Shotgun Fitting

Shotgun fitting is becoming a more popular custom gunsmithing service. This is a result of growing understanding among shooters that fit of the shotgun plays a major role in placing the shot where it is expected. Shooting at flying target requires pointing rather than aiming and pointing is a rapid, intuitive motion, combined with concentration on the flying target, leading it, and pulling the trigger.

In such conditions, with limited time and multiple variables, only the correct fit of the gun ensures that the impact is where the shooter intends to put it. Well, all other mistakes excluded. I would like to exactly define what the fit is but at this point it is easier to explain what it is not. Misfit means a physical inability of the shooter to line up the aiming eye with the top rib of the shotgun.

In other words, the projection of the rib-line cannot be placed into the center of the eye or can only be achieved with an awkward position of the shooter’s head, neck, and shoulders. If this is so, then either the geometry of the stock is inappropriate for the body proportions of the shooter or the way of shouldering the gun is incorrect. The "correctness" of shouldering requires explanation.

The competition for the highest scores in the shotgun shooting sports have developed a pretty standard way of shouldering the gun. There are several basic requirements: First, keep weight of the body on the front foot. Second, keep the cheekbone firm on the comb without tilting the head. Third, keep the stock firm on the height of the shoulder. Fourth, relieve unnecessary tension on the neck and shoulders. With certain practice these requirements become a second nature.

While I am not trying here to teach a shooting technique—this is a task for instructors—my goal here is to stress that fitting the gun cannot be done to any body position and requires a certain, developed consistency of shouldering. For example, to fit the gun to a sitting shooter is very different from doing the same for a standing one. Again, if the cheek is not firm on the stock and the head is not tied with the gun, then one of the major stock dimensions—drop at comb (DAC)—cannot be determined correctly.

The same goes for the other dimensions discussed below. Body position is important. This is why when fitting the gun to a beginning shooter I first spend time on achieving the shooter’s correct shouldering and body position or sort of it. Note that shouldering of the beginner will be gradually changing with shooting experience. Fitting Dimensions The major fitting dimensions of the stock geometry defining the fit are the Length Of Pull (LOP), Drop At Comb (DAC), Drop At Hill (DAH), Cast, Pitch, and Twist.

It is interesting to note that after achieving correct body position and shouldering, some shooters do not need to proceed with fitting work as the gun actually fits correctly as-is. So, what is the whole goal of fitting? Here is the exact definition as I pursue it in my practice: Fitting the gun to a shooter is a process of changing the stock geometry so that the aiming eye of the shooter can be lined up with the top rib of the shotgun, while the gun shouldered comfortable and correctly.

This puts the shooter’s eye directly over the rib, which is the only correct position. To judge the position of the shooter’s eye the gunsmith-fitter first makes sure that the gun is correctly shouldered. Then, staying in front of the shooter several feet away he looks along the rib from the muzzle side, projecting the rib-line onto the shooter’s eye. If it does not look like the shooter’s eye is directly over the rib-line after several shoulderings, the stock geometry should be changed.

Yes, procedure requires the gun to be pointed directly at the head of the fitter, so all safety precautions must be in place. It is also important that the shooter keeps his finger on the trigger as this allows assessment of the length of the palm rest on the gun with the pistol grip. This parameter is seldom changed and I do not list it in major dimensions, however, in cases of a shooter having a very small or very large palm, adjustment here is in order. The mentioned comfort of shouldering requires attention.

It is not the way of pleasing the shooter but a necessary feature of making correct shots. A very important and not widely known rule is that starting the shot with any discomfort will cause error. During the time spent concentrating on the target and pulling the trigger will let the body move to a less uncomfortable position. The recoil makes that movement unnoticed and leaves the shooter wondering why the target is still flying.

To exclude uncomfortable gun positioning, always ask the shooter to shoulder the gun from the low position having his eyes closed. With closed eyes the shooter does not intuitively force himself into lining up with the rib. After shouldering, check the correctness of the alignment and ask the shooter to open their eyes. Do this several times and watch the position of the aiming eye relative to the top rib. This exercise is the most effective in establishing the necessary steps of any needed stock modification.

The desired position of the eye is directly over the rib. Each stock dimension has its own particular role. Let’s discuss them one-by-one assuming that shouldering is correct. Note that in the past most stock modifications were done with bending via means of heat. This technique is still used but stocks on shotguns became quite bulky with a central bolt inside which makes this approach less popular. Instead, a number of fit adjusting devices have become popular and are considered here.

Length Of Pull (LOP) defines the linear position (B) of the head on the stock and position of gripping hand with the trigger finger. The rule for adjusting LOP is that the distance between the shooter’s nose and thumb knuckle is about 1". If this distance is much less or allows the nose to overlap with the knuckle, then the stock is short and the shooter will have tendency to relieve the firm contact of the stock with the shoulder or even distant the stock out of shoulder.

