Shot Gun Stock Fitting Terms and How To's





NYECOGunsmith

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If The Shotgun Don’t Fit………You Ain’t Gonna Hit,,,,,,,,,,anything with it that is............

Over the last week I have had 4 different people call asking for information about shotgun stocks, how to measure them, make them fit, etc.

So, here ya go.

First off we need to look at the LOP,,, “Length Of Pull”. This is the distance from the center of the recoil pad or buttstock to the front face of the trigger.

On the human side, it roughly corresponds to the distance from the inside crook of your elbow to the first pad on the tip of your index finger.

Most factory stocks today will come with about a 14 to 14.5” length of pull, which will fit a wide variety of folks wearing a wide variety of clothing weights / thicknesses. Youths and women's stocks come with anywhere from 12-1/4" to 13-1/2" LOP.

The general rule of thumb for setting length of pull on a shotgun is to go with whatever is most comfortable for the shooter, with some fine tuning tossed in.

If the stock is too short, the shooter may find his or her face too far forward on the “Comb” of the stock.

The Comb, by the way, is that ridgeline that runs along the top of the stock.

It may be either a straight comb, a sloping comb, or a Monte Carlo (raised cheek piece) comb. Monte Carlo combs are generally either straight, or semi circular, dropping off at the front and rear of the raised section.

But no matter which it is, if your face is too far forward on it, you will run the risk of smacking your nose with your thumb upon firing and it may cause you to shoot high if the gun has a sloping comb and is also too short for you.

Your eye is the rear sight on a shotgun, and getting it to the right place, and the same place every time you mount the gun is what fitting a shotgun stock is all about.

Doesn’t matter so much if it then shoots high, low, or point of aim, the shooter can learn to adapt to that if they don’t want to change the stock further, but the gun has to come to the same cheek weld, shoulder weld, and position of both hands every time you mount it.

No repeatability means a much lower success rate at busting birds or clays.
Repeatability plus the right fit results in more birds busted and less felt recoil.

If the stock is too long will often cause a shooter to shot low, and give them trouble when it comes to a smooth mount of the gun to their shoulder.

Drop

The drop of the stock is measured at three points.
There is the drop at the comb, the drop at the heel, and the drop at the toe.

All three are measured the same way.

A straight edge, like a aluminum or steel yard stick is placed on top of the barrel of a single barrel shotgun, pump gun, semi-auto or over/under, so that it is in line with the central axis of the bore.

On a double barrel (side by side) it is placed down the center of the rib between the two barrels.

In other words, you are measuring from the sighting plane of the gun, downward.

From the bottom edge of the straight edge you measure down to the comb at it’s leading edge, to the heel (the heel is the upper “point” of the butt of the stock) or toe (the toe is the lower point of the butt of the stock, and is below the heel) to determine the drop at whichever of the three points you are interested in.

Most field guns today (Remington 870 Wing Master or Express, BPS, Benellie, Winchester, etc. ) come with about 1.5” (1- ½”) of drop at the comb.

Generally speaking, this is the point where your cheekbone makes contact with the stock.

And since this is where your cheek makes contact, it determines the position of your eye with relation to the top of the barrel(s), the “sighting plane”.

So a higher comb, that’s one with less drop, will cause the gun to shoot higher for you than would one with a lower comb (more drop) since in positions your eye higher or lower in relation to the muzzle.

Since our eye is the rear sight, and since whichever way you move the rear sight so goes the impact point of the gun, you can see how this can be manipulated to give you the point of aim / point of impact relationship you want.

Some folks (Trap shooters for example) like to have the bird just above the bead when they slap the trigger, so they might want less of a drop at the comb, say, something on the order of 1.355 “ (1- 3/8”).

They want to see all the target as they shoot at it in other words.

