Shooting TipsFebruary 2017 - BRSI Tip:
This is a long tip, because this is a very complicated topic. First and foremost, I am not a stock fitter or a stock maker. This is intended to be a guide to help my readers understand gun fit and to assess if they need a professional gun fitter.
I see enough gun fit questions from my students and on Shotgun World Forum (shotgunworld.com) that it is worth addressing it here. I have gleaned the following from my experience and from many other sources. I am not a gun fitter. Never make permanent changes to a shotgun based on this information. This information is designed to give you a starting point for a productive discussion with a qualified stock fitter. Any change you make to part of a stock will change other measurements. This interactive characteristic of gunstock measurements is why it may take more than two fitting by qualified stock maker to work it out.
Which comes first the fit or the mount? The gun is a fixed object that you cannot change without considerable effort. Your gun mount is, to a certain degree, flexible. Ideally, both should be perfect. The first step is to know what a good gun mount is, how to execute it and what it feels like. Then when you mount a gun that does not allow you to accomplish a good gun mount, you know that the gun does not fit. You now have choices-you may sacrifice your very best possible gun mount to fit yourself to a gun. Or, you may choose to have the gun modified to fit you. Sometimes the final decision is a combines both. Whatever you decide to do, it should be a fully informed decision made with the help of a qualified stock fitter. It is my hope that the following will help you with this complex process.
With an UNLOADED GUN, practice mounting into a mirror-you should be able to see your shooting eye aligned with the rib both horizontally and vertically. Depending on how you are built, the recoil pad should be in the pocket of your shoulder with the shelf of your cheekbone resting comfortably on the comb of the stock. The recoil pad should be flush against your shoulder and the barrels level and true (neither muzzle up or down and no cant to either side). There should be about 1.25 to 2 inches between the thumb of your trigger hand and your nose if the Length of Pull (LOP) is correct. Have a friend, significant other, etc. check this for you.
If the barrel is not horizontal then the pitch of the stock is not right for your shoulder. A washer or two at either the heel or toe of the stock will shim it into alignment. This is a temporary fix that must be confirmed by a stock fitter and made permanent by a qualifier stock maker.
Gun cant can be caused by either hand imparting a twisting vector into the gun mount. This can be fixed by finding a comfortable grip for both hands that removes the cant. In extreme cases it may require a stock fitter bending the stock.
The distance from your knuckle to your nose is an indicator of LOP. Being too close can be adjusted by rotating your support foot in the direction of the gun. This pulls your shooting shoulder back, effectively lengthening the gun's LOP. Shimming the recoil pad with cardboard can be used to accomplish the same result.
Gun Mount--With your head erect, look up about 45 degrees and push the gun up and away from your body. Now focus on the bead and draw the gun back toward your shooting eye. The gun will land in the pocket of our shoulder and you will be looking down the side of the gun. Maintain the head erect posture and slowly turn your head toward the gun--when your shooting eye aligns with the rib, lower your cheek onto the comb of the stock. The stock should along your upper teeth and under the cheekbone. The amount of pressure will depend on your build and the dimensions of your shotgun. A bow at the waist will bring the gun down to address the target.
Your gun mount requires proper foot position, posture, and stance in order for this process to produce usable results. Chris Batha's book, Breaking Clays, contains a very good explanation of gun mount with pictures.