Rifle stocks are seemingly simple things. They are the things you bolt all the actual gun parts to, which keeps you from holding all the actual rifle parts themselves. Why should they be so complicated then? Simple. Because theyíre the interface between the oodles of different body shapes and the oodles of different gun shapes and even more oodles of use cases.
Trying to pair a stock with a rifle canít be done without some vision of what the use case will be, or you have a good chance of ending up with a rifle that doesnít work well for its intended purpose. You can sort the things that matter into some very simple categories: Style/Form Factor, Materials, Bedding, Weight, Cost.
There are also some terms of stock construction that you should familiarize yourself with, such as: comb, heel, toe, butt, grip, fore end, cast-off/on, length of pull, and pitch. Weíll ignore some of the fine detail here and cover the broad strokes. If you want to know more, see some of the links, pictures and examples at the end of this article.
Styles are many, and sometimes itís less than obvious how to categorize what might be an element of one particular style or another, versus what is simply variation within a style. The basic style of the stock needs to be able to position your eye in line with the sights in whatever position the gun is meant to be used in, must provide a solid base to mount the action to and needs to allow recoil to be absorbed. A stock thatís just right for shooting offhand while standing will be very differently shaped than one thatís meant to be shot from a bench rest or one thatís optimized for prone shooting.
In broad categories you have combinations of the following: wide fore end, narrow fore end, flat fore end, curved fore end, short fore end, long fore end, flat comb, raised comb, rollover comb, straight grip, curved grip, pistol grip, thumbhole grip, flat butt, curved butt, one-piece, two-piece, fixed butt, collapsible butt, folding butt, and probably 50 other things Iím leaving out.
The fore end is the part generally forward of the grip. Iíve always thought that there is missing terminology here because the part of the stock the action is supported by in my view should not be considered part of the fore end. The fore end to my mind should be everything that is forward of the receiver. This would rationalize the nomenclature. Thatís an argument for another day.
Fore ends that are slender and curved on the bottom are generally more comfortable to shoot off-hand quickly. The curved profile fits the hand nicely. A flat fore end is optimal for shooting from some sort of supporting structure or device like sand bags or a bipod. Most shooters will find any corners to be less than comfortable for offhand shooting. There are notable exceptions to this rule in sports like metallic silhouette which is shot standing off-hand unsupported. Many shooters in that sport opt for a hold on the rifle that places the fore end on the finger tips with the tip of the thumb supporting the rifle closer to the magazine or trigger guard.
While the flat fore end works there, the shooters are taking a good bit of time for each shot. Hunters taking much quicker shots on average would not generally adopt such a stance or hold. A flat fore end allows for the rifle to rest evenly and flat on bags or rollers and for easy attachment of attachment systems like Anschutz rails and Picatinny rails to which gobs of nifty gadgets can be mounted.
The grip is the part your trigger hand holds. Grips vary from proceeding nearly straight back from the trigger guard to the comb (where your cheek goes) all the way to completely vertical and may or may not be part of the actual butt stock. Modern Sporting Rifles like AR/AK/FAL pattern rifles and their various kin tend toward a separate pistol grip.
Most conventional bolt action hunting rifles have a pistol grip thatís part of the main stock and which curves gently downward and rearward blending into the butt section. Lever guns like the Winchester 1894 and some versions of the Marlin 336 tend toward straight non-curved grip sections that transition abruptly into the butt section.
Generally target rifles with grips very near to vertical have some benefits in ergonomics as it allows the pull on the trigger to be more purely straight back. What is a benefit on the target range isnít likely to be the case in the wild lands on a hunt where you need more flexibility and a more general purpose pistol grip profile like the common curved or straight forms are appropriate.
Now comes the butt section. There are a lot of parts here as most of the way a stock lays out is defined by various parts of the geometry of the butt section. The butt itself as a bit of nomenclature is both the very rear section that contacts your shoulder and the stuff behind the grip. This is another area where I think weíre missing useful additional terminology but Iíll continue to avoid that discussion for now.
In the butt section will be the comb. As mentioned before thatís the bit that your cheek rests on. Its height is critical to aligning your eye with the sights in the vertical plane. If youíre not able to rest your cheek on the comb and see your sights then you need to raise or lower either the sights or the comb until you can for both your comfort and for the best results in your shooting.
A very low comb like on a Winchester 1894 is great for use with iron sights but horrible for use with a scope unless you add a cheek piece that raises your head up high enough to see through the scope. A very high cheek piece that gets your head up high enough for a scope with a large objective bell will likely prevent the use of low mounted iron sights.
At the very back of the butt there are two positions that determine a lot of the overall geometry of the rifle. That is the heel and toe. The heel is the point at the uppermost, rearmost part of the butt. The toe is the bottom most, rear most point. The angle of those two points relative to an imaginary line drawn from the heel to the tip of the fore end determines the pitch, or up/down angle of the stock. The distance vertically from the heel to the top of the comb is the drop at comb.
A large drop at comb helps raise the action of the rifle relative to the butt. This is handy for shooting from the standing position as it helps keep your head and neck straight up and down which helps with your inner ear working with your brain to sense what level is so as to not cant the rifle. Any drop at comb will increase the uncomfortable perceived effects of recoil along with making it harder to recover from recoil.
The M16 stock and most lever gun stocks come straight back from the axis of the bore to the shoulder providing a very straight path for recoil forces to travel down. Thatís fine for a light recoiling gun but might not be so great for a hard kicking rifle. Just like with a pistol, raising the bore line above the comb line will cause more muzzle rise to be experienced. Just like with a single action revolver, muzzle rise takes energy to happen and allowing it to happen can lessen perceived recoil on the shoulder.
The drop at heel versus drop at comb determines the actual distance covered by the butt plate/recoil pad/butt. Too small a difference between the drop and heel and drop at comb will make for a sharp feel to the butt under recoil.