What is the proper way to measure length of pull? I've always used shotguns as bought from the store. Now that I'm trying skeet shooting I thought it would be a good idea to fit one of my shotguns to me.

The proper way to fit a shotgun is to find someone with a "try gun".There are more dimensions than just length of pull to measure. The try gun measures them all.A typical factory stock doesn't come close to fitting me so mine are modified or made from scratch. My beretta O/U was made by Orvis in Vermont if that's convenient to you.They fit you with a try gun then make a very nice stock of american walnut.Since the shotgun is pointed rather than aimed fit is much more important.

LOP is measured from the center of the trigger to the rear edge of the butt centered vertically. Most people use between 13 1/2 and about 14 1/4 inches unless they are very short or very tall.
I tend to like a shorter length of pull, just long enough so that when the gun is fired with heavy loads it doesn't jamb your thumb into your nose. This translates into about 1 1/2 to 2 inches clearance between the rear of your thumb and your nose with the gun mounted normally. Some target shooters like longer LOPs but this inhibits fast gun mounting for hunting. As I said, I don't like longer LOPs for anything, but that is a personal preference.

It is a good idea, if you are a serious shooter to have 2 recoil pads fitted, one longer for summer use, and one shorter for when heavier clothes such as sweaters, coats, or hunting parkas are required. Usually about 1/4 inch difference is enough. So use a 3/4 or 1 inch pad in summer and one a 1/4 inch thinner in winter.

Fitted stocks are nice, but after about 150 years of trying, the average American shotgun stock is pretty close for most people for hunting use, again IF you are not unusually short, fat, tall or thin.

If you are going to try an adjustment in LOP, go with Mete's advice. Find someone who has a "try gun", and see what works best for you. When you adjust LOP, you will also find that it alters the drop required, as well as cast and balance. So, even though just lengthening the pull may work, it will likely alter other important factors.

The unfortunate thing about factory stocks is that they only fit the mythical "normal" or "average" person. Whoever came up with 14 1/4" LOP must have been about 5'10" and 160lbs. Do you know anybody who fits that dimension? If you listen to 20/20 or Dateline you find out that almost all Americans don't fit that mold!

LOP can dramatically reduce felt recoil and the natural pointability of the gun. It can also improve the time it takes to mount the gun since it does not have to be "pulled" back into the shoulder when you mount it. Many people feel that a longer LOP will slow you down. This is not the case. A proper LOP will naturally seat the butt of the gun to your shoulder and require little additional movement. Unfortunately, most people learn the feel of a gun that is too short and they alter their gun mounting to accomodate it. By learning to properly mount the gun with a proper LOP will help dramatically.

If you don't think it is important, look at those people who compete in International Skeet and clays. They are not allowed to mount the gun until the rock is seen. However, many use guns that have LOPs in excess of 15". And, that rock is moving FAST in international skeet.

Just be careful, when I went to get my first gun fitted, all of a sudden, I wanted prettier wood....

Turkeyshooter,
The previous posters have given you a pretty good summary of LOP. Determining what LOP is correct for you, can be a little confusing. The statement that with the gun mounted, the back of your thumb should be 1 1/2 to 2 inches in front of your glasses is pretty much on target. Also on target is the reference that changing LOP can also change comb height, and other important dimensions.

As an avid Skeet shooter, I have been down the gun fit road many times. It is my personal opinion that one of the finest additions to a shotgun, is the Grayco adjustable butt pad, with integral LOP adjustment.

This pad will let you tweek the L0P in very small increments, thereby letting you get it just right for your personal build. It also will let you adjust the pad in any direction, up, down, left, or right. This is all the adjustment most people really need to get a proper fit. Myself, I have to have a good bit of cast off, (1/2 inch or so), in order to get my eye centered over the barrel correctly. I accomplish this by bending the stock. Once the stock is bent, I am able to then correct the fit by adjusting the butt plate as necessary. As an aside, in cold weather, when you have on heavy clothing, it only takes a minute to shorten the LOP to allow for the extra clothing.

The only thing this doesn't address is the pitch angle. This is a dimention that needs to be determined before the adjustable butt plate is installed, because it can be corrected at the same time when they cut the stock to fit the adjustable butt plate.

Custom stocks can be made to perfectly fit you, but they are quite expensive. Most people don't opt for these, for that reason. Occasionally, due to a persons particular build, an adjustable comb can be a great help also. This lets you adjust the comb up or dowm as well as left or right. This in many cases will eliminate having to bend a stock to get proper eye/rib/barrel alignment. Also for those who need a high comb, that capability is there also.

This may sound confusing, but it really isn't. the fact of the matter is, that no one will shoot an ill fitting shotgun well. So do whatever is necessary, to get your gun to fit correctly. That's the key to good shotgunning.

Regards DLM