Summertime means shotgun season: range time, league shoots, and competitions. To shoot our best we need to make sure that our guns properly fit.
First off, choose the shotgun that best matches your anticipated style of shooting. As you look through Beretta's catalog, you'll see over-and-under, side-by-side, and semi-automatic shotguns to cover everything from upland hunting to clay target shooting, to waterfowl hunting.
Also see: Shotgun Tips: Learning From Your Misses
Once you've chosen the right shotgun, you need to make sure that it fits you properly. With a shotgun, your eye is the "rear sight" so it must be positioned perfectly every time you mount it, or you won't get repeatable accuracy. When you get your Beretta home and pull it out of the box, you'll find shims and instructions inside the box. These parts allow you to adjust the stock position so that it fits you properly. You can also find replacement stocks with different fitting options. While gun fitting is best done by a qualified professional, you may reside in a market where you have to do this yourself. If this is the case, there are some key points that you need to assess before you get started.
First of all, you need to practice and become consistent with your mount. The key to a perfect gun fit is to develop a proper and consistent mount time after time. To learn this skill, you can attend a shotgun shooting class and have an instructor teach you the correct sequence. Once you learn the correct technique, the best way to become consistent is to practice frequently until you mount the shotgun in exactly the same position each and every time. Adjustments to the fit of your shotgun will be meaningless if you mount the gun differently each time.
Length of Pull
Once you've got your mount down, you need to look at the length of pull on your shotgun. Begin with an unloaded gun, and for safety purposes, you may have a friend assist in supporting it so you can focus on fitting.
With the shotgun shouldered, observe the top of the comb and how far your nose is from the rear of your trigger hand. That distance should be approximately the same as the width of two of your fingers or one to one and a half inches. Use your support hand and put it over the top of the stock to check the distance.
If your firing hand is too close to your nose, you need to add shims or an extended butt pad. If you're too far away, you need to trim down the stock. Take care in cutting as you can always take the stock length off, but you cannot add it back on. If you haven't trimmed a stock before, I recommend taking it to a professional.
The comb is the top portion of the stock where you place your cheek. With the gun mounted, observe how far the stock drops below the bore line. With a proper comb height fit, you should be looking straight down the flat rib on top of the barrel when you mount the gun.
When you shoulder your gun, the rib should be virtually unseen. That means your eye is neither above nor below the line of the rib. If your gun has a center bead, it and the front bead should be perfectly aligned. If the front bead is above the rib or center bead, it means your comb needs to be dropped. Conversely, if the front bead is below the rib or center bead, the comb needs to be raised.
A drill you can do to recognize the need of comb height adjustment is to look at a target in the distance and then mount your gun quickly in its direction. If you have to drop or raise your head to get a flat line of sight down the rib, you need to make adjustments to the comb height.
Before you tear down the gun and start adding shims, you'll also want to check the cast.
The cast is the side to side angle of the stock in relation to the barrel. A typical angle for a right-handed shooter is called "cast-on" whereas that of a left-handed shooter is "cast-off."
With your shotgun still shouldered, observe the cast. If the front bead is to the right or left of the rib, it means you need to add shims to get the proper cast with the stock of your gun. As with comb height, you want to make sure the rib is perfectly aligned side to side when you mount the gun. If it's not, your going to shoot consistently right or left of your target.
Once you've determined whether you need to adjust your length of pull, comb height, and cast, you can follow the instructions in the Beretta user manual on how to remove the stock and add the included shims. Most shims mount between the receiver and the stock and are reversible. Depending on the orientation of the shim, you can obtain multiple fit adjustments using the same shim. Once you place a shim, repeat the comb and cast fit checks to be sure you're on the right track.