a modified to a light modified or improved cylinder. This change will help eliminate the “blowing” of the pattern when the non-malleable shot is overly compressed as it passes through the choke. If you are using a lead load with a heavy shot charge (1 ¼ ounce or more) and large shot size (4 or larger) the same process will likely lead to fuller, more even patterns. If you are using a light load (1 1/8 ounce or less) try a choke with more constriction. For example go from a modified to an improved modified or even a full choke. This procedure is especially effective if you are using smaller shot sizes, like 8’s and 9’s.
If you gun has a fixed choke, then you will probably have to change your chosen load. First, try the same payload (e.g. 1 1/8 ounce) but with a different muzzle velocity. For example go from a load with a MV of 1120 f/s to one of 1200 f/s MV or vice versa. If that doesn’t work go with a lighter payload, say 1 ounce instead of 1 1/8. Often times a small change in shot size can make a big difference in achieving good patterns (e.g. size 4 to size 6). Often a smaller shot size will result in better patterns. As I have stated in past posts, I use size 6 shot in either 1 or 1 1/8 ounce loads for all my upland hunting. That’s about 50 years of great patterns and 50 years of mighty tasty table fare; it really works.
Now that we have all these pieces of paper with hundreds of holes in them, what do they tell us? Here are some final thoughts on shotgun patterning.
First, as long as your eye is aligned with the bead(s) and directly down the barrel rib, your patterns at 30 and 40 yards should be split 50/50 left and right. If the pattern center is off an inch or two, don’t be too concerned. If the pattern is off center by several inches or more, you’ve probably got an alignment problem. I suggest mounting your gun in front of a mirror and check to be sure your eye’s pupil is directly in line with the bead(s) and the rib. If not, adjust your mount to achieve this alignment. Your eyes and head should be as level as possible, not tilted in any direction. If you cannot get your gun aligned properly, consult an experienced shooting coach or instructor. They can probably correct your mount if your gun fits you fairly well. If your gun fits you poorly, they can recommend a stock fitter that hopefully can adjust your stock to get you a good gun fit.
Now let’s compare the point of alignment (POA) with the point of impact (POI). If you are shooting a field shotgun, I’ll wait till later to discuss target shotgun patterns; you should have a 50/50 or 60/40 shot distribution. By that, I mean that at the POI, 50 or 60 % of the shot should hit above the POA. If your pattern is say 40/60 or even 30/70, where the POI is below the POA, simply raising the comb of your stock should raise the POI. If your gun has an adjustable comb, raise it. If your gun has a fixed comb, there are devises you can attach to it. Redi-comb has different thickness layers of padding that fit in a sleeve that wraps around the stock. Another really simple way to raise a comb is to add layers of moleskin to the stock until the desired fit is achieved. Both methods can be altered or easily removed if necessary.
Patterning your shotgun will tell you where your POI is in relation to your POA. Having a gun that “shoots where you are looking” will make you a more efficient and effective shotgunner. If you have any questions about this topic or others related to firearms, just send them to firstname.lastname@example.org.
Be safe and good shooting.