Building a Winchester Model 12 upper

[JoyfulJoker]

I recently came into possession of a 1947 Winchester Model 12 in 12 gauge. It has a modified choke barrel on it , although it is not original to the gun, the receiver extension has no number. It also came with a separate Full choke barrel. I read that unscrewing the barrel from the receiver extension causes wear on the threads. I want to avoid unnecessary damage.

My question is : Can I Frankenstein a separate upper around the Full barrel? If I want to change from modified to full , it’s just a matter of pushing the pin and twisting it off and changing uppers . Would this be something that would require a knowledgeable gunsmith to piece together ? The parts are available on line.

While worn , it’s in great shape with expected wear. It’s a shooter, not a collector.

Thank you.

[highpower]

Yes you can and it's not hard. The M12 was designed to be able to take up wear between the extension and receiver.

I did it with my M12 a couple years ago. It went from this with a small amount of play:


To this. I adjusted it so it is now rock solid:

[W.R.Buchanan]

Pretty much all Takedown Systems have a feature that allows adjustment.

I don't think you could wear out that feature on that gun in 3 or 4 lifetimes.

Randy

[19K]

My 1897 was built in 1912. I just recently adjusted it 2 positions more to tighten it up. It has about 8 more adjustments to go.

[JoyfulJoker]

Thank you for the answers. The shotgun is in perfect shape and I’m happy with it. It’s still on the first notch .

So I have a complete Model 12 with a mod barrel that is in perfect shape , fits tight. No problems.

The shotgun also came with an extra Full Choke barrel for a total of Two barrels.
The extra barrel is just a plain barrel , no mag tube , just a barrel.

I don’t want to unscrew the mod barrel to try the extra Full barrel .

I wanted to build a separate independent upper assembly around the extra barrel.

My reasoning for building a separate upper around the extra barrel was that I read that removing the barrel from the receiver extension ( that connects the takedown upper to the stock) causes excessive wear on the Barrel threads . I would rather build an extra upper assembly than wear out the threads switching out the TWO barrels.

It would be like having an AR receiver with two separate, individual uppers only a shotgun with one stock and two uppers. One as is with a mod barrel and one built around the extra barrel which is full.

Is this unnecessary? Is it perfectly fine for the threads to just switch between the two barrels I have ?

I apologize if this wasn’t clear in my first post .

[JoyfulJoker]

I don’t have a pic of this with the extra barrel that came with it laying beside it.

[19K]

[JoyfulJoker]

Thank you for answering the question.

I want to buy a take down extension and add the spare barrel , tube etc


Numrich lists that part as the receiver extension , reproduction:

https://www.gunpartscorp.com/products/276790.

Here are a bunch listed on eBay, possibly original , unknown condition : https://www.ebay.com/itm/37424534966...mis&media=COPY.

Would it be wiser to collect the parts and have a knowledge gun smith fit them? Not my expertise.

[dfletcher]

Yes you can and it's not hard. The M12 was designed to be able to take up wear between the extension and receiver.

I did it with my M12 a couple years ago. It went from this with a small amount of play:


To this. I adjusted it so it is now rock solid:

Very nice "trench shotgun". I'm looking for barrel heat shield to do the same on a cutdown JC Higgins Model 20.

[LynnJr]

You would be much better off building it as you have suggested. Push the pin give it a turn and install a complete other barrel assembly.
The barrels fit snugly into the extension and are sometimes hard to remove where as a second assembly can be installed in less than a minute without any tools at all.
Also the adjustments collars are numbered so yes they will wear out with use and you cant skip from a number one to a three or a four you need to go to a number two then three then four. The setscrew that holds the pawl from moving needs to be fully removed to adjust the collar and it doesnt sit flush with the barrel extension.
The pictures show the adjusting collar and the bottom gun shows just what you are asking. If you look I have a ventilated rib barrel assembly placed onto a stripped reciever.
I will have Simmons rib company put a rib on the receiver and when they do that work they reblue the entire shotgun as part of the job.
I will then upgrade the buttstock and have a trap or skeet or hunting gun on the cheap.

[LynnJr]

You would be much better off building it as you have suggested. Push the pin give it a turn and install a complete other barrel assembly.
The barrels fit snugly into the extension and are sometimes hard to remove where as a second assembly can be installed in less than a minute without any tools at all.
Also the adjustments collars are numbered so yes they will wear out with use and you cant skip from a number one to a three or a four you need to go to a number two then three then four. The setscrew that holds the pawl from moving needs to be fully removed to adjust the collar and it doesnt sit flush with the barrel extension.
The pictures show the adjusting collar and the bottom gun shows just what you are asking. If you look I have a ventilated rib barrel assembly placed onto a stripped reciever.
I will have Simmons rib company put a rib on the receiver and when they do that work they reblue the entire shotgun as part of the job.
I will then upgrade the buttstock and have a trap or skeet or hunting gun on the cheap.

[JoyfulJoker]

Thank you!
@ HighPower : that looks outstanding! Trench guns are great.

WRBuchanan : thank you again for sharing your knowledge

@Lynn Junior: thank you for the pics and info. You confirmed what I had thought. Outstanding collection!

Is the bottom shotgun in the picture the one with a new assembly ? I’ll put the Full barrel to good use with a new assembly. Edit * I see the rib on the detail pic.

[2761377]

the part is called Receiver Extension and the one on the gun should be serialized to the receiver. that it is not signals it's a replacement.

to build a new "upper" using the full choke barrel, you need a another plus all the adjustment parts. after you adjust the fit, this assembly may be considered single unit.

then get the mag tube, forend etc.

gl

[19K]

the part is called Receiver Extension and the one on the gun should be serialized to the receiver. that it is not signals it's a replacement.

to build a new "upper" using the full choke barrel, you need a another plus all the adjustment parts. after you adjust the fit, this assembly may be considered single unit.

then get the mag tube, forend etc.

gl