You might wonder why going from a drop of 1.5 inches, which would put the pattern of a field gun at the 50-50 point (that’s where 50% of the pattern is above the bead or point of aim, and 50% is below it) to one of 1 -3/8” (less drop, sometimes called a “high comb”) would result in such a dramatic change from a comb height change of only 0.125” (1/8”). Its because over the distance being fired, say, 40 yards on the trap field, it would move the pattern to a 75% -25% point, where 75% of the pattern ends up being above the point of aim, and 25% below it.
This is because that little 1/8” change will shift the pattern roughly 8-10 inches at a distance of 40 yards, 40 Yards being a common distance that trap birds are fired on and / or broken at.

Drop can be increased by installing shims at the receiver/ stock junction, or by sanding or planning away wood on the stock at the point where you want to alter the drop. Or it can be done by installing an adjustable cheek piece or recoil pad, like the ones from Morgan, Graco, Sierra Precision, Tubbs, Meadow Industries,etc.

Lessening the drop can be done with shims as well, or by building up the comb or point you want raised, or again by installing an adjustable cheek piece or recoil pad, like the ones from Morgan, Graco, Sierra Precision, Tubbs, Meadow Industries, etc.

Pitch

Pitch is angle at which the buttstock meets your shoulder. A quick way to measure pitch is to stand the EMPTY / UNLOADED gun against a wall with the top surface of the gun’s receiver against the wall and the butt of the stock flat on the floor.

If the receiver and the top of the barrel ( or the vent rib if it has one) are making full length contact with the wall, the gun has zero or neutral pitch.

If the barrel leans out away from the wall, then you have negative or “down” pitch.
This is the pitch preferred by most shooters. A negative pitch from the factory will run between 2” and 2.5” of distance showing up between the top of the barrel and the wall when you stand it there as described above.

Rarely if ever will you find a shotgun, especially one with a factory stock, that will have positive pitch. That’s where the barrel touches the wall as you lean it there , before the receiver touches the wall.

Pitch determines how the gun recoils towards your shoulder.

If the pitch is wrong for you, the gun will flip muzzle up or muzzle down upon firing.
If the pitch is correct, it will recoil more or less straight back into your shoulder.

Pitch can be adjusted with shims at the stock / receiver junction, or by replacing the stock with one cut with a different angle, etc.

Cast


Cast comes in three flavors.

There is cast at the toe, also called the “Cant” of the stock.

Most shotgun stocks have a buttpad that runs straight up and down. That’s zero or neutral cast at the toe, or zero or neutral cant.

This works fine for lots of folks.

But, if the pocket that is formed when you raise your arms to mount the gun has an angle to it, or the shooter has a heavy chest (fat, or heavily developed pectoral muscles, or a large bust) the mount will “drag” and slow the mount down, and hinder it being the same time after time.

And we want the buttstock to end up in the right spot in that pocket so that the recoil doesn’t hurt and induce a flinch.

So we can cast or cant the toe at an angle to compensate for this. All that means is we angle it in the proper direction to get the mount back to being smooth and repeatable and to make sure that the gun comes to our face in the same spot every time and is level.

Cast also comes in “On” and “Off” modes.

Cast on or off is referring to the bending the stock over it’s length from the junction of the stock and receiver to the buttpad.

This is done to bring the shooter’s eye, the one that is supposed to be in line with the sight plane and bead, actually in line with that point.

For a right handed shooter, a stock is “Cast Off”. That is, it is bend slightly into the shape of a backward letter “C” . The amount of bending varies by shooter and generally runs between 1/8” and a ½”, although I have had to bend a few a good deal more than that for folks who were really over weight and had heavy jowls/cheeks. The most I have ever bent one was 1 inch, that was back in the 60’s before adjustable cheek pieces and buttpads became readily available.

The bend offsets the buttpad from the receiver so that the shooter’s cheek moves further to the right and brings the center of his or her right eye into line with the midline of the bead and sight plane.

This is done by steaming the stock by the way and bending it in a custom built fixture, then leaving it to set of a couple of days. It can be touchy to do and not have the stock split if you are trying to put in a lot of cast.

It can also be done, in small amounts, by shaving the cheek piece with a convex spoke shave.

And it can be done by installing an adjustable recoil pad / buttplate, like the ones from Morgan, Graco, Sierra Precision, Tubbs, Meadow Industries, etc.

