Receiver rendered inoperable by broken bolt - what are my options?

Hello,
Last weekend while firing my carbine I had a major bolt failure. I'm guessing that the bolt was not fully rotated when it fired, but in any case the main lug snapped and the secondary lug took a chunk out of the receiver as shown in the attached pictures. Luckily no one was injured - the backup lug performed its job perfectly in that regard!

Problem is - the receiver is now unsafe to fire. Both the CMP and Fulton gunsmiths have stated that repairing the receiver is outside of their means, and even if it does get repaired, there is a good chance that the receiver is partially to blame for the bolt's failure. Which leaves me with a 98% perfect receiver that is not safe to fire. Amazing what 1/16" of damage can do...

I've resigned myself to this fact, and am in the process of sourcing a new receiver, but I was wondering what my options are. I do not plan to keep the receiver, so I was planning to sell it (with large text in the title being NOT FOR USE). Would these forums be a good place to start?

EDIT: Noticed that I did not state what the receiver is - it is a Winchester SN 123XXXX

I've see this happen before, due to excessive headspace. In addition to the damage on the left side of your receiver, it might be bulged out here too. Can't tell from the pictures. It is basically scrap now, unsafe to fire, even if it is repair welded. USGI Receivers are heat treated 4140 Cr-Mo steel, and it is difficult to guarantee original strength on a repair welded receiver. Only exception would be a repair on a broken rear sight dovetail slot. Unfortunately, it's only good to make a de-activated wall hanger, movie prop, or a paper weight.

Before you sell it, you might want to further de-activate it, so someone won't try to use it as a firearm. Maybe drill a hole completely thru the receiver ring.

Was that a Universal Carbine? It is almost impossible for a USGI to fire out of battery because of the tail on the firing pin needing to line up with a notch in the rear receiver bridge. Later in production, Universal took production short cuts for $$$ reasons, and eliminated the safety feature. They can easily fire out of battery with the shortcut...

Quote:

---

Originally Posted by imarangemaster

Was that a Universal Carbine?

---

Last paragraph in the OP, its a Winchester.

I wouldn't even sell it, you're just allowing someone to put a touch of weld there and cold blue, and sell it as perfect. Destroy it yourself and be done.

Thanks for the responses.
I was hoping that there might be someone looking for it as a display piece, but it is much more likely that they would try to repair it. It sucks to have to damage it even more, but it's better than thinking about that possiblity...

Nothing could be worse than having someone obtain your defective receiver and pass it off as a functioning firearm. Cut it up, melt it and cast it into something useful. See if you can make it into a coin or something of that nature. Make it a fun project and write about what you've done with it.

Just a thought.

Couple of options drill the chamber and weld the barrel into the receiver underneath, smooth out the damage cold blue it, weld up the firing pin hole cut a slot under the barrel out of sight and have it in the man cave or strip it down pull the barrel and put a drop saw through the receiver part it out or keep the spares for your replacement carbine. Ensure you destroy the receiver either way so it can never fire a round again..... just my 3c worth.

OP.

The receiver is a paperweight now. Keep it and use it for that purpose.

This can happen with reloaded ammo that the case is just a little bit too long. It prevents the bolt from locking and allows the hammer to hit the firing pin and causing the round to fire and the bolt gets badly damaged and or the receiver does. It is the main reason that reloaders have to measure and trim their cases each time they size them. The sizing is what elongates the cases.

I bought a commercial M1 Carbine many years ago (in the 80s) that was caked with cosmolene (which I though was odd...) After I broke it down and detail cleaned it found it was a re-weld receiver. It took some threats, but i got a refund. Now, being older and wiser, I know caked cosmolene is ofter camouflage for problems.

Re-weld? Do you mean it was welded when built then welded again because of breakage or wear?

Quote:

---

Originally Posted by noobzor99

Hello,
Last weekend while firing my carbine I had a major bolt failure. I'm guessing that the bolt was not fully rotated when it fired, but in any case the main lug snapped and the secondary lug took a chunk out of the receiver as shown in the attached pictures. Luckily no one was injured - the backup lug performed its job perfectly in that regard!

Problem is - the receiver is now unsafe to fire. Both the CMP and Fulton gunsmiths have stated that repairing the receiver is outside of their means, and even if it does get repaired, there is a good chance that the receiver is partially to blame for the bolt's failure. Which leaves me with a 98% perfect receiver that is not safe to fire. Amazing what 1/16" of damage can do...

I've resigned myself to this fact, and am in the process of sourcing a new receiver, but I was wondering what my options are. I do not plan to keep the receiver, so I was planning to sell it (with large text in the title being NOT FOR USE). Would these forums be a good place to start?

EDIT: Noticed that I did not state what the receiver is - it is a Winchester SN 123XXXX

---

Sorry to hear about your Winchester M1 Carbine. Before I would do anything about fixing your receiver. I would have the receiver checked against the original drawing to see if the receiver has been changed by stretching. Next I would get the reciever magna fluxed to see if there are any hidden cracks or breaks. (other than the left lug). With the original drawing I would send the receiver to a company that specializes in micro laser welding and have the left lug rebuilt to spec. Micro laser welding is strong and does not spread a lot of heat over a wide area like TIG or MIG welding. The problem is going to find someone to do the work. Just a thought.

--fjruple

What is the reason that "missing chuck" from the receiver behind the bolt's left lug needs to be repaired? The bolt's left lug is UNSUPPORTED in a "normal" carbine throughout the firing process. I'm not sure why it's even there except perhaps to provide general guidance for bolt travel when unlocked.

FWIW, at least one of my carbines has a similar "missing chunk" from that corner of the receiver as it came to me directly from the CMP. Presumeably they inspected it and I thought it was in fact "normal" at one time (my drawings aren't particularly clear in that area) but I have since been shown over on the CMP boards that it was due to breakage as it is obviously different from "new". But this carbine has fired thousands of rounds full auto in my possession without so much as a hickup. So I ceased worrying about it.

