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Posted By: gil russell Winchester M 12 question (OT) - 10/07/22 07:52 PM
I have a shortened M 12/12 ga original factory (vent) rib barrel (now shortened because it came in with a Polychoke, but otherwise in almost perfect shape). I finally found a barrel extension. Stupid me, I didn't even consider the dilemma: the barrel extension won't, of course, go on because of the rib. Now what?
Posted By: Run With The Fox Re: Winchester M 12 question (OT) - 10/07/22 09:31 PM
Solid rib, or ventilated rib? RWTF
Posted By: gil russell Re: Winchester M 12 question (OT) - 10/07/22 10:19 PM
RWTF: Vent rib (added after the initial posting)
Posted By: GLS Re: Winchester M 12 question (OT) - 10/07/22 10:35 PM
How long was the extension? The barrel you have can be threaded to accept a barrel section which is also threaded--and choked with or without a rib on the section added. Any barrel and choke man can do it. Gil
Posted By: Run With The Fox Re: Winchester M 12 question (OT) - 10/08/22 12:23 PM
Gil has it--good advice, and there are still some gunshops with qualified ' smiths who can help you with this worthwhile project. Let us know how it turns out.. RWTF
Posted By: Kutter Re: Winchester M 12 question (OT) - 10/08/22 01:09 PM
When you say Barrel Extension (Model 12, 42, 97) ..this is what I immedietely think of and this is what Winchester called the Barrel Extension.

[Linked Image from i.ibb.co]

Is this what you want to install on a stripped VR bbl so it can be then used on a M12 TD frame shotgun?

...Or by Bbl extension are you saying a cut off portion of a M12 bbl that includes the muzzle to use to put the VR bbl back to orig length. Thread and screw onto the muzzle in place of the former PChoke.

If it's the former,,the Winchester Bbl extension.
Since the stripped bbl needs to screw into the Bbl extension, The added lug for the VR sitting on top of the bbl is right up against the front edge of the bbl extension.
The VR itself is easily removed by punching the pin(s) out and sliding the rib forward and off of the posts.
But that still leaves that rear attachment lug in place of course and in position. The lower magazine tube portion of the bbl extension swings around and hits the VR lug and stops everything right there.

On some installs, the lug spans the bbl & bbl extension joint when installed so you can never take the bbl itself out of the bbl extension w/o first unsoldering that back lug.

Those added lugs are Hard Soldered in place ('Silver Soldered' to us older folks).
Posted By: gil russell Re: Winchester M 12 question (OT) - 10/08/22 01:26 PM
Kutter/Jim Yes the part in the photo is the one I am trying to use; the magazine tube guide (for lack of a better term) prevents it from turning more than 1/2 turn--as it is now. It seems like part of the rib would have to be removed then reinstalled later(after the barrel ext. is on) for it to make it all the way around--however many turns it would need. Am I looking at it correctly?
Posted By: Chuck H Re: Winchester M 12 question (OT) - 10/08/22 06:54 PM
Gil,
Your current problem of the rib lug notwithstanding, you will also run into some more technical issues with putting a new barrel on the gun. The M12 has a part labeled as a "barrel chamber ring" (#12 in the Numrich illustration) that is match reamed to the barrel chamber after the barrel is installed on the receiver. The reamer is a pull-through type arrangement, where the drive rod is inserted from the muzzle and the reamer locks onto it on the breach end. This alignment is critical to the function. A handful of years ago, I had a M12 refinished and this part was removed during the process and somehow either a part from another gun was installed or the original was clocked differently. The results were a non-functioning gun after the first shot. My advice on this particular work would be to have Simmons do it.


https://www.gunpartscorp.com/gun-manufacturer/winchester/shotguns-win/12-win
Posted By: Kutter Re: Winchester M 12 question (OT) - 10/08/22 08:20 PM
Originally Posted by gil russell
Kutter/Jim Yes the part in the photo is the one I am trying to use; the magazine tube guide (for lack of a better term) prevents it from turning more than 1/2 turn--as it is now. It seems like part of the rib would have to be removed then reinstalled later(after the barrel ext. is on) for it to make it all the way around--however many turns it would need. Am I looking at it correctly?


Yes, you have it right.
The first standing post (a block actually about 3/4" long) at the breech end of the bbl for the rib attachment is what is blocking the bbl extension from being unscrewed from the bbl itself.
The 1/2 turn is all you can do as the lower portion strikes that block as it comes around.

The rib itself slides off of the post(s) once the cross attachment pin(s) are removed.
But the block and all the other upright posts are silver solder/silver brazed into place.

You can unsolder that offending block. The usual method of putting these in place was to mill a shallow slot for the bloc to sit in in the top of the bbl.
So removing it and then replacing it is generally not difficult as far as proper placement (mark it for forward facing before removal is helpful)

Once off,,the bbl extension can be turned into place and clocked to proper 12 o'clock position.
It's actually better to do all the new refitting before re-soldering the rib block back on just incase things aren't quite right and you need to go back and re-adjust or remove the bbl extension again.

Removing and installing te Bbl Extension is NOT a job for a big cresent wrench.
The part is very fragile especially on the lower area where the op-rod cut is.
Trying to bring it around the last few degrees of turn will in most all instances collapse that magazine tube section if you don't support the Extension w/a proper shaped tool.

