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M40a1 build guide

Re: M40a1 build guide

All my M40A1 stuff is in KC right now so I don't have anything to look at to measure the length involved here. I know that my HTG was cut for M40A1 bottom metal per the spec sheet I received from McMillan, there is a vertical groove cut at the rear of the magazine well opening in the stock that will allow the screw to fit. 6-32 sounds about right to me, this screw should be a bit shorter than the Remington ADL screw that would be in it's place on a stock rifle. The hole for the forward trigger guard screw on the M40A1 is going to be located in the small space left in front of the latch for the floorplate after the trigger guard gets trimmed to fit the stock. I think that since the floorplate will cover this screw it is necessary to use a flat head screw counter sunk into this hole. YMMV with the little details, I am certain that even in the RTE/PWS shop things would change over time to some degree or another depending on availability of parts and such.
 
Re: M40a1 build guide

This info was posted on 10-22-07 by Parga.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Parga</div><div class="ubbcode-body">hey just for a quick update, I'm finally getting around to working on my stock and the threaded insert I have in my stock for the front triggerguard screw is a 4-40 and not a 6-32. Didn't know if that mattered to anyone but I thought I'd pass it on. </div></div>


I know that my HTG is a new stock and not a USMC return, mine only has a groove cut into the area behind the magazine box which would allow a screw to fit. I might have a photo somewhere I can post if I can find it.
 
Re: M40a1 build guide

Here is the photo...
DSC_4119.jpg


If there is a threaded insert that is to fit into this area I have not
seen a description in detail about this, but this would be good information to be had here.
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Turk</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DebosDave</div><div class="ubbcode-body">

My stock has some type of threads for the front trigger guard screw. The screw that I have is only about 1/2" long or something, it will not reach the action by any stretch. I can take a picture of this tomorrow if need be, but I doubt any return stocks have a hole that will allow the front trigger guard screw to go all the way through...

Dave </div></div>
Wrong!</div></div>

Perhaps you were a little aggressive on your stance concerning my information? Or maybe you thought we were talking about something else? Or maybe I have a different return stock than everyone else? Whatever the case, here are pictures of what I am speaking:

Front trigger guard hole, clearly threaded metal inside:
dpzr47.jpg


Didn't measure just now, but would still estimate close to 1/2" long:
j7wxlv.jpg


Here is the top, no screw hole coming all the way through, couldn't possibly thread anything into the action at this spot:
dlp5wk.jpg


Screw fits like a glove, like it belongs there:
2lcpf5u.jpg
 
Re: M40a1 build guide

Dave,
Same thing here, hmmm, guess we have something different?
Chad
 
Re: M40a1 build guide

Excellent info! Thanks for taking the time to post the photos. I wonder what GAP will do with mine? I suppose if the magazine box is tack welded on each side at the rear it could interfere with the threaded hole in the action unless there is something I am not thinking about?
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wilshire1412</div><div class="ubbcode-body">Excellent info! Thanks for taking the time to post the photos. I wonder what GAP will do with mine? I suppose if the magazine box is tack welded on each side at the rear it could interfere with the threaded hole in the action unless there is something I am not thinking about? </div></div>
It won't interfere
 
Re: M40a1 build guide

Wow! Thanks alot for the info guys - especially to you Dave for posting the pics. The new production stock I have looks pretty much like yours with regards to the bottom metal inlet. Guess I'll have to have my smith install the threaded insert when it finally comes down to having the rifle built...

Cheers,
Hernan
 
Re: M40a1 build guide

On the smear I got it looks like that screw got pulled out as there is a chunk missing where it used to be.
 
Re: M40a1 build guide

She arrived today! I knew GAP would do her right putting her together for me..... But I am speechless! Off to the range in the morning for the break-in... I will get some photos and post em for you guys!
 
