inspired by Madcap

[ssgross]

my model 12 barrel came in. measures 21 inches from the breech...but now I know why it was sold. The barrel extension was overclocked, with the witness marks off by no more that 1/16 inch. I removed the outer adjustment bushing, clamped the barrel in my barrel vise, and took the extension off pretty easily with a big crescent wrench. Looking at the part, the extension stops with the witness marks lined up, but doesn't torque there. Of course when it was on, the bead was noticeably off.

It can likely still be salvaged. We aren't talking that much, just a bit of a shoulder crush. I can (a) try to lightly peen the barrel shoulder, (b) use some aluminum tape and a razor blade to make spacer, or (c) flux the faces, put it on, clean off all the flux off the outside, back it off a hair, sweat in some solder, and tighten until aligned, polishing off any excess.
Or (d) any better idea any of you have. I think (a) and then (b) if that fails would be fine. Solder is overkill. Hell, I don't know the torque spec anyway. should probably figure that out before I change my name to bubba I don't even have a shotgun yet!

EDIT: I know these won't be easy projects...proper fit of the chamber ring, etc. and etc., but I'll see how far I can take it before I get stuck.

Information

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[browningautorifle]

The barrel extension was overclocked

Usual procedure would be to give it one more complete turn and rechamber it.

[ssgross]

Usual procedure would be to give it one more complete turn and rechamber it.

hmm. it didn't take very much at all to get it off, and there is no serial number on the extension. maybe it wasn't overclocked at all, and just snugged up by hand. not knowing how tight they are supposed to be makes me wonder if it is supposed to get another turn. I'll try to measure the threads and see how much crush I'll get on the shoulder. the threads are very, very fine. if I tighten with my just my hands and manly grip strength, I get the marks lined up where they were...slightly past alignment.

the '97 on it's way needs a new extension, so I'll have another to play with.

EDIT: looks like 32 threads per inch, which would be about 30 thousandths forward with another turn. I'll wait until the shotguns get here. Numrich has new replacement extensions, which I need one anyway for the 97. I'll see if one of those are any better. Jim, you're great at pointing out how much I wish I had a lathe by now

[browningautorifle]

how much I wish I had a lathe by now

Worst thing is...I was about to ask again whether you had one or not. That would have just added.

wonder if it is supposed to get another turn

They do have quite an amount they can be adjusted too. That was the whole idea. Remove the screw, slip the keeper and turn the ring a couple of notches. Lock it up again and try it.

[ssgross]

Worst thing is...I was about to ask again whether you had one or not. That would have just added.

I've gotten very close to dropping on one, even closer when beer is involved with the decision making process. I'm afraid though if I did, I'd have to give up my brewery in the garage to make room. It would make it harder to move too when I'm finally through with the rat race. No, I'll wait till my kiddos are safely on their way to adulthood, then early retirement, teach part time and maybe hang my shingle out somewhere quiet with 1,000yds in the backyard.

They do have quite an amount they can be adjusted too. That was the whole idea. Remove the screw, slip the keeper and turn the ring a couple of notches. Lock it up again and try it.

All the reading about "wearing over time" and people's woes trying to tighten back up and realign made me look long and hard at the schematics of the design. It looks to me like the only source of "wear" that would cause the barrel/receiver mating to loosen up is the metal-on-metal friction between the forward face of the chamber ring and the breech face of the barrel, when twisting in and out, and maybe from vibrations under recoil. Thus the recommendation from most of not taking the forend off with every cleaning, etc. I would think, on the other hand, that a little very high temp lubricant, like a nickel anti-sieze, on the surface of the chamber ring, would add to the longevity.

I think me, as well as Madcap's project, will need to find those 3 reamers, and likely a special tool to install chamber rings, or resort to sending out when we are all done. I read an account from an old winchester employee somewhere else that the final chamber ring alignment and barrel fitting was done at the very end, after all the bluing and fitting of everything else. If that's the case, then we have plenty of time to figure it out.

From the description of fitting a chamber ring, it looks like 1) special tool to screw it into place 2) a tiny set screw to lock it in place 3a) a tapered reamer, just narrow enough to clear the choke if present, is pushed from the muzzle only to rough cut the ring, and align the hole to the bore. 3b) stubby pull through finishing reamer to finish the ring flush to the chamber (don't forget some mandrels in the bore to maintain alignment), then 4) rimmed pull through reamer to set the final headspace.
Given the function of each step, I'd think it shouldn't be hard to have a set made by, say, calling Dave Manson.

[browningautorifle]

I've gotten very close to dropping on one

When you do, spend what you need to and get the right one. Consider your threading issues and through bore when buying. Bigger is better.