When this Top: The major fitting dimensions and their position on the stock. LOP, Length Of Pull. A, Drop At Comb (DAC). B, linear position of the head on the stock. C, Drop At Hill (DAH). P, Pitch. G, Central rib line. W, cast off. Q, twist. Center: Different positions of the shooter’s eye relatively to the top rib. It is important to shoulder the gun with closed eyes from the low position and open eyes after shouldering is complete.

Only position 1 is correct as this puts the shooter’s eye directly over the rib. is happening, the semi-auto shotguns fail cycling and single-trigger shotguns with inertia mechanism fail switching to a second shot. On other hand, the too long stock is always uncomfortable but is simple to adjust—just shorten the stock. To adjust LOP for a short stock, install a wooden or plastic spacer. However, a more advanced way is to use an adjustable butt plate such as the Gra Coil from Graco Corporation.

Drop At Comb (DAC) defines vertical position of the head on the stock. The standard averages around 1.5" but often needs a custom change. If DAC is too big, then the shooter has his aiming eye too low—below the rib line. If DAC is too small, the shooter has his eye too high above the rib line. The popular way of modifying the DAC is installation of an adjustable comb. In fact, the adjustable comb is quite versatile as it moves up-down and also left-right. More on that later.

Drop At Hill (DAH) defines vertical position of the stock on the shoulder. The standard is about 2.5" although this parameter greatly depends on the length of

com, adjustable buttplate. 1, the shock absorbing cylinder with coil for absorbing recoil. 2, the thread for adjusting Length Of Pull. 3, four-way adjusting sliding plate for adjusting Drop At Hill and Cast. com, ) Rectangle Comb Adjuster provides four way adjustable comb hardware. Vertical adjustments establish DAC, horizontal adjustments adjust cast on or cast off. neck and face of the shooter. Tall shooters with along neck often need DAH increased as they are trying to place the butt pad above the shoulder.

Popular devices for this change are butt plate adjusters made by 100 Straight Products, Stock Positioning Systems, and Gra- Coil-type device from Graco with an additional sliding plate. There are several kinds of these devices which have to be chosen to match the circumstances and price. Cast (angle W) defines horizontal position of the head on the stock. Some shooters with wide faces need a significant cast. The illustration here shows cast-off, which is required for right hand shooters.

It also is shown as the distance Lseen from behind the stock butt. For the lefties this angle and distance Lare called cast-on and should be by the other side of the center-line G. Note that with a four-way adjustable comb combined with a sliding buttplate, the cast-off or cast-on can be established by shifting the comb and butt-plate right or left. Pitch (angle P) defines whether the gun is for high-flying or lowflying targets.

For example, Skeet shooters require smaller or even negative pitch as the gun is mostly pointed up for the shot while Trap shooters would be better with a bigger angle Pitch as the gun is pointed at targets much lower. This parameter can be adjusted by shaping the stock butt or installing an appropriate pad. The goal of this adjustment is to provide the most complete contact of the buttpad with the shoulder during the shot.

Some pads, like the Rocker Pad shown on the next page, can be good for shooting both low and high targets. American Gunsmith Reader Services 1.

3dcartstores.com, Adjustable Plate. This allows adjustments through the pad with one wrench. As with Gra Coil, the sliding plate on this device can establish DAH and Cast, which is very convenient when LOP does not need to be changed. Bis a Trap Pad, suitable for mostly low shots. The bump on the top helps to fill the distance with the shoulder. Twist (angle Q) defines the cant of the gun. Some shooters significantly cant the gun and it may be corrected with adding more Twist and angle Qto the stock-pad.

However, the canting mostly happens not American Gunsmith Mailing List Policy Like many other publishers, we make portions of our customer list available to carefully screened companies that offer products and services we believe you may enjoy.

If you do not wish to receive these offers, and/or information, please let us know by contacting us at: American Gunsmith Opt-Out Program Norwalk, CT 06854 Please include your current mailing label. because of the butt-pad position on the shoulder, as many would think, but because the shooter is intuitively moving the rib-line closer to his eye when the cast and DAC are incorrect. Note that both 100 Straight Products plate and the Gra Coil have the ability of adjusting Q.

Conclusion This article may be a starting guide for the beginning fitter. The rest comes with experience. My goal here is to point out the role of each stock dimension in gun-fit to a shooter and also mention the most popular devices for stock modification. There are multiple publications on shotgun fitting and I would like to name two good ones: Stock Fitter’s Bible by Rollin Oswald and Gunfitting: The Quest for Perfection for Shotguns and Rifles by Michael Yardley and Paul Roberts.

I think that these books promote understanding of the gun-fit and uncover hidden reasons behind the lost targets. Finally, a brief note on try-guns. Though they are useful for establishing optimal dimensions of the stock for the particular shooter, their role is diminished by the existence of adjustable devices described earlier. These devices convert almost every gun to a try-gun anyway. AG