Winchester Model 12, Strange jamming issues

[BigDotGlock]

I'm kind of stumped, so I figured I'd ask you sirs about a weird problem I'm having with my Model 12.

It works flawlessly with birdshot, it'll even "slamfire" without issues, but it hates buckshot. Anyime I try firing buckshot I get off the first shot and the action locks up, to the point I have to hold it by the forend and slam the butt on a solid surface.

It has nothing to do with recoil or the power of the loads. I can put an empty birdshot hull in the chamber, close it, eject without issues. Even an empty buckshot hull jams up the works.

I'm thinking it has to do with the length of the brass base on the buckshot messing with the chamber...make sense? If that's the issue, can it be fixed?

 

[M12shooter]

That old M12 has never had any Imperial Long Range ammo shot through her? I think it's more an issue with the ammo. I would bet its a pretty heavy payload of shot and the steel bases on those loads.

I know my trap M12 has trouble with those Federal cheapo promo loads with the shiny steel bases. They stick a wee bit upon extraction. Not smooth like STS Remmie stuff. Got to remember the M12 was designed when shot shell heads were made from real brass.

Another possible would be a bur inside the chamber. Might have been that way from the factory as after WWII Winchester was turning out shotguns like there was no tomorrow! Break the gun down and inspect the chamber with a light and feel with your finger.

Just remember those 1 1/2 oz. magnum shells will rattle apart a M12 in time...especially if ya slam fire the thing on a regular basis.

 

[bigeasy]

2 3/4 inch chamber? 3 inch slugs?

 

[BigDotGlock]

I wouldn't risk 3" shells, it was made in 1914, I was originally worried it had a 2 5/8" chamber but 2 3/4" birdshot are fine. I only tried the slamfire for a few rounds, for the novelty of it, got old fast.

I'll take it appart and give it a good look this weekend. It's a neat old gun, I'd like to keep it in good running order.

 

[M12shooter]

Are you giving the for end a slight push forward after firing...dumb question I know but I've seen Model 12 novices pulling back on the pump and swearing as the ducks peel away. Also a 1914 M12 would be of nickel steel...not as strong as the newer proof steel.

 

[BigDotGlock]

I gave it a good inspection, no burrs in the chamber. I wasn't aware of the difference between nickel steel and proof steel, thank you for that.

I guess I'll just take it easy on the old girl and content myself with shooting birdshot, leave the heavier stuff for her safemates.

 

[gallen270]

buckshot is generally loaded to a higher velocity...more pressure. if it has a high base, thats more surface area to expand in the chamber after being fired and could be creating more friction then say a cheap federal load with low brass.

when you put a fired bickshot in, is it tight entering the chamber?

if you have a micrometer, also measure rim thickness's to see if there a big difference between brands.

 

[BigDotGlock]

buckshot is generally loaded to a higher velocity...more pressure. if it has a high base, thats more surface area to expand in the chamber after being fired and could be creating more friction then say a cheap federal load with low brass.

when you put a fired bickshot in, is it tight entering the chamber?

if you have a micrometer, also measure rim thickness's to see if there a big difference between brands.

I don't notice the spent hull being tight entering the chamber, I'll get my hands on a micrometer sometime and figure that out.

 

[catnthehatt]

I don't notice the spent hull being tight entering the chamber, I'll get my hands on a micrometer sometime and figure that out.

Yup, i'd check the high brass expansion as compared to the low.
And as was stated the pressures will be higher on the slugs....
Cat