Knock on wood

The Carbine was designed to have contact on both lugs of the bolt. On all 3 of my Carbines, both bolt lugs have contact with their corresponding locking shoulders in the receiver. If yours don't, I'd be trying to figure out why.

It may function OK for awhile, but with only the right lug contacting, I see a broken bolt in the future.

Quote:

---

Originally Posted by jakester

The Carbine was designed to have contact on both lugs of the bolt. On all 3 of my Carbines, both bolt lugs have contact with their corresponding locking shoulders in the receiver. If yours don't, I'd be trying to figure out why.

---

It helps to have original references. Your eye is probably not precise enough to measure small gaps

Drawings for both bolt (7160092) and receiver (6544004) specify that the left rear surface (of left bolt lug and left receiver notch)
shall be within 0.001" to the rear and 0.003" forward of right hand locking surfaces.

Since there is/was no "fitting" of specific bolts to specific receivers, only one of the bolt lug's rear surfaces may contact the receiver at any given time. In effect, this clearance means that, by design, only the right lug in contact with receiver supports the bolt during fire.

If that lug breaks during fire, then all bets are off and the left lug will contact the receiver in a fashion it was not designed to do.

Quote:

---

Originally Posted by CrossedCannons

It helps to have original references. Your eye is probably not precise enough to measure small gaps

Drawings for both bolt (7160092) and receiver (6544004) specify that the left rear surface (of left bolt lug and left receiver notch)
shall be within 0.001" to the rear and 0.003" forward of right hand locking surfaces.

Since there is/was no "fitting" of specific bolts to specific receivers, only one of the bolt lug's rear surfaces may contact the receiver at any given time. In effect, this clearance means that, by design, only the right lug in contact with receiver supports the bolt during fire.

If that lug breaks during fire, then all bets are off and the left lug will contact the receiver in a fashion it was not designed to do.

---

Unfortunately, I, unlike you, do not have access to a set of Original Carbine drawings, so I do not know what the dimensions are, or should be.

However, my eye's are precise enough to notice distinctive wear patterns on the left bolt lug locking surface, and corresponding wear on the receiver locking shoulder. All of my Carbine's are like that.

None of my Carbines appear excessively worn, so I doubt my right bolt lugs, or the right receiver shoulders, on all three Carbines are worn down to the point where I now have contact on the receiver locking shoulder with the left bolt lug. The more believable scenario is that they were designed that way...

I will add that I find it hard to believe that the Winchester Engineers who designed the Carbine, would design a firearm with only one bolt/receiver locking surface. Surely the Ordnance community had learned their lessons with the Krag.

I can also see that were are likely to never agree on this, so as long as you're happy with yours...

Quote:

---

Originally Posted by CrossedCannons

What is the reason that "missing chuck" from the receiver behind the bolt's left lug needs to be repaired? The bolt's left lug is UNSUPPORTED in a "normal" carbine throughout the firing process. I'm not sure why it's even there except perhaps to provide general guidance for bolt travel when unlocked.

FWIW, at least one of my carbines has a similar "missing chunk" from that corner of the receiver as it came to me directly from the CMP. Presumeably they inspected it and I thought it was in fact "normal" at one time (my drawings aren't particularly clear in that area) but I have since been shown over on the CMP boards that it was due to breakage as it is obviously different from "new". But this carbine has fired thousands of rounds full auto in my possession without so much as a hickup. So I ceased worrying about it.

Knock on wood

---

Hmm. Yeah, the CMP made it clear that the receiver might be to blame for the bolt failure in this situation - and that if this is the case it will keep breaking bolts.
The other possibility is that the recoil spring is too weak and did not have the power to fully rotate the bolt, which led to a partially rotated OOB.
In any case, I am replacing the recoil spring and receiver. It really looks like the carbine fired without the bolt being fully locked either way, and that does not seem safe to me. The backup lug performed well this time, but now that it is half gone I don't want to think about what could happen if the same situation occurs...

In case anyone is interested I was using run of the mill PPU ammo - I don't think the ammo was to blame. I also did check headspace on the rifle when I got it and the bolt would not close on a field gauge.
Makes me wonder - if I had spent the $5 on a replacement recoil spring earlier...

Quote:

---

Originally Posted by noobzor99

if I had spent the $5 on a replacement recoil spring earlier...

---

Don't second guess yourself...if your aunt had a couple things she'd be your uncle... What happened, happened and if you aren't hurt, then that's sometimes as good as it gets. I broke a receiver and simply parted out the carbine and carried on. Too bad to, it was a second serial number block Winchester...(parts gun)

Quote:

---

Originally Posted by shadycon

Re-weld? Do you mean it was welded when built then welded again because of breakage or wear?

---

It was a de-milled receiver that was re-welded and re-parked. They were not uncommon in the 60s and 70s.

WELDED? Originally machined reciever-cut to be de-milled-"WELDED" back together!!

Re-weld= welded more than once! Just my interpretation.

The main thing is you and no one else was hurt, you have identified the suspect, made the changes so no one else will get hurt and probably enlightened some folk here on what to be looking for to me that's a win win as you still have a Carbine for parts minus the receiver for when you buy a new one.

Quote:

---

Originally Posted by shadycon

Re-weld= welded more than once! Just my interpretation.

---

Same here. Reminds me of re-imported carbines vs. imported. :beerchug: - Bob

Quote:

---

Originally Posted by shadycon

WELDED? Originally machined reciever-cut to be de-milled-"WELDED" back together!!

Re-weld= welded more than once! Just my interpretation.

---

Haha! Gotcha