Other guys will have to help you out with your questions, but here is a ton of information on the exact dimensions of the original circa 1966 USMC M40 wood stocks. Use the information below when modifying your new reproduction USMC M40 wood stocks. This is the only place you will ever find this information, this info isn't in any reference books or in other websites/forums. It took me forever to measure the original USMC M40 stocks in my collection and create the measurement chart below, but it was 100% worth the effort! Please let me know if you have any questions. I created all of the information below, so I should be able to help with anything related to it. Just keep measuring your stock as you're working on it, and keep comparing it to the measurements on my chart below (use the mean/average column, not information on an individual stock).
Please keep in mind that this is as accurate and repeatable with each original USMC M40 stock as I could possibly make it. I've done an enormous amount of first-hand research with the entire M40 series of sniper rifles, all of which is has resulted in completely new information for the collector/historian community. M40 stock research like this has never been done before, this is all new information that isn't in any reference book.
If you're finishing a wood stock for your M40 clone build, please use the information I've provided below. Compare my measurements with the measurements from your stock and see how well they match up. The closer that your stock's measurements are to what I have listed in my chart below, the closer your stock will be to the original USMC M40 stocks.
The first two stocks on the chart (#3 and #14) are named after the rack numbers that were painted or stamped onto each of these stocks. The next four stocks on the chart are named after the last 4 digits of the original M40 serial number that was stamped on the bottom of the grip. If anyone needs information about the number stamps used on the bottom of the stock's grip, I can take measurements from the stamped numbers and post that information (clone builders might want to replicate these numbers on their stocks using the last 4 digits of their rifle's receiver serial number). The last stock on the list didn't have any identifying marks, so it's named after it's lack of numbers.
The 7 stocks are all in a row across the top of the chart. The 28 areas of measurement (of which only 27 are used) are all in a column down the chart. The A to Z letters in the chart correspond to the A to Z letters in the list below this paragraph. The list below tells you what measurement each letter represents. Since the list below isn't descriptive and concise enough on it's own, I also included photographs of an original USMC M40 stock with the A to Z measurements drawn onto the stock in the photos. Each line on the stock in the photos has a letter next to it, that letter can be matched up to it's counterpart on the descriptive list. All of this information is probably extremely obvious to you guys, but I still wanted to document everything in case some people had any questions.
One last note, in the photos below, you'll see 2 photos of the M40 stock's forend. This is not the same photo/information erroneously posted a second time, each of the 2 stock forend photos contains a different set of measurements. So, please look closely at them! Let me know if you guys have any questions about these M40 stock measurements, I'll do my best to answer them.
All measurements below and in the chart are in inches.
A. Length from the front of the recoil lug to the tip of the forend
B. Length from the tip of the forend to the center of the front sling swivel
C. Height of the stock at the tip of the forend (bottom of the stock to bottom of the barrel channel)
D. Height of the stock at the tip of the forend (right before it starts to taper off)
E. Height of the stock at the front sling swivel
F. Height of the stock midway on the forend (4 inches from the front of the recoil lug)
G. Height of the stock at the front of the recoil lug
H. Width of the stock at the tip of the forend (right before it starts to taper off)
I. Width of the stock at the front sling swivel
J. Width of the stock midway on the forend (4 inches from the front of the recoil lug)
K. Width of the stock at the front of the recoil lug
L. Width of the barrel channel at the tip of the forend (right before it starts to taper off)
M. Width of the barrel channel at the front sling swivel
N. Width of the barrel channel midway on the forend (4 inches from the front of the recoil lug)
O. Width of the barrel channel at the front of the recoil lug
P. Height of grip
Q. Width of grip
R. Circumference of the grip
S. Grip protrusion below the stock
T. Length of thumb cut on the cheek piece
U. Length of cheek piece
V. Height of cheek piece
W. Width of cheek piece
X. Height of butt
Y. Width of butt
Z. Length from end of the butt of the center of the rear sling swivel
OAL – Stock overall length (without buttplate)
Arc – The arc of the grip (I never got around to measuring this area of the stock, so there isn't any arc information recorded on the chart)
Yellow highlight = bedding material throws off the measurements
Yes, I still have all the information I ever posted on the M40 Forum, nothing of mine is lost.
Look at my post in this thread on page 3 (Post 125). I've posted a ton of M40 stock information on this forum over the years, so please let me know if this stuff helps or if you need more information.
https://www.snipershide.com/shooting/threads/m40-stock.6989158/page-3
