Barrel Repair

[alfajim]

Hi guys, back on again, been dealing with a few difficulties physically knee and back all fixed back to normal and also a big move from SF Bay area down to the central valley to be by Grand kids.
Awhile back I made mention of having picked up a new Trapdoor barrel and receiver off the bay that had been damaged with a cutting torch I got it apart and repaired the end of the barrel with a little weld. I remember someone remarked that he had repaired some of them in the past. I would like to get the repair machine work done to finish it so need a reference and or if he is browsing get back to me on it. Also debating having it made into a 45-90 if someone has the correct reamer? And will it work OK with the three lands and grooves 1-22 twist at 45-90?

Jim O

[mdeland]

It would probably be OK pressure wise if the weld is external and at the muzzle but I would never trust a weld on the breech end in the chamber area.
At the weld it will be either softer or harder than the normal barrel steel so I don't care for any higher temperatures than the barrel steel was normalized at.

[John Bly]

I've repaired a few of them, not by welding but by cutting off the damaged part and boring into the chamber a short ways. I then make up a sleeve from a cut off chrome moly barrel to fit into the chamber that is long enough to make up the cut off part. I install it with permanent loctite and a slight press fit.
Then I chamber it and refit it to the receiver. When finished the repair is not seen and it appears to be just as it was when it left Springfield. The chrome moly insert is stronger than the original barrel and it is captured between the receiver and original barrel. PM me if you are interested in this repair.

[SSShooter]

John's repair seems to work pretty well in 45-70 (can't comment on 45-90). He has beaten or tied three (4? maybe) national records and won the Trapdoor Challenge at the SE Regional more than once with his. Personally, I think its his spotter.

[alfajim]

The actual damage was under the extractor slot towards the bottom of the end not real deep, had a welder that is expert in repairing, "reconstructing" aluminum blocks, fabricating racer car chassis, and headers of stainless and titanium. Not worried about the weld as he picked the correct rod type and used a TIG welding machine. It just needs to be faced off and the rim recess cleaned up at the weld and the extractor slot cleaned up thought I could use a dremel with a cut off disk. Slight clean up required on the outside at the weld.

After moving I lost access to the lathe to do it myself I was going to fab a pair of round jigs to hold threaded end, shrink fit, and one to slip on the barrel at the other end of the spindle with the correct taper to hold on center at both ends.

Jim O

[mdeland]

Yes, Johns sleeved chamber repair is perfectly safe. I have seen 8MM Mauser's with a sleeve soft soldered in place and it appeared to have worked at least for a while. The joint at the front needs to be behind the mouth of the case and should be very tight and taper fit. At 45-90 black powder pressures it should be permanent if well executed.

[mdeland]

It's not really the quality of the weld that is so important but rather the hardness differential and unpredictable ductile character change in the barrel steel strength, the weld produces. The main stress in the chamber area is hoop stress and shock load which a 4140 barrel steel chamber sleeve as John mentioned would address with safety.

[mdeland]

Personally I would sweat the liner in with low temp silver solder like (Force 44), for maximum strength and void-less close fit.

[alfajim]

I've repaired a few of them, not by welding but by cutting off the damaged part and boring into the chamber a short ways. I then make up a sleeve from a cut off chrome moly barrel to fit into the chamber that is long enough to make up the cut off part. I install it with permanent loctite and a slight press fit.
Then I chamber it and refit it to the receiver. When finished the repair is not seen and it appears to be just as it was when it left Springfield. The chrome moly insert is stronger than the original barrel and it is captured between the receiver and original barrel. PM me if you are interested in this repair.

John the chamber itself was not damaged it was part of the end by and below the extractor slot taking away part of that plus down and out to the receiver it actually welded the barrel to the receiver at the deepest part of the cutting. I could not get the barrel to unscrew no matter what I did having to destroy the receiver to get it off.
I could have used it as is but the extractor would not have worked well no support.

[mdeland]

So the receiver has had weld heat as well in the extractor area which is the most critical part of receiver strength (threaded receiver ring)? Or when you used the term weld did you mean locked up? I would not trust it if the former! I just re-barreled a trap door about two months ago and am thoroughly acquainted with threading, chambering and indexing a barrel to the receiver. You might get away with it for a while at least but it is not a safe repair in my opinion if the receiver has been welded at all.

[alfajim]

So the receiver has had weld heat as well in the extractor area which is the most critical part of receiver strength (threaded receiver ring)? Or when you used the term weld did you mean locked up? I would not trust it if the former! I just re-barreled a trap door about two months ago and am thoroughly acquainted with threading, chambering and indexing a barrel to the receiver. You might get away with it for a while at least but it is not a safe repair in my opinion if the receiver has been welded at all.

I have another receiver as I had to cut that one apart to get it off. It just would not unscrew even with the barrel lock up in a lathe chuck and using a 18" crescent wrench plus heat was just to firmly attached in one spot about 1/16th" BOO!

Jim O

[mdeland]

You did think to remove the breech block and extractor before trying to turn the barrel out of the receiver,right? Some of those guns that have never been apart since they were built need a proper barrel vice and action wrench along with a bit of heat to get them loose.

[alfajim]

You did think to remove the breech block and extractor before trying to turn the barrel out of the receiver,right? Some of those guns that have never been apart since they were built need a proper barrel vice and action wrench along with a bit of heat to get them loose.

It was a bare receiver barrel assy. Really was disappointing to have to destroy the receiver as both of them being brand new! BAH!

Jim O