Re: M40a1 build guide

Don't know what type of threaded insert the original return stocks have in them, but I'm seriously looking at the possibility of having a brass insert installed into my stock. I was looking around on Ebay and found some threaded brass inserts (I think people use them for airplane models) that are cheap as chips. They are specifically made for softer materials - like wood, plastics, etc... I guess they're used as anchor points when securing (via machine screws) motors to wooden airplane bodies, etc... They come in both 6-32 and 4-40, so whatever the official machine screw size for the spec builds is, both sizes are available. This might be an option for those that don't have a return stock or for those like Sheldon who's return stock might need a little TLC... Hope this isn't a little "off topic" as I know this thread is more geared towards providing info on spec builds - however I figure given the seemingly obscure info on the actual method used for securing the machine screw into the stock, this would be a viable and sound method...

Hernan
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: konabully</div><div class="ubbcode-body">
P3150007.JPG
</div></div>

Is it weird that I saw this pic and immediately smelled Rapid-Tap?

I think I've spent too long putting holes in things.
 
Re: M40a1 build guide

Hey guys, long time lurker...

I just spoke to my Armorer today and my build should be starting in the next two weeks. It is being overseen by a friend and former CF Armorer who has a lot of M40a1 knowledge. The build will be absolutely religious in markings and construction. Some of the parts will be a bit different in specifications but not appearance. I have gathered the following.

USMC M40a1 Return stock # 1716
GAP replacement bottom metal
TBA Unertl type 1" base/ring set
Mike Rock M40 profile 5R barrel
MRT sling, but I will be using a Les TAM sling with the USMC logo and receiver serial number.
The centre piece of the build is a Remington receiver serial number <span style="font-weight: bold">32062x</span>...originally a .243, this was the hardest piece to find and I nearly caved in and picked up a 5 digit instead...glad I held out. Scope will of course be a MST-100 as soon a Jeff gives me the call it is done...serial matching the rifles of course...the funny thing about this build is that I have never seen any of the parts as I had them shipped directly to my builder. Patience has definitely been tested on this one.
crazy.gif
 
Re: M40a1 build guide

In our Platoon we had guns with Schneider, Krieger, BlackStar, Shilen, and Hart barrels. This was in the late '90s. I do remember the Schneider barrel had over 7,000 rounds logged and it was still a hammer.

It's funny to think we only cleaned them with CLP(BreakFree) and a Otis Cleaning kit. We did get a couple guns re-barreled while I was there and they came to us with 5 or six rounds logged in the books...not much of a break-in...lol.

We weren't allowed to use any copper solvent...not even Hoppes #9...although we did keep a bottle handy to open up for the fumes...gotta have the #9 whiff in the air...lol

--KJ
 
Re: M40a1 build guide

Interesting article... Homer has Hathcock's scope and is trying to find out why the back half of the scope was refinished. Any ideas on that?
 
Re: M40a1 build guide

I posted in the WTB/WTT section, I am looking for a USO M40A1 scope mount to complete my return stock build. I have a 6 digit factory clip slotted action with split sear and just bought the last MST-100 advertised on the Hide, now if I could just find the correct scope mount, I am good to go. Please PM me if you have one you can let go.

Mods, if this is in the wrong place, please move or delete.

Thanks

 
Re: M40a1 build guide

Question. When the Marines initially built the M40A1 with the Unertl scopes what brand base and rings did they use?
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 81STFACP</div><div class="ubbcode-body">Question. When the Marines initially built the M40A1 with the Unertl scopes what brand base and rings did they use? </div></div>
According to information I have from the Senich book "One Round War:USMC Scout-Snipers in Vietnam" the first M40A1 rifles that were fitted with the Unertl retained the Redfield 40X base that was used with the Accurange scope. I think there was a reference in the book with the claim that once the larger diameter barrel of the A1 was fitted they had to switch from low rings to medium rings. This was done in order for the objective end of the Redfield scope to clear the larger diameter barrel, nothing was changed with the base/ring combo to fit the Unertl as far as I can tell. So if you are trying to do an early M40A1 build it would still be accurate to spec with the early Redfield base and then medium height bottom screw rings. Finding the right Redfield base will probably be as difficult as finding an Unertl A1 base, one of the members doing a build here did have some originals but they are/were pricey. IBA does make a mount that is close, and available in 1" rings and 0 MOA that might work.
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wilshire1412</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 81STFACP</div><div class="ubbcode-body">Question. When the Marines initially built the M40A1 with the Unertl scopes what brand base and rings did they use? </div></div>
According to information I have from the Senich book "One Round War:USMC Scout-Snipers in Vietnam" the first M40A1 rifles that were fitted with the Unertl retained the Redfield 40X base that was used with the Accurange scope. I think there was a reference in the book with the claim that once the larger diameter barrel of the A1 was fitted they had to switch from low rings to medium rings. This was done in order for the objective end of the Redfield scope to clear the larger diameter barrel, nothing was changed with the base/ring combo to fit the Unertl as far as I can tell. So if you are trying to do an early M40A1 build it would still be accurate to spec with the early Redfield base and then medium height bottom screw rings. Finding the right Redfield base will probably be as difficult as finding an Unertl A1 base, one of the members doing a build here did have some originals but they are/were pricey. IBA does make a mount that is close, and available in 1" rings and 0 MOA that might work. </div></div>

