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Cracked M1A1 Receiver


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#1 michael

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Posted 21 May 2020 - 09:36 PM

Found this gun for sale locally but inspection revealed these cracks. If priced appropriately is the gun salvageable as a safe shooter? I attached some pictures. Thanks.

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#2 Black River Militaria CII

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Posted 21 May 2020 - 10:17 PM

Sure. To do a proper repair, the barrel needs to be removed which will allow the forestock bracket to be removed. Clean the park off, prep the cracks by beveling the edges for the weld fillet and do the weld. Clean up the weld and repark the receiver and other parts so they match. M1's weld really well!
The cracks in the picture have no effect on the function or safety of the gun. FWIW


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#3 Paul in PA

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Posted 22 May 2020 - 09:09 AM

If the price is right you got a shooter. 


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#4 TD.

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Posted 22 May 2020 - 09:15 AM

I suggest an estimate of repair from someone like Black River Militaria CII, who I am sure is more than qualified to make the repair. Given the price of registered guns, I would want it repaired by one of the best. If not Black River, I would reach out to PK. 


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#5 reconbob

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Posted 22 May 2020 - 04:01 PM

   I agree with Bob that the crack does no harm. Anything mechanical or pressure-wise 

is not happening in that area. If you want you could shoot the gun and see what happens

over time.

 

   This is an interesting failure of the receiver. I wonder if it was caused by force being

applied to the grip mount prying it away from the receiver? Or was the grip mount too

big or the slot too small and driving the grip mount into place stressed the steel causing

the crack?

 

   

Bob


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#6 mohawk64

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Posted 22 May 2020 - 04:23 PM

I agree. Someone got a little crazy with the grip mount puller
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#7 anjong-ni

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Posted 22 May 2020 - 07:57 PM

At work we keep equipment a long time and end up welding lots of cracks. 

 

The damaged part seldom ends up as strong as it originally was because the properties of the base-metal are usually destroyed by the welding heat. 

This usually calls for "re-inforcement" in the area of high-stress. Extra metal to help out in the weak spot. Triangles, gussets...

 

That said, this looks like it could have been a "big over-stress moment". Maybe someone yanked on the sling. Weld it up and enjoy it.

 

Metal-fatigue gets everything eventually.          Welding broken stuff back together for 55 years...Phil


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#8 john

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Posted 24 May 2020 - 09:54 PM

My best guess is because of the visible rust and pitting down in and next to the grip mount....I believe the gun got wet and either froze with water down in and around the grip mount or the rust grew inside, forcing the metal apart. It's not a crack from side stress but you can see the metal has pulled apart on both sides of the split.
Best guess is freezing....that generates an incredible amount of force.....just my .02 cents....

Edited by john, 24 May 2020 - 09:55 PM.

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#9 NFA amnesty

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Posted 24 May 2020 - 10:13 PM

My best guess is because of the visible rust and pitting down in and next to the grip mount....I believe the gun got wet and either froze with water down in and around the grip mount or the rust grew inside, forcing the metal apart. It's not a crack from side stress but you can see the metal has pulled apart on both sides of the split.
Best guess is freezing....that generates an incredible amount of force.....just my .02 cents....

That could be a good selling point....This weapon saw action in Korea in the winter of 1950!  I think you are right about moisture getting inside and then freezing.


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#10 1921A

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Posted 25 May 2020 - 09:51 AM

Ive seen similar damage from barrel removal attempts by inexperienced people. Hitting the grip mount with the barrel wrench/vise, as a barrel breaks free, can crack the side of the receiver nose.

I mentioned this possibility because it happened to an M1 I had during a barrel replacement procedure. It was done by a trained gunsmith who thought he knew what he was doing. He fixed the damage but I still know its there.

For those of you who are acquiring barrel removal tools just keep this in mind. If you are new to this its an easy and costly mistake to make. Dont practice on your Colt gun!

These tools have more than enough leverage and force to split the side of the nose if used improperly - Ive seen it happen. You see loose or sprung grip mounts on military guns that have seen hard service - and usually its a riveted grip mount. No doubt this condition is caused by over active pulling on the sling and fore grip. In nearly 40 years of working on these guns Ive never seen a receiver nose cracked in this way - could happen I suppose, but Ive never seen one.
Just my opinion.

1921A

Edited by 1921A, 26 May 2020 - 12:30 PM.

