Why doesn't a G.I. stock fit my rifle?!!! - M14 Forum

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Why doesn't a G.I. stock fit my rifle?!!!

This is a discussion on Why doesn't a G.I. stock fit my rifle?!!! within the Gus Fisher forums, part of the Gun Professionals category; Folks, this is a HUGE question amoung the semi auto M14 community. The short answer is that commercial receivers are not made to the same ...


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Old March 10th, 2009, 07:47 PM   #1
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Why doesn't a G.I. stock fit my rifle?!!!

Folks, this is a HUGE question amoung the semi auto M14 community. The short answer is that commercial receivers are not made to the same blueprint and tolerances of G.I. receivers in the bedding areas. Some are darn close and that's why some commercial receivers will fit, but other receivers are different enough that they won't fit G.I. stocks well. Making a commercial receiver to exactly the same specifications and tolerances of a G.I. receiver would mean the price of the receiver would have to be as much as Three or Four thousand dollars and almost no one would pay that much. OK, that's the short answer, now let's get into more detail.

G.I. Garand and M14 receivers were made to extremely exacting tolerances in part so wood stocks could be made in mass production and so they would all fit correctly. The Garand Collecting Community has documented the number one part on the Garand Rifle that got rejected the most for being out of tolerance was the receiver. Though the M14 receiver is much simpler to make, I suspect the same is true for it as well. This is why wood stocks from so many different manufacturers and in different time periods all fit the Garand and M14 receivers respectively so well. Ah, but there are huge differences in commercial M14 receivers and that is the problem with them fitting G.I. M14 stocks.

Some commercial receivers are enough different from G.I. spec. receivers that it is darn near impossible to have a correct ďdrop inĒ fit with a G.I. stock. SAinc especially had MAJOR differences in the way the receivers fit over the years. For a long time, they had the bottom of the receiver heel too high and they would not properly sit down and be tightened against the stock. SAinc. also made some receivers where the distance from the front to the back of the receiver legs was longer than G.I. receivers. That was OK as you could file/fit the liner to the receiver. However, SAinc also made receivers where the distance from front to back was LESS than G.I. receivers. This means those receivers will be loose in ANY G.I. stock, unless it is glass bedded to the receiver. But donít think Iím just picking on SAinc. receivers.

Armscorps and some SAinc. and other receivers were known for having a different angle of metal shoulders where the receiver comes down on top of the stock from the rear of the receiver legs to the front of the receiver. This angle was a sharper downward angle than on G.I. receivers. That could and sometimes meant it would keep the receiver too high on the stock and the trigger guard could not be locked down without inletting the receiver further down into the stock.

Our own Art Luppino added something that is very important. In his words, ďVertical center line between the stock ferule and the front band. I believe that this relationship is the Heart of performance... ď This is where the width of the receiver bedding area is so critical to the fit on a G.I. stock. If one side or the other of the commercial receiver is off from G.I. specs, it will cause the barrel to be pushed towards one side or the other at the front band/ stock ferrule interface. That will string shots all over the place. Along with that, if the commercial receiver is off G.I. specs enough, you wonít get good downward tension between the stock ferrule and the front band. A loose or incorrect fit there will also string shots all over the place. The only really good way to fix these things for many commercial receivers is to glass bed the action properly.

The next problem is something almost no one but an Armorer who works these rifles a lot really understands. That is the absolute necessity of having the correct distance from the top of the stock (under the receiver heel) to the bedding area for the rear of the trigger housing. On both the Garand and real, G.I. M14ís, this distance was between 1.700Ē and at most 1.725,Ē while the most usually found was 1.720.Ē That isnít much distance to play around with. The reason for setting this distance so exactly is so the bolt will cam the hammer down far enough for the sear to act properly and catch the hammer in semi auto firing. It also has to be far enough that the bolt isnít too close to and doesnít batter the hammer. If this distance is TOO FAR, then the sear wonít reset the hammer and you will have unintentional doubles, triples or even full auto firing. As the stock batters down from wear, the distance will close up, but it usually doesnít close up so much that the hammer gets battered too much. Well, thatís on a closely held tolerance G.I. receiver, but we arenít working with that exactitude with commercial receivers.

