based on personal practice with the rifles I own. I have no experience
with fine English doubles, specially fitted stocks, highfalutin safari guns
that sell for $32,000, etc…
If any of you have special experience in this regard, please leave a comment.
Running a bolt action rifle efficiently and effectively involves bringing a number of actions and elements into harmony. You must bring the rifle quickly to the shoulder. You must get the head into a position that places the eye properly in relation to the scope or sights. You must be able to actuate the trigger without disrupting the alignment of the sights. When all this occurs, you must then work the bolt, which in my opinion should be done without breaking the cheekweld. Also, again in my opinion, you should be able to do all of the above from both the strong and weak sides (ambidextrous operation).
All of the necessary components mentioned above place competing demands for the proper length of pull. It’s like putting together a 3D puzzle. If you change one thing, everything else is affected.
Length of pull is defined as the distance from the trigger to the rifle butt. Most of us buy a gun and use it as-is. Most rifles tend to come from the factory with a length of pull in the 13.25” to 13.75” range. My Sako has a 14.25” LOP.
I’m not sure if a “perfect” length of pull exists other than a design built from the ground up for that specific person with a specific person in mind, or purely by an unlikely coincidence. The requirements for perfection of length of pull will change if the rifle is to be used in more than one position. Perhaps this is what confounds the rifle shooter who is able to use different positions. Unlike a trap or skeet shooter, or maybe someone on Safari, the one “perfect” fit may not exist.
One of the most important things that is affected by LOP is eye relief. It’s absolutely necessary that your eye ends up in the right spot when you shoulder the rifle. You should see a clear sight picture with edge to edge clarity. This is not as easy as it sounds unless, as stated above, you only shoot from one position. What works from a bipod in prone will not work the same way if you shoot with a sling in prone. Your eye will be farther away with the bipod. In a seated position with the sling, your eye will likely be as close or closer than in prone with the sling. In offhand your eye will be farther back, maybe as far as farther than bipod prone. Kneeling will bring you just a bit closer than offhand.
-Generally improvised support positions would fall in here somewhere
-Carbine style offhand
-Rice Paddy Prone
-Open Leg Sitting
-Crossed Ankle Sitting
-Unsupported prone with sling
-Crossed Leg Sitting
I find that from offhand to open leg sitting I can find the proper eye relief. If I work a bit, I can get it in crossed ankle sitting Urban prone is just a mess, as it works better with 1x sights like the EoTech and Aimpoint. With the up close positions like prone with sling or the seated positions, in which I’m so close to the ocular as to make correct eye relief impossible, I try to get the shaded area to be equal around the edge of the ocular lens. I just try to avoid crossed leg sitting altogether (there must be other, more fun ways to draw blood than from getting slammed in the forehead).
Eye relief is not just a length of pull issue. It can usually be adjusted somewhat in how the scope is mounted, although this is limited by scope design, ring height, location of the base(s) on the rifle. What would also be nice is if the scope had a forgiving range of usable eye relief. If you have $4000 to spend on glass, I hear that the Hensholdt scopes are great in terms of “eyebox” flexibility. Whether this pertains to eye relief specifically, I don’t know.
The Leupold scope on my Sako has an eye relief that changes depending on magnification. It gets longer with low magnification and vice versa. I’m not sure if this is by design or not. I have gotten used to it and generally think that it works well. Look at the list, and you’ll notice that with a few exceptions, the positions with closer eye relief are generally the ones that offer more precision. It would ultimately be nicer if the eye relief was consistent throughout the magnification range, yet offer at least the same amount of variation that my Leupold changes from 3.5-10x. More on length of pull and eye relief later.
Another, and in my opinion, more relevant and direct result of length of pull is the ability to cycle the bolt without breaking cheekweld. This is an area in which I think the Sako’s long LOP has been an asset. My action is made to work with a 30-06 length cartridge. I have never been in a shooting position that necessitated moving my head to dodge the bolt. I have been close enough for the bolt to touch my face when cycling, but not for it to be painful, but I have a really, really fat face (now you know why I black it out). I don’t know if I could reduce the LOP and still make this claim.
In the wonderful Norwegian rifle competitions, the shooters with the Sauer STR rifles chambered in 6.5×55 have to move their heads to dodge the bolt. They are able to do this consistently and quickly enough to get multiple successive hits on a head size target at 250 meters at a rate of fire of approximately a round per second (not including the time it takes to change mags). I don’t know if this is purely a function of LOP, because their sighting system and bolt technique will also place requirements on the rifle setup (these things will bring them closer to the receiver). What I am saying by bringing up the Norwegians is that if you have to move your head, do what they do. Make the movement very small, very quick, and very consistent.
Length of pull is often brought up in the context of how naturally and quickly the rifle can be shouldered. A common guideline is that if the butt is placed against the bicep with the stock and forearm running parallel, the correct LOP would place the finger comfortably on the trigger. After a bit of experimentation, I think that this guideline is probably sound and represents a good starting point. That measurement for me indicates a good “starting point” of 13.5”. Since I’m used to the 14.25” LOP, 13.5” feels short from the snapshot without any “re-indoctrination” time, although I’m sure I could get used to it. I tried a rifle with a 13.0” LOP that’s known for its naturally pointing characteristics, and it felt ridiculously short. I think that within a range, you can get used to a rifle and become quite good without a “perfect custom fit”.
Another piece of the LOP puzzle is how it affects your ability to reach the bolt knob. I think that this is the reason that most rifles come with the 13.5ish inch LOP. It can just be hard for me to reach the knob in positions like prone with sling. This is why I came up with the alternate bolt technique that I wrote about here. I could only reach the knob with my fingertips in those positions. The Norwegians, on the other hand, keep their bolts gripped by their thumb and forefinger throughout the firing cycle in prone, and they appear to sling up tight. Then again, they have to dodge the bolt, which I am not willing to do.