Gun Fitting – By Don Currie

Whether shooting clay targets or upland bird, the shotgunner must achieve eye-barrel alignment naturally, without visually verifying alignment of the eye with the “sights.”  (If you don’t believe me, read The Churchill Method) If mounted properly, a well fitting shotgun will shoot where the shooter is looking as he engages a moving target; and because of the need to sharp visual focus on the target without regard to eye-barrel alignment, a well fitting gun is essential to higher performance in shotgunning.

Gun Fit is the degree to which the dominant eye properly aligns with the rib when the gun is naturally mounted to the cheek and while the shooter is focused exclusively on the target.  A mounted shotgun is said to “fit” when the shooter’s eye is centered on the rib and positioned just over the rib (like a marble on a table). But since all of us are physically unique, how do we equip the 5’6″ 120 lb. female shooter and the 6’2″ 200 lb. male shooter with a gun that ”fits”?  The answer is, with the help of a gun fitter and a “bespoke” or fitted shotgun. First off, shotgun manufacturers generally design shotguns to fit a male shooter who wears a size 40 jacket, weighs 180 lbs., is 5’10” tall and has average facial dimensions.  The more that your body deviates from these generic specifications, the more likely it is that some intervention will be required to get your eye centered above the rib of your shotgun.   Replacing the existing stock of a shotgun with a custom stock can be pretty pricey: anywhere between $2,500 and $4,500 depending on the quality of the wood blank.  However, there are a number of less expensive alternatives available, which we will discuss later.  First, lets look at the basic dimensional variables of a shotgun and how they affect the point-of-impact of the shot pattern.  The most important elements of gun fit are length of pull, drop at comb, cast and pitch.  There are many more dimensions, such as palm swell and toe out, but we will confine our conversation here to the basic elements.

Length of Pull is the distance measured between the front/center of the trigger and the center of the leading edge of the butt pad.  A gun that is too long for you will be uncomfortable to shoot, difficult to control and deliver more recoil.  A gun that is too short may cause your face to ride up too close to your trigger hand. Your shotgun has the proper length of pull when the knuckle at the base of the thumb on the trigger hand is about 1” to 1-1/2” in front of your nose. Females and youth shooters are especially likely to run into problems with length of pull because they tend to be smaller in stature.  Another complication of length of pull arises because most stocks have a comb that is higher at the “peak” and lower at the “heal”.  As a result, changing the length of pull of your gun will also impact the height of your eye over the rib when fully mounted.  The closer your head gets to the peak of the comb, the higher your eye will be positioned over the rib.

Cast refers to the deviation of the comb away from the centerline of the gun.  For a shotgun with no cast, the centerline of the comb is lined up exactly with the center of the rib.  If a gun has cast, the centerline of the comb of the stock is off-center compared to the centerline of the rib.  In order for a shotgun to fit a shooter properly, the stock normally needs some amount of cast away from the face, known as “cast off”.  If a gun has “cast-on,” the stock is slightly off center toward the shooter’s face.  (These terms vary slightly between the US and European markets)  How much cast is needed is determined primarily by the shooter’s facial structure.

Drop at comb is the vertical distance between the top of the comb and a straight, imaginary line along the center of the rib extending over the top of the comb back to the heal of the butt.  This measurement is usually taken in two places:  at the peak of the comb and at the heel.  The drop at comb is typically greater at the heal than at the peak, unless you are dealing with the rare parallel comb.  If the drop at comb is too slight, your eye will come to rest at a point too far above the rib.  If the drop at comb is too much, your dominant eye will dip down below the rib when the gun is fully mounted, occluding your view of the target.  We tend to see this often in female and youth shooters and others with a high cheekbone and narrow facial features.  Again, the goal is to have your eye centered on the rib and positioned just over the rib, like a marble on a table.

Pitch is the angle of the butt pad in relationship to the rib.  A gun is said to have “no pitch” if the angle of the butt pad is perfectly perpendicular (90 degrees) to the rib of the shotgun.  A gun is said to have “pitch” if the toe of the butt is angled in and away from the shooter (positive pitch) or angled toward the shooter (negative pitch).  The goal is to have as much surface contact between the butt pad and the shoulder as possible when the gun is properly and fully mounted.  Most guns are manufactured with a 4 degree pitch but females and weight lifters, for example, tend to need a bit more.  Shooting a gun with excessive pitch will be uncomfortable to shoot and the recoil of the gun when discharged may cause downward barrel jump.  Conversely, a gun with too little pitch will result in excessive upward muzzle jump and be equally uncomfortable for the shooter.

