PrecisionRifleBlog.com A DATA-DRIVEN Approach to Precision Rifles, Optics & Gear
Related Articles
There are two types of adjustments you can make on the McMillan A5 stocks:
- Adjust Length of Pull (LOP)
- Adjust Comb (i.e. cheek piece)
Both of these adjustments are designed to provide better site acquisition, comfort, and control of your weapon. These same adjustments are common on most of McMillan tactical style stocks (A3, A4, A3-5, etc), as well as some competition and other models of stocks.
How To Adjust Length of Pull (LOP) On McMillan Stocks
If you don’t know what your length of pull should be, it’s easy to measure. Check out this article on how to measure your length of pull.
The McMillan A5 stock has a spacer system that allows you to adjust the length of pull from 13″ to 14.5″. It can be done in just a few minutes, and all you need is a 5/32 allen wrench. Start by loosening the two screws from the butt of the rifle. You don’t need to take them all the way … just loosen them a few turns.
The steps below illustrate how spacers are installed, and you can see how simple of a setup this really is.
The McMillan stock comes with 4 spacers, which appear to be two thin and two thick … but mine turned out to all have varying thicknesses. I don’t know if this was by design or a quality control issue … but either way it works. I removed the thickest spacer (0.49″), which gives me an ideal lenght of pull with the remaining 3.
After you get the proper number of spacer installed/uninstalled, just tighten up the screws back up and your done. McMillan provides enough spacers to fit the majority of shooters, but you can order additional spacers if you need a longer adjustment.
How To Adjust Comb/Cheekpiece On McMillan Stocks
The integral cheekpiece is simple to use. Just twist the single knob/dial on the righthand side of the butt, and you can slide the cheekpiece up and down (or lift it completely out of the stock, which is convenient for cleaning). Find the position you like, and just tighten down that same knob. This operation is completely toolless … it’s simple, convenient, and very quick.
Have you ever tried shining a small flashlight thru the objective lens and watching where the exit pupil focuses when the scope or rifle is laid flat on a table ? You can then have someone tell you IF that focus transition is hitting your “closed” eyelid low / centered / or high and either adjust your comb height or make a cheek weld impression in your foam cheek rest to center. I am really enjoying digging in your archives.
Festina Lentex
CRaTXn
I actually did something similar to measure the eye relief in the scope field tests I just published (see video demo below). I’ve never thought of using that to help with setting up a scope for a natural point of aim, but that makes sense.
[youtube http://www.youtube.com/watch?v=BDD2rfS28xk%5D
Oh, as an old shotgun shooter there is something missing in this stock fitting article…caste off or sanding or rasping an indentation into the stock for proper eye alignment with an erect uncanted head. Pitch and toe canting are also important for quick shots and jumped game but you can’t condense a Reader’s Digest version just to make me happy. Great articles
Somewhere Between Ignorance & Arrogance,
CRaTXn
Wow … I never thought about applying some of the same ideas of fitting a shotgun stock. I know a few guys who shoot shotguns competitively, so I’m familiar with the idea. Do you have any resources you could share with us with more detail on that topic?
The link for measuring LOP at the top of this article has been changed to
http://accurateinnovations.com/options/length-of-pull/
Thanks for the update. Got it changed.