How to fix a sticky chamber?

Crazy Chaingun

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Hello all

I've got a Remington Model 12A pump .22 that's giving me some trouble. After firing, I often have to exert an excessive amount of force on the pump to open the action. At times, the extractor loses it's grip on the case and I have to pry the casing out with pliers. I'm suspecting that the root cause of this issue would be friction in the chamber from a burr or something (perhaps from a previous owner dry-firing?).

Any suggestions on how to fix or troubleshoot this? I'd like to do it myself if possible, rather than pay a gunsmith, but I don't want to bugger anything up either.
 
If there is a burr from the firing pin striking the lip of the chamber you will be able to see it. Better to "iron" it out than to file it off.
If you are having to use pliers to get stuck cases out, the problem is more serious than just a fouled chamber.
Do the cases show any roughness? Often the fired cases will reveal the problem.
 
If it really is a slighty rough chamber, some jeweler's rouge or similar polishing compound on a bore swab, turn it for a few seconds with a drill. Don't overdo it.
 
does it matter what ammo you use?
I have a 22lr hand gun that is a bit picky on ammo like that. Some brands are hard to extract.

I had exactly that issue with my Savage when using CCI ammo. I polished the chamber, no more issues. CCI was the only ammo that caused problems, but it's also the most accurate of the cheap ammo (except for Win Subsonic, which is now made from unobtainium).
 
Allright, I scrubbed the chamber with some steel wool to eliminate the possibility of fouling, and did some test shooting.
Extraction is still spotty at best. Sometimes the friction is light enough that I can pry the case out with my thumbnail, but the gun still isn't cycling.

I noticed what appears to be a scratch around the circumference of the case, about halfway along the case length. Upon examining the chamber in the sunlight, I could see what looks like a matching scratch in the chamber. I'm figuring that the problem is either this, or the area of the chamber where the firing pin strikes the case rim.
 
Is it possible that the rifle shot a lot of 22 Short early in it's life? As most was made with corrosive powder, this would affect the chamber and give problems with extraction.
 
Is it possible that the rifle shot a lot of 22 Short early in it's life? As most was made with corrosive powder, this would affect the chamber and give problems with extraction.

Certainly possible, it's an old gun. I only acquired it recently with a purchase of fixer-uppers that I've been selling off, so I have no idea what it was used for earlier in its life.
 
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