How to Properly Fit Your Shotgun
November 14, 2012
The key to good wingshooting requires two things, a consistent gun mount and a shotgun that shoots where you look. Shotguns are pointed, not aimed. If we stood on the curb and I told you to point your finger at passing vehicles, and then to point at various distances ahead of them, it would be easy. But put a gun in your hands and you begin aiming, checking the distance between your gun and the car; the simple becomes difficult.
Shooting instructor Gil Ash says, "If you watch a target or bird for over 10 feet, your brain will know where it will be for the next 10 feet." The brain is a wonderful thing, and if we allow our brain to guide the shot and not complicate it by trying to aim, wingshooting becomes fun. But the key is a gun that fits.
Any gun fitter worth his salt will tell you that a gun cannot be fitted unless you possess a good, consistent mount. Smacking the butt into your shoulder, craning your head down on the stock, and then chasing after the target is not a good mount.
A good mount begins with the flush, when the first move is to lock your eyes onto the bird. Simultaneously, the leading hand — the left hand if you are right-handed — begins moving the muzzles with the bird. Following the leading hand, the trigger hand guides the gun to the cheek and lastly into the shoulder.
During the entire process the eyes are locked onto the bird, and the gun, driven by the brain, is tracking the bird. As the gun comes into the shoulder the muzzles move ahead of the bird and the shot is taken. Much of this trusts the subconscious mind to lead the gun, which has learned through practice, and that's how it should be.
A fine wingshot with a good gun mount seems to be moving in slow motion. Why? Because his entire effort is guided by his sharp focus on the bird and totally directed to bringing the gun to the bird in a fluid manner. Develop and practice a good consistent gun mount, and you're ready for a fitting.
What It's Worth
The only way to fit a shotgun is by shooting. Some say that inserting a flashlight into the muzzle then pointing it at a target is all there is to it: If the beam of light hits the target, the gun fits you. But this does not take into account where the pattern actually strikes because of barrel flex, and how it is centered in relation to the shooter's eye and physique. It's very rough, and while perhaps not totally worthless, it's close.
Because of barrel flex, fitting for one style of shotgun won't also be accurate for another. When a double shotgun is fired the barrels attempt to open, and since they are held tightly to the breech face, they flex downward. In a repeater with its magazine tube and forend this phenomena is not pronounced, and because the barrels of an over/under form an I-beam, they flex far less than those of a side-by-side. Therefore, in general, the stock dimensions for a side-by-side will be slightly higher to compensate for barrel flex, and therefore differ from those for an over/under.
Fitting a gun requires a safe area with some means of mounting a target at or just above eye level. Many use a steel plate covered with spray paint or grease, but paper targets are easier for a do-it-yourselfer. Then, from the face of the target measure exactly 16 yards and mark the spot. Why 16 yards? Because at this distance for every inch the pattern deviates from the point of aim a one-sixteenth-inch correction to the stock is necessary. Therefore, if the center of the pattern strikes 2 inches low, the comb of the stock must be raised 1â„â‚ˆ-inch to center it.
Many feel length of pull to be the important measurement, as witnessed by numerous individuals putting the stock in the crook of their arm and reaching for the trigger to "check the fit." This, however, only proves that you have a gun, an arm and a finger. Length of pull is determined by where the head meets the stock.
As a rule, proper length of pull when the gun is mounted positions the shooter's nose an inch-and-a-half to two inches from the shooter's thumb as he grasps the wrist of the stock. Too far and the stock will be awkward to mount, too close and the nose is in jeopardy of being whacked by the thumb in recoil.
A heavily cheeked shooter will require more cast than someone with a narrow, thin face. American shotgun manufacturers largely ignore cast, and accommodate for it by lowered combs on their production stocks.
Back to the patterning board. With the 16-yard distance established and a target in place I use Birchwood Casey 3-inch orange target centers for good visibility. Shoot three shots at the same target, carefully aiming at the marked center. Be sure that the gun is mounted with the cheek firmly against the stock. This will establish a baseline, and generally will show how the stock fits. I use the tightest choke available and light target loads.