Cast off is just the left hander’s version of cast on. The stock gets shifted to the left, so that from the receiver to the buttpad it forms the letter “C” so to speak.


Grips

Some folks like a straight grip on a shotgun, some like a pistol grip, some like a pistol grip with a palm swell.

In this context, a pistol grip is NOT like you find on a Mossberg Model 500 Cruiser.
It’s just a dropped down portion of the stock between the junction of the receiver and stock, and the comb.

This is purely a matter of personal preference which one you like, but whichever one it is, when your hand slides up the stock towards the trigger, the grip area should feel like you are putting on a well fitted glove, or grabbing an old tool handle that really fits your hand well.

A poor (to your hand) fitting grip can cause you to not get a proper cheek and shoulder weld on the mount, and can cause you to smack your nose with your thumb or back of your palm when the gun discharges.

All in all, a properly fitted shotgun stock goes a long way to increasing the number of hits you make on aerial / moving targets.

But even more than that, it goes a long way to reducing felt recoil.
And you can do more with a stock to reduce felt recoil after you get it to fit you properly.

You can add weight to it.

Putting a Dead Mule® recoil reducer in the stock’s mounting bolt hole, or one of any of the other brands out there, or even something as simple as pouring that hole full of #9 lead bird shot, will help soak up the recoil.

Some of you have heard me say (and one or two have seen me do it) that I frequently shoot 1,000 ounce and an eighth loads of 12 gauge in a day while shooting any of the various games.

I wouldn’t / couldn’t do that with a 5-1/4 pound ultra light weight shotgun.
But with my 9 pound Cynergy, it’s a breeze. The stock fits me perfectly, and the gun weighs enough that it soaks up the recoil.

Some have commented on my speed at mounting and swinging the gun. That came from the first 10,000 or so rounds through it, where I added 2 pounds of #9 lead shot to the bolt hole in the stock. Flipping that 11+ pound gun to my shoulder the first 250 times wore me out that day.

But over successive days, the muscles built up. After about 10K rounds I took the shot out. Felt recoil went up, but not much, the gun still weighs 9 pounds after all, but it felt so much lighter that I was able to move it much faster.
Kind of like training with 16 ounce gloves, then stepping into the ring on fight night with 7 ounce gloves on. Your hands are going to move faster with the lighter weight in them.
Same thing applies to the shotgun.

Now once or twice a year I refill the stock with the shot and shoot it that way for a few weeks. Helps to keep the muscles in shape and get me ready for any meets I may be going to.

If you have a well fitting gun and it’s recoil is tolerable to you, but it’s still slapping you in the cheek , until you learn to mount it properly and the same each time, adding some weight to the muzzle will help with this, if that’s possible.

It can be tough to do with an over and under, or side by side, but it’s easy with a pump or semi auto, you can buy inserts for the mag tube that will add up to a pound. And if that changes the balance so that it is no longer to your liking, add the same amount of weight into the buttstock.

Felt recoil will go down and so will the muzzle flip and cheek slap, and you can concentrate on getting the mount right and busting birds.


That’s about it for the basics of a shotgun stock.

Explaining how to fit and adjust them would take up a lot more space.
It’s not rocket science, but it’s also not something you want to try for yourself (generall speaking) on your one and only shotgun stock.

If you have a spare stock, or buy an old, used one from someone who has upgraded to a aftermarket synthetic stock, by all means, give it a go.

Changing the LOP is easy to do, with some masking tape, a marker, carpentry square and a table saw. It can be done with a hand saw if you have a good eye and steady hand.

Installing a recoil pad (new or replacement) is easily done in the home shop / garage with simple hand tools. They tend to come with very complete instructions on how to do it these days.

Altering the pitch or drop or cast gets a bit more complicated if you are going to try it with any method other than adding shims, an adjustable cheek piece or buttpad, that you might want to practice several times on a scrap stock before attempting on your shooting stock.

And of course nearly any alteration to a stock will require you to refinish it to bring it back to looking good after the work is done, but that’s easy work, right?

Any questions, you know where to find me.