Chamber Polishing

mdwest · Nov 4, 2025

Ive got a rifle with a pretty fouled chamber that could also likely benefit from a little polishing..

Whats everyones favorite method and product for said task?

Ive seen a lot of guys use wooden dowels inserted into a drill, wrapped with a super fine sandpaper (800 grit or even finer).. but.. I think thats a bit too aggressive for me..

All Ive done in the past is use a brass chamber brush chucked up in a drill, soaked in a decent solvent.. that seems to do the trick for getting any/all fouling out.. but falls pretty short on the polishing side of the house..

Ive thought about something that might be "middle ground"... still using the chamber brush and the drill.. but maybe using a light application of something like flitz...

thoughts?

jnmullins · Nov 4, 2025

I used a fine grit Flex Hone to remove a few small defects in the chamber of my 7 SAUM that were leaving scratches on the brass and it worked very well. I think I got it from either Brownells or Midway. Glitz or Iosso should also work with less risk

TnKen · Nov 4, 2025

I've never polished the chamber of a rifle but do my turkey shotgun barrels. I use green scotch brite pads wrapped around a bore brush and chucked into a drill. I also use a little lubricant on it.

deewayne2003 · Nov 4, 2025

I would use the bronze brush and Flitz

BlueFlyer · Nov 4, 2025

You need to be very careful polishing the chamber. The case needs to grip the chamber when it is fired. If the chamber is polished too much, the back thrust will increase and possibly damage the breach mechanism over time. I have seen a Sako 461 where the bolt locking lugs had imprinted on the breach locking faces due to the chamber having a mirror polish.
If you can fire the rifle and the case extracts OK then I would leave it be. If you are having problems with extraction, then use a fired case as a lap with some fine automotive valve grinding compound as the cutting medium. Do the bare minimum.

Denvir Tire · Nov 4, 2025

BlueFlyer said:
You need to be very careful polishing the chamber. The case needs to grip the chamber when it is fired. If the chamber is polished too much, the back thrust will increase and possibly damage the breach mechanism over time. I have seen a Sako 461 where the bolt locking lugs had imprinted on the breach locking faces due to the chamber having a mirror polish.
If you can fire the rifle and the case extracts OK then I would leave it be. If you are having problems with extraction, then use a fired case as a lap with some fine automotive valve grinding compound as the cutting medium. Do the bare minimum.

This is very good advice, BUT, any valve grinding abrasive compounds, available "over the counter", will be much too coarse for what you're trying to accomplish. Try using a gentle abrasive such as buffing compound for auto paint.

Red Leg · Nov 4, 2025

Is it an appearance issue or an actual problem with stuck cases and the like?

BlueFlyer · Nov 4, 2025

Denvir Tire said:
buffing compound for auto paint.

Sorry but I disagree on buffing compound as it is intended to create a highly polished surface which risks creating a mirror type surface.
The chamber MUST grip the case when it fires. If you can get some 120grit compound that would be better than fine valve grinding paste but not as easy to source. If the chamber needs more than a quick lap, then it really needs to be rechambered with a reamer.

Grumpy gumpy · Nov 4, 2025

I’ve used 180 grit lapidary paste on a bore mop in a drill to polish a rusty looking chamber , few quick zigzags to clean and then a really good flush out, inspect and repeat.
Gumpy

Stompbox · Nov 5, 2025

After I finish chambering a barrel, I wrapped 600 grit around a dowel and run. It back-and-forth to create a light cross hatch pattern. For what you wanna do, I might start with putting some steel wool around a brush and running it in there a little bit first to see if it cleans it out, you’ll want to have some oil on the steel wool when you do it. You would have to get pretty aggressive to do any damage, just try not to run it up into the rifling.

rdog · Nov 13, 2025

Get a 8mm wood dowel about 200 mm long, cut a slot in one end 30 mm long with a hack saw, wrap some 400 grit emery cloth around the dowel with one end of the cloth in the slot to just under case diameter oil up the cloth , run in a cordless drill to polish chamber at low speed DO NOT over do it. AS BLUE FLYER SAID A 400 GRIT FINISH IS ALL YOU NEED.

Bob Nelson 35Whelen · Nov 19, 2025

mdwest said:
Ive got a rifle with a pretty fouled chamber that could also likely benefit from a little polishing..

Whats everyones favorite method and product for said task?

Ive seen a lot of guys use wooden dowels inserted into a drill, wrapped with a super fine sandpaper (800 grit or even finer).. but.. I think thats a bit too aggressive for me..

All Ive done in the past is use a brass chamber brush chucked up in a drill, soaked in a decent solvent.. that seems to do the trick for getting any/all fouling out.. but falls pretty short on the polishing side of the house..

Ive thought about something that might be "middle ground"... still using the chamber brush and the drill.. but maybe using a light application of something like flitz...

thoughts?

@mdwest
I use a bronze brush wrapped with 0000 steel wool sprayed with inox or wd40.
Bob

Chamber Polishing

mdwest

jnmullins

TnKen

deewayne2003

BlueFlyer

Denvir Tire

Red Leg

BlueFlyer

Grumpy gumpy

Stompbox

rdog

Bob Nelson 35Whelen

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