Unless there is a shooting problem, these aimed shots will normally superimpose one over the other. Carefully evaluate the target. Determine the patterns' center, then measure the distance from it to the center aiming point. From this we can make our preliminary adjustments. Deviation left to right can indicate a too-low comb and/or a cast problem. Vertical deviation from the center indicates a too-high or too-low comb.
Correcting a too-low comb is easily done using strips of leather taped to the stock with plastic electrical tape. Stock length can be adjusted by adding a slip-on recoil pad or washers inserted between the butt plate and stock. Cast and a too-high comb are more difficult to achieve without actually altering the stock, and we're not ready for that.
Perhaps one of the biggest advantages of having a stock fitting by a professional is that they will have a "try gun." A try gun has a fully articulated or adjustable stock that enables the fitter to accommodate for every possible human configuration. Most try guns are butt heavy, hence not as pleasant to shoot as a well-balanced bird gun.
Once the optimum dimensions are achieved, the fitter will transcribe them using specialized stock measuring tools to something resembling a prescription that can then be translated into corrections to an existing stock or a new one by a skilled stocker.
Once temporary corrections are made it's back to the pattern plate. It's a good idea to shoot an additional three aimed shots to verify the corrections. If all seems well, then it's time to shoot three more, this time mounting the gun and firing. I normally shoot the first three in slow motion, deliberately mounting the gun and firing, then three more mounting and firing in a quick but not rushed manner.
If a mount goes haywire, just shoot another shot and expect that one of the four superimposed patterns will be off center. Again, evaluate, see where they strike, and make further adjustments as dictated. By the way, if your tests to this point show that the gun shoots where you want it, leave the stock alone. We don't have to go butchering wood if the gun shoots where you look.
If a higher or lower comb or cast is dictated, perhaps the easiest way to correct a wooden stock is to have a skilled gunsmith install an adjustable comb. He will cut a segment from the comb, then install hardware that enables you to raise and lower the comb and move it laterally to provide cast. Some of these craftsmen visit the big skeet, trap and sporting-clay shoots throughout the summer, and most do the work overnight.
European-made shotguns are mostly stocked with cast; both cast-off for right-handed shooters, and left-handed cast-on stocks are often an option. Beretta, Benelli, Franchi, Stoeger, Winchester's Super X3 and Mossberg's 900 series make their semi-auto stocks, including the synthetics, using a system of spacers that enable adjustment for drop and cast.
While not offering precise adjustments for each individual, by using these shim kits the shooter can adjust his stock pretty close to perfect. Many manufacturers now supply recoil pads of different thickness and spacers to adjust for length of pull. Shotguns with wooden stocks can be lengthened by adding a recoil pad and spacers or by cutting the stock to shorten it. Carefully sanding down the side of the comb can create cast.
Once the stock is where it ought to be on the pattern board, then go to the skeet field and shoot some birds from low seven. Shoot with a low gun as pre-mounting defeats the process of fitting the gun. Low seven is a straightaway shot that requires that you only shoot directly at it. It will reveal much, because if the stock isn't on, you will be able to tell that you are breaking birds on one side or the other on top or bottom.
Next, shoot some incoming birds from the high house, as these birds also allow detection of imperfect fit if they are missed below or above. Even better is to shoot birds with an un-mounted gun from a high tower, as that will also reveal whether or not your stock is properly adjusted.
Stock fitting is an art, and any good fitter will tell you to shoot your stock with its temporary adjustment for several months, even a year, before making permanent changes. A conscientious fitter will often ask that you return in six months or a year to complete the fitting; sometimes with the admonition to work on establishing a consistent gun mount. With the mount stabilized, he will be able to make the final adjustments, or start over as the case may be.
Having a stock fitted takes work on the shooter's part by developing a good consistent gun mount and from that an experienced fitter can set the stock for you, and lacking a fitter, you can come close yourself. Still, once you feel you have it correct on your own, a check by an experienced fitter will pay dividends.