Wilshire,

Thank you for taking your time to answer. In my 6 digit receiver that I hunt with is a Redfield base with the windage screw in the rear. Is the correct base for the build the double dovetail only?

Thanks again.
 
Re: M40a1 build guide

The Redfield base used on the M40 was a COTS item at the time, Commercial Off The Shelf. As far as the information I have seen the early base was designed for the 40x target rifles and these might have even had a certain amount of angle built in to help with LR shooting. There is a difference in the rear bridge height on a six digit 700 receiver vs. a post 1974 production 700 receiver. The early receiver is shorter at the rear bridge so if you have a newer Redfield base you will likely need to do a shim and bed job to get it to fit correctly. All of the Redfield bases used regardless of when are of the same type, one piece with the dovetailed ring in the front and the windage adjustment at the rear of the base. The Unertl mount did away with the windage adjustment with two fixed rings, soldered in place as far as I know. If you are trying to just get a scope on your rifle then I would not really sweat the details over the Redfield base that you have, just get it to fit correctly and go. The early 40x marked base is a rarity, these are the ones with the square ends. I am sure that the RTE in Quantico did replace the old bases from time to time with new units that had the rounded ends prior to the availability of the Unertl unit.
 
Re: M40a1 build guide

Thanks again.

The mount on mine is the correct one for the 6 digit receiver, I also have a newer base and when I test fit it the 6 digit receiver there is indeed a gap. With your input I will just use mine, thanks for all the information.

Do the ring screws have to come up from the bottom to be correct?
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 81STFACP</div><div class="ubbcode-body">



Do the ring screws have to come up from the bottom to be correct? </div></div>
Yes, for the MST-100 using the Redfield base and rings the ring screws install from the underside.
 
Re: M40a1 build guide

Ughhh, I feel like a little kid being told I have to wait for my birthday for my present when I know what I got already! except I dunno when my birthday is...
crazy.gif
 
Re: M40a1 build guide

I have a question I have been wondering about for awhile. I have done research behind this and cant find the answer. I know that on the M40 the scope mount itself was given the serial number of the scope. Now was this continued with the M40a1. Does anyone have pics to confirm or deny that they did the same thing to the M40a1. I have not seen this and was just wondering if they continued this or not. Any light on the subject would be appreciated. Thanks in advance.
 
Re: M40a1 build guide

The original M40 base and scope were electropenciled with the rifle SN. To my knowledge this practice was not continued on the M40a1's.
 
Re: M40a1 build guide

This is a long post! I am looking for a M40A1 build complete. TBA or GA with USO scope. Does anyone know who is selling one?
 
Re: M40a1 build guide

I'm just getting one in from GAP.

It has been nearly a year since I placed the order. Once I get it, it's not going anywhere for a LONG time.

I may be wrong but I'd imagine most guys who've gone through a similar process or have spent their time getting all the correct bits together are probably going to feel the same?

Good luck with the search though!
 
Re: M40a1 build guide

I have wanted one of these ever since I about 15 and 1st seen them in pictures. Once I get mine, It's never leaving my hands until I pass away! Hopefully I have a son who will get it...
 
Re: M40a1 build guide

Working on 4 M40A1's this weekend. I have three trued and barreled up working on #4 this evening. 3 are early 6 digits, one is a late model reciever. All but one are in return stocks.