There are (or were) factory style wrenches for this when the guns were more popular.
You can make a simple wrench with flat steel, some turned pieces to fit both the chamber and the mag tube ID's.

Here's the one I made. Crude looking but it works and have never ruined an extension.
It's set up for 410 M42 now in the pic.

[Linked Image from i.ibb.co]
[Linked Image from i.ibb.co]
[Linked Image from i.ibb.co]
[Linked Image from i.ibb.co]



The handle is a simple piece of flat steel,,probably 18" long.
The working end has the chamber plug. You need to turn plugs of the different gauges you need. They need to slip fit into the chamber of the bbl the extension is being removed/installed on.
Simple threaded stud on the back end and a nut and washe attachment to the handle.
I wrap the chamber plug with a turn of news print to avoid any marks in the chamber

Below the chamber plug is a similar Magazine support plug.
Same idea as the above but this plug fits the gauge specific mag support on the bbl extension.
The slotted handle allows for these different gauge plugs to be adjusted to fit the different size Bbl Extensions.
You can use a lead hammer on the end of the handle if need to loosen or tighten the Extension w/o any fear of twisting or damage to the part.

The magazine plugs are turned for a close fit as well and then need aa little hand file fitting to put some slight 'flats' on the side to fit correctly into the hole.

Set everything up into the Extension after hand turning the Bbl extension onto the bbl.

The Bbl should be secured in a real Bbl Vise w/proper fitting jaws.
I use wood,,I use cast lead. I always use rosin.

It'll take a a few on and off trys to get it to clock up correctly.
I take any matrl off of the front face of the Extension,,a nice broard flat surface and it cuts cleanly with a sharp med or fine cut file.


All this high temp braze work destroys the bluing of course, so polish and reblue is a must.
The work from Simmons and others always came back reblued. Some polishing better than others.

Solid ribs on these bbls are soft soldered on. so Rust blue only for those. But hot salt blue is fine for the VR bbl assemblys.

Factory work was done on parts in the white, so then the Factory polishers went to work and the work was much better.
Then blued.
Factory proofing was done when all work was finished. Proof mark stamped 'thru' the bluing. VR and SR bbl proof mark on the left side of the bbl by the breech unless factory engraved. Then the proof is generally out at the end of any scroll work engraving (if any)done on the bbl'


**
If the bbl being done is for an Xtra bbl for an existing M12,,then the Original Bbl Chamber Ring mentioned above that is already in the frame should be set for Headspace with that Original Factory barrel as it came from New Haven.
Should check with a gauge anyway.

In fitting up this as an Extra Bbl, you do not want to change that Chamber Ring. Doing that will change the HS on the Original Bbl assembly.
To fit this new Bbl assembly for headspace AND to keep any original Bbl assembly in spec with the Chamber ring that is still in the gun,,,the HS on this new Extra Bbl assembly would need
to be set by reaming the chamber in the bbl itself to a proper HS spec.
The extra bbl assembly should then be ser#'d to the frame. That shows it's fitted and HS to that frame.

That way both Bbl sets will HS properly when checked on the same Frame and the same Chamber Ring in place.

There may be no need to change, adjust for any HS at all. Often the HS will be just fine.
A gauge will tell. These were close fitted parts but they still made allowances for hand fitting so such changes could be made

If this new bbl assembly is simply being fitted to an orpan frame, then HS can be set by adj/reaming/replacement of the Chamber ring or by reaming the bbl chamber back edge itself.
The proper way would be the former as you are working on the replacable part,,the chamber ring.
But lots of things have been done to M12 parts and bbl assemblys over time so you never know what you have till you start to assemble things.
Kind of like '..The transmission was a '53. And the motor turned out to be a '73. And when we tried to put in the bolts all the holes were gone.'
Posted By: eightbore Re: Winchester M 12 question (OT) - 10/08/22 08:35 PM
Thanks for the information and pictures. However, the basic question is "Who does this work of exchanging barrels on Model 12 and 42 Winchesters?" I mean taking barrels off of extensions and putting another barrel on the extension. Thanks for that added piece of information. I have a couple of projects that need completion.
Posted By: Brittany Man Re: Winchester M 12 question (OT) - 10/08/22 10:57 PM
Kutter,

You are an example of what everyone who posts on this forum should aspire to. No agenda, no B/S, good, solid, helpful & to the point information on the OP's question. Thank you!
Posted By: eightbore Re: Winchester M 12 question (OT) - 10/10/22 09:17 PM
I wonder if someone could answer my question. Who can change barrels on extensions? Are those of us who need this job done completely out of luck?
Posted By: GLS Re: Winchester M 12 question (OT) - 10/10/22 09:52 PM
Should anyone desire to see a 45 page gunsmith manual on the M12 (and a handful of other pistols and long guns), pm me your email address. All are contained in a PDF.
Gil
Posted By: Kutter Re: Winchester M 12 question (OT) - 10/10/22 10:54 PM
Simmons Gun Repair would be a good place to inquire if they still do the work on M12 and 42's.

They did the ribs for Winchester for many years. They were still doing M12 and 42 ribs for customers as of a few yrs ago


MidWest Gun Works doesn't list doing any M12 work gunsmithing. Just a source of parts still.
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