Shotgun Forum banner
  • Whether you're a greenhorn or a seasoned veteran, your collection's next piece is at Bass Pro Shops. Shop Now.

    Advertisement
1 - 9 of 9 Posts
G

Guest

·
Discussion starter · #1 ·
Anyone know what year Winchester switched from 2.5" to the now standard 2 3/4" 16 ga shells? Are the receivers of the 2.5" models not compatible with 2 3/4" shells or will the gun work if you replace the 2.5" barrel to a 2 3/4" barrel? Thanks for any info !!!
 
Discussion starter · #4 ·
Switching barrels will not cure the problem. A long forcing cone reamer must be used to lengthen the chamber to 2 3/4", the inside of both ends of the ejection port have to be beveled and part of the ejector must be filed back very carefully to allow the shell to come back far enough to clear the front of the ejection port. I am in gunsmith school and I've done two of these conversions with success. It's easy if you have the tooling and the know-how, but I would recommend finding a gunsmith who has done this before.

Hope this helps.
 
After I picked up an old 16 ga M12 with a 2 ½ inch chamber I did a lot of research on converting the shotgun to 2 ¾ inch and I've found some good information and some misleading stuff.

Actually the 2 ½ inch chamber would be simple to change if that was the only problem. However after the 2 ¾ inch shell is fired the empty will be a problem to eject.

The shotgun I've been working with was built in 1914 and after putting an empty 2 Âľ inch shell in the chamber it doesn't appear that it would be feasible to make it chamber without some machine work. However if you are so inclined Williams Gun Sight Co. lists the conversion in their services section. $170

I don't know the exact date when Winchester changed over to the 2 ¾ but if your shotgun was built prior to 1920 then its probably a 2 ½ inch.

I've decided not to worry about the chambering and am going to use 2 ½ inch 16ga loads from Gamebore in mine. They are an English shot shell loaded to lower pressures but they should work fine in the old M12. They are more expensive than what you'll find at the local wally world and you'll have to special order them. They'll run around $10 a box by the time you get them to your door.

Ballistic Products carries them and has them in stock. There are some others who carry them too but when you order call to make sure they have them in stock as one place I ordered from had them on back order.

I suppose it depends on what you are going to use the shotgun for and how much you are going to shoot it. I'm going to do some hunting with mine, heck it's 90 years old this year, it deserves to go hunting. Also I want to see what the 2 1/2 inch shell is like. I think before converting this one I'd take the $175....$200 by the time you get the shipping in...and buy a later M12 with the 2 3/4 inch chamber. Besides that gives me yet another excuse to buy a gun.
 
1927 was the year winchester announced the longer chamber on their small gauge model 12s. All of the 2 3/4in chambered guns are marked as such with the first 6 or 7 years after the change being marked 2 3/4 on the receiver by the serial number as well as on the barrel.....
 
Discussion starter · #8 ·
gunut 1 said:
1927 was the year winchester announced the longer chamber on their small gauge model 12s. All of the 2 3/4in chambered guns are marked as such with the first 6 or 7 years after the change being marked 2 3/4 on the receiver by the serial number as well as on the barrel.....
Okay the chamber changed in 1927 but was the receiver made longer too to accept the longer shells or is it only the chamber made longer? Can a pre 1927 2.5" gun shoot 2 3/4" shells if the chamber is lengthend or barrel changed to a post 1927 gun?
 
The receiver is the same size but the ejection port is longer on the 2 3/4in guns. That is why they stamped 2 3/4 on the receivers when they first made the change. Some of the short chamber guns will eject some 2 3/4 shells without being lengthened but most will require lengthening to work properly... useing the 2 1/2 inch shells in the older guns is the way to go...
 
1 - 9 of 9 Posts