Nomad was down last weekend, we bedded his earlier built M40A1 barreled action into his recently found return stock. #1325. this was the rifle he acctuly carried in the Corps. A member here had it and traded me for one I had.


Here is a Picture of todays work so far.

Some of you may recognize your stuff.

366988420.jpg
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: A10XRIFLE</div><div class="ubbcode-body">Working on 4 M40A1's this weekend. I have three trued and barreled up working on #4 this evening. 3 are early 6 digits, one is a late model reciever. All but one are in return stocks.

Nomad was down last weekend, we bedded his earlier built M40A1 barreled action into his recently found return stock. #1325. this was the rifle he acctuly carried in the Corps. A member here had it and traded me for one I had.


Here is a Picture of todays work so far.

Some of you may recognize your stuff.

366988420.jpg


</div></div>

That forest camo stock in the middle looks familiar....?!!
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: A10XRIFLE</div><div class="ubbcode-body">Working on 4 M40A1's this weekend. I have three trued and barreled up working on #4 this evening. 3 are early 6 digits, one is a late model reciever. All but one are in return stocks.

Nomad was down last weekend, we bedded his earlier built M40A1 barreled action into his recently found return stock. #1325. this was the rifle he acctuly carried in the Corps. A member here had it and traded me for one I had.


Here is a Picture of todays work so far.

Some of you may recognize your stuff.

366988420.jpg


</div></div>

They look sweeet !! Ahhh, We need more pics !
grin.gif


mine is the top one !
 
Re: M40a1 build guide

Does the scope sit high on the M40 A1? I am going to buy a clone. The scope looks to sit very high on the gun. I would think that the scope should just clear the barrel.
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: terryg</div><div class="ubbcode-body">Does the scope sit high on the M40 A1? I am going to buy a clone. The scope looks to sit very high on the gun. I would think that the scope should just clear the barrel. </div></div>

The scope on the A1 cannot sit any lower. The base and ring set were designed to mount the scope as low as possible. It just about touches the barrel. Just surf around and look at some pics. The so-called A1's you might see with an optics rail don't count, They are not a true A1.
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: terryg</div><div class="ubbcode-body">Does the scope sit high on the M40 A1?</div></div>

It's pretty close. The problem is that the comb on the A1/HTG stock is too low for most shooters. We solve this problem by taping foam from an iso-mat to the stock then covering it with moleskin. This way the Sniper builds the stock to his face resulting in a perfect cheekweld.

MarineSniper_Spotter.jpg


Here is a pic yanked off of Google.
 
Re: M40a1 build guide

I have a couple of questions hope someone is kind enough to help me out.

First. I know that the M40a1 was painted black oxide. Now if you have a blued receiver how hard would it be to strip off the blue and get it ready to be painted in black oxide? Would this do any damage to the reciever at all?

Second. The stamps on the rifle that mark the last 4 of SN and RTE-P, what size of stamp was used? I have tried to look this info up with no sucess.

Third. I know that the action screws are 1/4x28 socket. What are the lenghts that would fit for the M40a1?

 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: A10XRIFLE</div><div class="ubbcode-body">

366988420.jpg


</div></div>

OK.. That was the nastiest tease I was ever given !
laugh.gif



Gotta Luv it !
 
Re: M40a1 build guide

It's not really referred to as paint! Bead blast it and it won't do any damage. Original M40A1's the barrel wasn't pluged for the BO! Make sure you plug the barrel before blasting though!
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sgt Henry</div><div class="ubbcode-body">Hey is it possible, or even Legal to stamp U.S. above the serial #. Like an original?
I found a digit action </div></div>

Oops I meant I found a 6 digit action from the 60's
 
Re: M40a1 build guide

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sgt Henry</div><div class="ubbcode-body">Hey is it possible, or even Legal to stamp U.S. above the serial #. Like an original?
I found a digit action </div></div>

If you look closely at the photos that George has posted directly above you can see my action, it is the one in the middle. It did not have the U.S. stamp when I sent it in, it is done by GA Precision when you request a spec build M40A1. The early 6 digit actions that went to the Marine Corps were marked this way, the later actions that were procured as replacements are reportedly without the U.S. stamp above the number. This is legal to do as it is in the end a replica rifle.
 
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