Ridge in rifle chamber

[Northwoodneil]

Hi long time lurker first time poster, I recently purchased a Winchester 1885 in 32-40. It had the barrel relined and looks like a professional job. Upon trying to chamber a round they fit really tight and didn't want to extract. I coated the cartridge with Dykem and when a shell was chambered and knocked out of the chamber it has a bright ring 1/4 inch from the rim. The Dykem left a corresponding ring in the chamber. The ridge is maybe a few thou. high. It's like who ever chambered the rifle had a chip in their reamer. Can I lap that out with an abrasive (like valve compound) coated empty casing (cut off just past the ridge so I won't mess with the rest of the chamber) or do I have to rent a reamer?

 

[john.k]

Yes ,fit a 1/4 rod into the base of a case ,split the case into four fingers ,embed some 400 grit into the brass ,was off excess ,and hone with kerosene as wetting agent..........obviously the base is a bad spot to enlarge ,but needs must ...........I assume you relined to preserve the originality,so wont want to set the barrel back ..........In a 32/40 ,a slightly larger case like 303 may make a better hone.

 

[john.k]

PS a reamer wont get you anywhere ,unless you rechamber for a bigger base ,say 30/40 Krag or 303 .....neither of which have a 320 bore.

 

[Northwoodneil]

Thanks John. I made a lap from a 32-40 case filled with cerosafe. I turned the rim off of it and center drilled and tapped it to fit on an old cleaning rod. By removing the rim I won't deepen the rim recess by accident changing the headspace. I shortened the case to go past the ridge by about 1/8 inch. I haven't tried it yet, I wanted to hear what the metal magicians said first. I was thinking a fresh reamer would clean up the ridge but didn't want to pull the barrel.

 

[john.k]

In general ,to lap a conical bore (your chamber) you must have a spring lap ,that will produce a crosshatch pattern.........if you attempt to use a solid lap ,you will groove the surface .......to make a spring lap ,split the case into four and lever the fingers out a bit .....charge this with grit and use kerosine .....if you lap dry ,the lap will 'blind ' and score the chamber.

 

[Northwoodneil]

Got it, thanks

 

[FredC]

PS a reamer wont get you anywhere ,unless you rechamber for a bigger base ,say 30/40 Krag or 303 .....neither of which have a 320 bore.

Curious why a reamer would not work. I built a 35/40 and the reamer manufacturer made it too small just ahead of the rim. I sent the reamer back 2 years later with sample cases. They acknowledged their mistake made the new reamer. I made a thin brass disk to ride on the reamer to keep from deepening the rim recess and changing the headspace. I made an extended driver and reamed though the receiver. It turned with a little resistance till the brass spacer touched the barrel, then spun freely. The cases fit now and the spent cases extract easily.
This was done years ago, but I think I see the brass washer in the chamber before I cleaned it out.

 

[john.k]

I m interpreting the OP as saying the chamber has an imperfection caused by a chip stuck in a reamer ...which I would think was a groove .....not a raised area..........Now you would think I would learn not to offer opinions on things I have not seen .....

 

[FredC]

I m interpreting the OP as saying the chamber has an imperfection caused by a chip stuck in a reamer ...which I would think was a groove .....not a raised area..........Now you would think I would learn not to offer opinions on things I have not seen .....

Well, it is not like I never misinterpreted an OP's question.

Nah, I have never done that more than once a day.

If the OP did indeed have a groove in the chamber wall, your answer makes sence. Since this has come up the OP might run a smooth probe along the chamber wall to verify which way it is. I hate the idea of having to clean lapping compound out of an action, the stuff kind of gets everywhere.

 

[cyanidekid]

I m interpreting the OP as saying the chamber has an imperfection caused by a chip stuck in a reamer ...which I would think was a groove .....not a raised area..........Now you would think I would learn not to offer opinions on things I have not seen .....

haha! well that would put you in the minority here by a wide margin...

 

[Northwoodneil]

Well my lap worked for me!! The lapping compound took a lot of size off my lap as I worked it which I think worked in my favor by letting me move into the chamber farther eliminating any ledge. I started with coarse compound for a short time and this roughed up the lap to hold the fine compound really well. I made another 1/2 chamber length lap and did a final polish with simichrome paste. Clean up wasn't to bad I cleaned up the big stuff and let the ultrasonic cleaner get rid of the rest. Thanks all. Neil