This is my explanation of the elements of fit and their affect on recoil and gun handling.
Most obvious and easiest is length of pull. The standard is place the butt in the crook of your arm and can you wrap put your finger on the trigger properly. If you are going to be wearing a certain set of clothes put them on to make this measurement. The stock LOP is 13.5 inches but this can vary greatly among individuals. You are better off with a LOP that is a quarter inch to short than too long.
Next is comb
The straighter the barrel and action aligns with the butt stock the less felt recoil and it also lessens the muzzle rise. Thus the popularity of thee Weatherby style stock for hard hitting magnums. In other words you want the line of recoil force to be as straight back into the centre of your shoulder as you can manage.
Height. of comb and drop are dependent on how long your neck is and how high on your head your eyes are set. This actually varies a great deal from one person to another. You want a good cheek weld. If the comb is too low you will feel the comb slap you and you will not get consistent groups. if it is too high you will be pushing down too hard too see through the scope. Some comb issues can be addressed by changing the height of the rings.
Next is cant
More common on shotguns but also can be found on custom riffles. Cant is where the ttop of the comb is left or right of vertical to account for a particular shooters tendency to cant the gun left or right from vertical. The idea is to have the shooter comfortable but still have the gun straight up and down.
Finally is cast
This refers to the gun stock being bent left or right. The most extreme example would be a stock built for a right hand shooter that use their left eye for aiming. The idea of cast is to look straight down the barrel without having to crane your neck or adopt other uncomfortable positions.
For felt recoil the proper length of pull and a straight line of recoil, along with the right comb height are the most important factors.
Hope this helps.
PS Took me a while to write this and i see a bunch of others weighed in with good info in between.
This second description was provided by a long time gun maker "Leeper"
Rifle fit is usually accomplished by the most adjustable part of the equation - the shooter. Most shooters have, by long use of rifles which may or may not have fit them well, adapted to the point that they feel pretty good. This makes it a bit difficult to truly fit a rifle to the individual if such fitting is based solely on his or her physical characteristics. Many shorter riflemen tend to shoot across their body because they have had to do so in order to be comfortable with rifles which were too long for them. Women often tend to lean back too much and tilt their head to the side because they feel overbalanced by rifles which are too long and too heavy for them and by differences in their physiology.
Another problem we run into is, in rifle design, all too often, function follows form. There is some justification for this. If we look at many of today's tactical and target stocks, where it can be said that form follows function, the form is often a bit on the homely side. Homely or not, they at least fit well on the shoulder and allow for a solid cheek weld while placing the hand in a comfortable position. Still, the appearance would have to be classed in the "acquired taste" category.
If we establish what we consider to be proper form, we can then attempt to fit the rifle to the shooter who is holding it properly. When shooting offhand or from any other position, for that matter, the line of the bore should be at forty-five degrees to a line drawn across the shoulders. The head must be held so the eye is aligned with the scope. If, in the offhand position, this results in the thumb of the hand on the grip being closer than about 3/4 inch from the nose, the stock is too short. If the shooter has to stretch to get within 3/4 inch of said thumb, the stock is too long. If the shooter has to make the angle more acute (shoot across the body), the stock may be too long or the shooter's shoulder may be wide enough that he requires some cast-off to be built into the stock. If the shooter has to tilt his head to the side, some cast-off would help. If he has to push his face too tightly against the stock to achieve alignment, some cast off may help or some thinning of the comb might be necessary.
With the rifle held comfortably against the shoulder, the rifle should be level. If it is not, it may be necessary to build some cant into the butt.
All of this is just scratching the surface and shows just how complex fitting a stock could be if we were to get too carried away with it. Fortunately, we are, ourselves, very adjustable and can get away with changing only those things which are readily changed; stock length, pitch, cant, height of the line of sight, etc.
Shoot a rifle for a while and, if there is something about the fit which really bugs you, see if it can be corrected tastefully (without duct tape or plumbing repair parts).
As far as recoil is concerned, use padding when shooting from the bench. Don't let the rifle hurt you and you won't develop a flinch. Leeper
