Winchester Mod. 12 problems

[mod31]

Have a Winchester model 12 made in 1923. Had chamber lengthened to 2 3/4 but was told did not need to enlarge ejection port for reliable cycling. It sometimes jams and loaded shell will not enter chamber. While I don't think this has to do with ejection port it's one of my problems.

The other problem is the slide release "button" at back of trigger guard will usually not release slide no matter how hard I push on it. I often have to turn the gun over and use thumb pressure along with forward pressure on forearm to get the slide to release and come back.

Is it difficult to get the slide release to function as it should?
Does the ejection port need lengthening?
Why does loaded shell jam after shooting shell in chamber and cycling action to get next round in chamber?

I know you need to work the action of a pump shotgun with gusto, which I do.

I also have a model 31 Remington and there's a good chance it'll be my favorite pump. May also buy model 870 Remington and model 37 Ithaca to determine in my mind which really is the greatest pump shotgun. Reliability is number 1.

Mod31

 

[gunut]

you have to push the slide release and push forward on the forend and it will release.....all 12ga model 12s were at least 2 3/4in from the start of production ....the 16ga and 20ga were short chambered until around 27 or so......and most of the time you have to alter the ejection port along with lengthening the chamber....more so on the 16ga for some reason....

 

[birdshot8's]

^^^ What Gunut said: ^^^

When firing recoil moves the the gun to the rear, the slide gets left behind, allowing you to pull the slide back to eject the shell. If you did not fire the gun and wish to release the slide you have to nudge it forward, before pulling back. Some model 12s won't need the forward push indicating parts wear. Yours sounds like it is working as designed. Fire a round without touching the slide. Your M12 should eject the hull on its own.

 

[FL-NC]

Winchester 12's are weird that way with the slide IME.

 

[Crawdad1]

You increased the chamber length but not the ejection port and you're wondering why it jams? What gauge? I had problems with my 16 gauge Mod 12 jamming through the ejection port. The button on the back of the trigger guard should release the slide and it sounds like it just needs a good cleaning.

 

[mod31]

Thanks for all of your replies.

I was told by the guy who reamed the chamber to 2 3/4" that the ejection port does not need to be lengthened. But, I've read it does.

Of course the ejection port has nothing to do with why it sometimes jams when trying to get loaded shell into chamber. On second shot attempt after firing first shell.

I should be able to use the side of my trigger finger (right handed) to push slide release button but--as I said--I often have to turn gun upside down and use my right thumb to apply even more pressure to button. And yes, I push forward on corn cob forearm at the same time.

The slide releases fine after firing a shell. It's the initial attempt to chamber the first shell when I have to fight the slide release button.

Believe I read that the "fix" for a faulty slide release on the model 12 can be difficult and done incorrectly by most people/gunsmiths.

mod31

 

[entropy]

Winchester 12's are weird that way with the slide IME.

No, many pumps from that era do that; Remington Models 10 and 29, Ithaca 37, (based on the Rem. 10 and 29) Savage Models 520 and 620 come to mind. There are probably more.
As Crawdad suggests, I'd pull the trigger group and detail it and the receiver wall where the slide release rides.