Winchester Model 12 chamber conversion

Brad F

Because I had never owned a Model 12 I recently I picked up a "Heavy Duck" and shot it at the end of the last duck season with some Bismuth. Great gun and fun to shoot.

My question is about the difficulty of converting 2 3/4 inch chambered guns to handle 3 inch ammo. I've had Rem 870 converted and the only thing to do besides using the 3" chambered barrel was replacing the ejector in the receiver for the 3 inch part. According to the Model 12 book by Madis, Winchester and many gunsmiths lengthened the short chamber to 3 inch routinely. Is there more to converting the short chambered Model 12 guns to handle 3 inch shells than lengthening the chamber?

There are so many more 2 3/4 inch Model 12's on the market and I'd like to pick up another shooter for field use. Since I use 3 inch ammo in some of my hunting guns I try not to have 2 3/4 inch guns for field use to prevent the possible problems with shooting a 3 inch shell by mistake.

Any info or experience on this conversion would be appreciated.

bobski

welcome to the boards![:)]
im not an expert but just off the top of my head i see a bolt length issue, the forearm slide stroke issue, shell carrier, and a loading port issue.

only winchesters

Hello Brad: Winchester converted many short chambered 20 & 15ga. guns to 2 3/4 inches. for a very short time, they offered to convert a standard Md 12 (2 3/4) to 3 in. this practice stopped very soon, it just wasn't cost effective.

Parts unique to the 3 in Duck:
Barrel, Mag band and bushing, Action slide,barrel chamber ring, trigger guard housing, breech bolt,carrier, ejector, and butt stock.

If you were to find all these parts they would cost you more than a Duck Gun!

The factory conversions, didn't hold up well, simply because the receiver on the 2 3/4 was machined for the 2 3/4 trigger guard housing. The duck trigger guard housing is machined shorter, thus allowing for the modified Duck carrier, as well as a Duck bolt is machined slightly different, and they take a special barrel chamber ring so the bolt sets back farther.

cost of all the parts and a gunsmith with the knowledge to do the job, you could buy 2 complete duck guns, in the 75-85% condition.

Regards Dave

Brad F

Thanks for the info.

I understand that the actions are unique and that many of the "Heavy Duck" parts are not interchangeable with the "standard" actions. I had been told, 3rd hand unfortunately, of a fellow that has had several 2 3/4 inch Model 12's adapted so they would function with 3 inch ammo. I guess I better start running down this 3rd party and see where the story breaks down. I just discovered this forum and thought I'd ask the question but I suppose I better stop by the Gunsmth that I have used in the past and run this by him also. Thanks again for you time to answer the question.

I suppose I could have the chamber lengthened so that a 3 inch round would not produce terrible over pressure if inadvertently fired in the "standard" gun even if it caused a malfunction of the gun. I won't be hunting dangerous game with this for sure so a stoppage would only cause a slow down of my gunning efforts in the duck blind.

bobski

the thing that makes the M12 3" mod tuff is, anyone can lengthen a bbl to accept a 3" hull. its getting it to feed and eject thats the problem. im with OW on this one. the cost doesnt make it worth it. you could buy a whole new gun for the cost. avoid this classic bag of worms.

only winchesters

My only comment Brad, if you find a "Gunsmith" who will open up the chamber to 3 in. Make sure he has a good Liability Insurance Policy!! You may need it! What you don't know is the 2 3/4 in. Mag beats a standard Md 12 to death over time. A 3in. Mag will do it in a hurry.

Regards Dave

Brad F

Thanks again for the comments.