Tools of the Trade There are a couple of tools used by expert gun fitters to establish the ideal fit dimensions for an individual shooter.  A “try-gun” is a shotgun that is highly reengineered with a metal  “knuckle” and other metal hinges that allow the gun fitter to make minute and complex adjustments in order to “dial in” the gun to the individual shooter.  Once the ideal “point-of-impact” is achieved on the patterning board, precise measurements are taken and recorded in the event a custom gun is contemplated.  A patterning board is the second and most common tool used to by gun fitters to verify point-of impact and gun fit.  There are a host of different designs for a patterning board but the most ideal is a 40” x 40” steel plate with a small hole in the center.  By coating the patterning board with spray paint or industrial grease, a gun fitter can see the shape of the shot pattern, identify the center of the pattern and adjust the gun measurements accordingly. While there are gun fitters

Point-of-Impact To many, reading and understanding the shot pattern on a patterning board, and relating it to gun fit, can be a bit confusing.  Just think of your eye and the center of the shot pattern as a straight line with a hinge at the center bead of your shotgun.  If the eye it too high over the rib (drop at comb is not sufficient), the point of impact will be high of center and you will tend to shoot over some targets. If, from the shooter’s perspective, the eye is too far to the right of the rib (too much cast off), the shot pattern will be to the right of center on the patterning board.  If the eye is too far left (not enough cast), the shooter will shoot left of center.  An exception to the “hinge rule” comes into play when the shooter’s eye is too low on the gun (drop at comb is too much).  In this instance, the barrel is likely blocking the shooter’s view of the target and 

Less expensive alternatives So what if you already have a gun, but suspect that it doesn’t fit?  You are thinking of visiting a gun fitter, but are afraid of what you might hear and would rather spend your money on a family vacation? I’m not trying to talk myself out of custom gun sales here, but there are a number of very viable alternatives to a custom stock or a new custom gun that you may want to consider.  Adjusting the gun you already have is always less expensive than the alternatives but before you get started down this road, beware of who you turn to for “expert” assistance.  Not every gunsmith is experienced with working on shotgun stocks or adjusting shotguns to shooters.  Most gun fitters (me included) have reliable, expert stock makers and craftsmen that they routinely deal with and in whom they have great confidence.  Turn to the experts that specialize in fine shotguns before throwing your gun up on your garage workbench or letting the gunsmith at your local pawn shot put his mitts on your Italian over/under.

How much is it going to hurt, Doc? If your shotgun is too long, your gun fitter will shorten the stock and grind and install a new butt pad.   If your stock is too short, he will likely grind and install a new butt pad and use spacers to increase the length of the gun.  I am not a fan of Kickeez pads because they are made of a very “sticky” rubber and tend to bind up in the vest or clothing during the mount.   I strongly recommend the Pachmyer Sporting Clays butt pad for this reason.  It is perhaps $30 more expensive but well worth the difference. A new butt pad and length of pull adjustment with spacers will run you between $100 and $150.  If your gun needs a pitch adjustment, this can be addressed at the same time as the new butt pad is installed at little or no additional cost. If a change in cast or drop at comb is called for, an adjustable comb is a great alternative to a custom stock. Installation of a good quality light metal adjustable comb will set you back about $300 – $400 (installed) but will allow you to adjust the height of the comb as well as the cast.  The nice thing about an adjustable comb is that it can be fine-tuned at any time.  Changes in your mount, or a 10-pound increase in your weight over the holidays, may change your fit and point of impact.  With a custom stock, this is an expensive problem.  With an adjustable comb, you can quickly make adjustments with an Allan wrench and you are back in business.  In a worst-case scenario, you are looking at a total of about $500 for the length of pull adjustment and adjustable comb installation. This is a whole lot cheaper than a bespoke shotgun or a new stock. One caution however: An adjustable comb will add weight to the back of your gun and therefore change the gun’s dynamics and the way it swings to the target.  This imbalance can be fixed by installing some small weights in the fore end to compensate.  For fans of automatic shotguns, the more recent models come with an assortment of shims and spacers for adjustment.  Providing your dimensions fall within the tolerances of these guns, you can save yourself the expense of a custom stock, but you would still be well served to have a gun fitter perform the fitting and adjustments.  If you haven’t yet bought a gun, buying a new one with an adjustable comb is a great move.  If you feel that you might also need a length of pull adjustment from the standard 14-3/8 to 14-5/8 industry standard, you might want to pay a bit extra and order a gun with a custom length of pull (typically under $400).

A bespoke shotgun If all else fails, you don’t like the looks of an adjustable comb or that Christmas bonus is burning a whole in your pocket, by all means, come see me (or another experienced gun fitter) for a fitting and place your custom shotgun order. It’s a lot less expensive to order a new gun with a stock customized to your personal dimensions than it is to re-stock a shotgun.  Caesar Guerin, for example, will make a custom gun to your measurements for an upcharge of only $1,200.  While you will have to wait about 60-90 days for delivery, it is better than the five to seven month wait typical of most other European manufacturers.  Blaser will actually give you a discount to help offset the cost of a custom stock if you order an F3 without wood.  If you don’t’ mind the wait, and quality is what you are after, think about a Zoli or Perazzi made to custom measurements. They are well worth the price and wait.

Bottom Line In shotgunning, your shooting eye must be properly centered over the rib of our shotgun when properly mounted or the gun simply won’t shoot where you are looking. If the dimensions of your shotgun are off a mere 1/8th of an inch at the comb, that translates to two inches of deviation in the shot pattern at 16 yards and six inches at 48 yards.  Seek the assistance of an experienced gun fitter and make sure your shotgun is shooting where you are looking.

To learn more about the type of gun fittings Don offers, click HERE.

© 2016 – Don Currie

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