Sanding the chamber on a shotgun

FLYBYU44

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So I bought a $90 shotgun out of the EE, one of those Sinsinati single shot 12 gauge guns. I actually really like it, it fits me well and I have no problem hitting clays with it. Problem is, certain brands of shells stick in the chamber and will not eject. I have cleaned up the ejector to the point where I am confident it is not the issue anymore. I also polished the crap out of the chamber with very fine steel wool and that helped a lot. However there is still the odd shell that sticks. I know cowboy action shotguns have the chamber loose enough that the fired shells just fall out. Would I be able to sand the chamber with some fine sandpaper and re-polish it, or will that cause issues with pressure in the chamber, I know there must be a spec for chamber dimensions on a 12 gauge. I do shoot 3" magnum shells through it all the time, so obviously I don't want to go to far and make it unsafe to shoot.
 
Polishing the crap out of a chamber with steel wool is simply cleaning the chamber... it would not actually change a chamber dimension.

Polishing a chamber to make it straight and smooth is best left to someone experienced in doing so... it is real easy to simply make it worse...

Sand paper would not be used... 220 grit wet/dry paper would be the coarsest... followed up with 320 wet/dry paper. Oscillating the length of the chamber not staying in one place... spin the barrel in a lathe, spin the polishing rod with a drill...
 
I did it to an svt40 that had a burr or rough spot, spent casing would get stuck hard enough for the extractor to tear a chunk of the rim off. I did the steel wool on the cleaning brush followed by 800 or 1000 grit wet dry paper wrapped around the steel wool on the brush and oil, chucked up the cleaning rod in a drill and did a quick polish. Very quick lol, it completely solved the problem.
 
Polishing the crap out of a chamber with steel wool is simply cleaning the chamber... it would not actually change a chamber dimension.

Polishing a chamber to make it straight and smooth is best left to someone experienced in doing so... it is real easy to simply make it worse...

Sand paper would not be used... 220 grit wet/dry paper would be the coarsest... followed up with 320 wet/dry paper. Oscillating the length of the chamber not staying in one place... spin the barrel in a lathe, spin the polishing rod with a drill...

I chucked a cleaning rod in my drill and wrapped steel wool around it to polish the chamber. I realize that is all I have done so far as I didn't know how safe it would be to proceed with sandpaper/wet/dry.
 
Check ebay for shotgun hone, or look up chamber dimensions and go to local automotive or machine tool supplier. Trick is to keep the hone well lubed and moving back and forth.
 
I am right at the SAAMI specs for the chamber dimensions currently (broke out my telescoping gauge set and micrometer tonight). So I will probably look at getting a stronger spring under the ejector, or see if something is binding there.
 
Some of the promo shells are known to be problematic - Winchesters come to mind. The issue is caused by the use of steel in the base of the cartridge. After firing, the base has expanded and is snug in the chamber due to the properties of steel vs brass. So its not necessarily the gun...
However, if the chamber is slightly rough (think Rem 870 Express), has a lip, etc. then the gun will be prone to sticking shells. FWIW - I have some fairly high end guns that don't like the cheap Winchesters - my solution is to avoid the problem shells.
 
maybe just use the ammo that works in it? You don't feel any taper in it do you?
According to my measurements it is slightly tapered, .815" at the start of the chamber and goes down to .808 near the end. The SAAMI specs are .811 +/- .005 for the start of the chamber and .798 near the forcing cone. My chamber is a little too big near the forcing cone, but meets the spec at the start.
 
Buy a cylinder hone and barrel home along with oil from brownell’s. You can then do it for friends for 30$ to help pay for it. Almost every shotgun will pattern better and function better with this treatment. Also not buying Turkish made crap would also help.
 
Turns out the issue may be a small ridge about halfway down the chamber, I ground that out of there and re-polished it, seems okay now but won't know til I throw some rounds through it. As for the comment about cheap Turkish junk, I agree, but at this stage in my life that is really all I can afford, so I am making it work.
 
Turns out the issue may be a small ridge about halfway down the chamber, I ground that out of there and re-polished it, seems okay now but won't know til I throw some rounds through it. As for the comment about cheap Turkish junk, I agree, but at this stage in my life that is really all I can afford, so I am making it work.
Don't sweat it, modern American junk like the 870 express isn't any better. I used a slightly worn down 1" 120 grit flapwheel and a 6" extension in a cordless drill to polish the chamber. And a carbide burr, a file, some abrasive strips and a lot of swearing to clean up the hideous marks in the receiver. Honestly, there is stuff made in caves that is finished better.
 
My 870 wouldn't eject winchester shells very well. I wrapped 0000 steel wool around a wooden dowel and spun it around in the chamber with a drill. I taped the trigger on the drill so I could leave it for awhile., my previous attempt didn't work and I figured I didn't give it enough . Well ended up falling asleep with it spinning, when I woke up the battery was dead. Immediately took the gun out and it has worked like a charm with winchester ever since.
 
I fail to understand how 0000 steel wool can polish a rough chamber as rubbing it on bluing for a long time has no effect on the bluing...

I think the long use of spinning 0000 steel wool in your chamber cleaned your dirty chamber...
 
The wool is approx same hardness as barrel or softer.... and it is a soft backed abrasive
Eg.. put abrasive compound on a soft cotton cloth and abrasive on a oak wooden dowel ( compare which abrades faster )
The soft back abrasive is way less aggressive

The steel wool just abrades at a very very slow pace if at all.... however it is harder than iron oxide and will remove this
.. another is pumice powder 4f will remove rust ..if used with a soft cotton cloth, wont be too aggressive

Ive done lots of restorations of very old steel n iron objects

What about spraying the chamber with dykem, then using a small dia precision rod try to locate any high spots in the chamber
The idea is just like hand scraping precision flats like on lathe ways.... you just have to figure what exactly is hanging up in the chamber.
 
I would suggest switching ammo before altering chamber geometry. European rims are often cut deeper. Which means when the narrow steel rim of white box fires, the base moves rearward, expands, and grabs like a machine taper.
 
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