Commercial receivers not being held to such strict tolerances can give you real headaches with this problem. The position of the safety bridge is critical here as that sets the distance the bolt can go down in the receiver. The bottom of the receiver heel on commercial receivers is also different many times than G.I. specs. As such, to get a G.I. stock to work properly so the bolt resets the sear properly, one may have to either add or subtract from the surface of the bedding surface for the rear of the trigger housing. Iíve seen these problems with all semi auto M14 receivers, by the way.

I think I would tear my hair out if I tried to make a plain wood stock that would be a drop in fit for each and every commercial receiver out there. Grin. There really is that much difference in the different commercial receivers and even amoung the receivers from the same manufacturer over the years of manufacture. What I would like to see in a Commercial wood stock is have enough wood on it so it can be properly fitted to each receiver, but as far as I know - no one makes them that way.

Anyway, I hope you all now have a better understanding why your receiver may or may not work correctly with a G.I. stock.

Thanks from hughi and daddyLL
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Old March 11th, 2009, 06:03 AM   #2
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Thanks for a great post Gus. I was the one with a Wenig stock that would not allow the bolt to come all the way back and after you gave me the correct numbers, I found out the stock was
.052 under. Wenig replaced it with some teeth pulling.

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Old March 11th, 2009, 08:13 AM   #3
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Quote:
Originally Posted by Ionian View Post
Thanks for a great post Gus. I was the one with a Wenig stock that would not allow the bolt to come all the way back and after you gave me the correct numbers, I found out the stock was
.052 under. Wenig replaced it with some teeth pulling.
Glad you brought this up here. It's always great to get real world examples for other folks.

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Old March 12th, 2009, 10:17 AM   #4
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RE:Stock to Receiver Fit

Greetings,

My previous post on this topic is below. I just received Mr Different's DVD, which has an amazing quantity of detailed drawings. In it, I was able to find the specification for the distance across the receiver legs. It is 1.250" -.003". So, neither of my receivers is even close to spec. Hope this adds a bit to the discussion.

Regards, Jim



>>>My Federal Ord M14S (s/n 8851) is in a walnut stock that I'm prepping to refinish. I have a spare synthetic GI stock that I was going to temporarily install the receiver into. Well, it didn't fit! The receiver legs are too wide to even enter into the stock. SO, I took my Armscorp receiver out of its synthetic stock to see if that one would work; same problem.

I then measured the outside distance across the receiver legs of both receivers at the bottom. The Armscorp measured 1.270", the Federal 1.322". The Armscorp receiver fits into the walnut stock (it may be just slightly loose, hard to tell for sure).<<<

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Old March 12th, 2009, 11:31 AM   #5
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Thanks Jim.

Great info. The more such info we can add, the more it should help others.

Regards, Gus

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Old March 25th, 2009, 04:22 PM   #6
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I have a couple of rifles built on Armscorp rec. They fit GI wood stocks, but not GI glass stocks. I haven't gotten around to making the stocks fit the rec. Seems cheaper to mess with the stocks than grind on the rec.

And I thought I was the only one with this problem!

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Old March 25th, 2009, 08:01 PM   #7
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Quote:
Originally Posted by leonardc View Post
I have a couple of rifles built on Armscorp rec. They fit GI wood stocks, but not GI glass stocks. I haven't gotten around to making the stocks fit the rec. Seems cheaper to mess with the stocks than grind on the rec.

And I thought I was the only one with this problem!
The reason they fit the wood stocks better is because wood has more "give" than fiberglass.

You are absolutely correct the best way to fix this is to modify the stock and definitely not the receiver.

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