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#11 laurencen

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Posted 25 May 2020 - 10:05 AM

that's a odd way to crack, the grip mount clearly is forced away from the barrel and does the split also go to the barrel? water freezing would be my guess of the culprit, years ago had a trailer fabricated, the vertical tube around the door was not capped or a drain hole in the bottom, the water expanded the tubes from 2 x 1 to 1 1/2 round at the base and finally split, this was 0.1" wall tube so freezing is powerful


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#12 Black River Militaria CII

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Posted 25 May 2020 - 10:54 AM

No where enough volume of water could accumulate in the seam of the tight slot to freeze and expand with sufficient increase in volume to crack the metal. The rust is superficial. The sharp inside upper 90 degree edge of the slot provides a weak point for generating a fracture if sufficient torque is applied to the bracket forcing that edge of the bracket up. For instance, a pistol grip mounted on the bracket and twisted sideways with enough force could do that. FWIW


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#13 mnshooter

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Posted 25 May 2020 - 07:15 PM

Both sides about equally cracked, I'll go with someone just pushing up and down way too hard, trying to break it free.

That works pretty well to get a stuck fence post out of the ground; not so well here.

Or, clamping the grip mount in a vise, and failing to support the receiver, to insure strikes on the nose are vectored in alignment.


Edited by mnshooter, 25 May 2020 - 07:29 PM.

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#14 anjong-ni

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Posted 26 May 2020 - 08:08 PM

Would be fun to saw-off the fissured-sections and check the cracks for "beach marks"....Phil


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#15 giantpanda4

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Posted 26 May 2020 - 09:35 PM

Phil, no fatigue cracks there. I got my money on someone bending the crap out of the grip mount and not knowing what they are doing.


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#16 TD.

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Posted 27 May 2020 - 09:24 AM

This may serve as a good lesson for those with the tools to remove and replace a Thompson barrel and/or grip mount but without a lot of experience in this area. I have watched several members remove and re-install several barrels and they are quite good at it. That said, they learned by watching others with experience that knew what they were doing. It appears bending the grip mount down to much to insert part of the barrel wrench can be very unforgiving. From what I recall, the grip mount only has to be moved a very small amount to insert the wrench. Perhaps, reconbob, PK and Black River Militaria CII can share their best practices involving moving the grip mount. No doubt, all have removed and re-installed a lot of Thompson barrels.  


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#17 anjong-ni

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Posted 27 May 2020 - 07:23 PM

On page 43 of Doug's catalog was his tool to gingerly hold the resting-bar away from the barrel to get the wrench on it...Phil

 

http://www.sturmgewe...nCatalog72A.pdf


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#18 reconbob

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Posted 27 May 2020 - 10:19 PM

The rule of thumb when doing barrel work is to retract the grip
just enough to get the barrel wrench on.
I don't think the crack on the receiver being discussed here was because
somebody over-did it barreling the gun. I think that some other excessive
bending force was applied to the grip mount, and maybe the grip mount
that is currently on the gun is not the one that was there when the damage was
done. Strange things can happen, to wit:

A short anecdote I have told before....when I worked at Sarco eons ago
he either won an auction or had a contract to buy all of the guns damaged in
in the mail that accumulated at the Newark NJ postal center. My job was to
strip the guns of useable parts, etc.
One gun was a Remington M513T .22 rim fire target rifle with a 1" diameter
bull barrel. The rifle was new - did not have a scratch on it and the end of the barrel,
which also did not have a scratch on it was bent all the way around like a candy
cane. The stock and the rest of the gun was in perfect condition. I put a new barrel
on and it went out to the showroom. We could not imagine any way the barrel
could have been so bent and leave the rest of the gun, including the stock,
undamaged.

So who knows what could have happened to this gun and grip mount....

Bob
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#19 anjong-ni

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Posted 29 May 2020 - 07:07 PM

Love pictures of metal things that "worked-'til-the-end"...Phil

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#20 2ndArmored

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Posted 29 May 2020 - 08:23 PM

Although this may get moved to the STEN page, this sear goes well with the current theme of  "Land of the Cracked and Broken".   For those unfamiliar with the Thompson's British cousin, there should be metal where the red arrow is pointing.  There used to be but ain't no more.

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Edited by 2ndArmored, 30 May 2020 - 09:21 AM.

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