View Full Version : How to polish a chamber?

December 17, 2002, 07:28 PM
I have a Savage 23-D in 22 Hornet, with a rough chamber (new brass comes out looking like it has been sandblasted). What is the best way for a handy guy, (but not quite a gunsmith);) to polish its chamber? I was thinking about an appropriate sized bore mop with Flitz on it, spinning in the chamber with an electric drill. Good idea, or bad? Thanx guys-

December 17, 2002, 09:38 PM
I dont think flitz would work good enough and electric drills make me nervous. I would suggest taking a brass case and attaching a rod to the primer hole then take some verrrrry fine grit and attach it to the brass with scotch tape and turn it slowly and evenly checking often intill you have it polished up. Finish up with crocus cloth. Shouldnt take more than a hour or so to do. We do that in our shop here and it usually takes about 15 mins.

George Stringer
December 18, 2002, 07:28 AM
Fatelvis, Nebr_Tom's method is as good as any. Brownells sells flex-hones for different calibers. They work great for chamber polishing. George

December 18, 2002, 02:43 PM
Thanks guys. Wouldnt the "flex-hone" take off too much material though?

George Stringer
December 19, 2002, 06:55 AM
That was my first concern when I read the tip in one of the Gunsmith Kinks books. I chambered a scrap piece of barrel and did a chamber cast, then polished it with the flex hone following the instructions and did another cast. There was no measurable difference. So they have to be used with care and kept moving constantly. But used correctly, no they won't do anything but polish. I only use them on rough chambers that customers bring in for extraction problems but they work well. George

December 19, 2002, 09:17 PM
I affix an empty case to a wooden dowel, cout with Clover medium grit compound , chuck in a variable drill with a "rocker" type trigger. Like George, I fear drills, but if you just rock back and forth , forward , reverse, with out really spinning the drill it works very well.

Its a trick I learned seating heat treated stainless valves in high pressure pumps(>40k.p.s.i.), that saves a little time. Just go real slow, I go 1 minute at a time and check with an inside mic tool.

James K
December 20, 2002, 11:56 PM
It sort of depends, as they say, but the simplest way I have used is to slit a wood dowel and wrap some 600 grit paper around it until it is a close fit to the chamber. Then I chuck the other end in a variable speed hand drill and work the emery paper in and out a few times. (No nasty thoughts, now!) It usually takes only a few seconds. Any finer paper won't be effective and coarser will damage the chamber.

Also you don't want a real mirror polish chamber. The case has to be able to grip the chamber walls when fired. If the chamber walls are too highly polished, the case will not grip enough and the rearward pressure on the bolt lugs will increase.


May 23, 2004, 07:24 AM
...with the bore mop technique, only I used (automotive) valve grinding compound...just a few seconds(maybe 20) in variable speed drill at low speed, with slight(1/2") in and out motion. (This on a sportized military Mauser that was leaving various ridges and marks on brass, slightly tight extraction).Then gotta be careful to remove all traces of compound...Hosed it w/ brake cleaner, swabbed and hosed some more, etc. Seems to have worked well. I don't have a way to measure chamber, but measuring brass before and after firing shows no measurable difference in dimensions, so I can't believe it altered the chamber dimensions significantly. Have some brass that's now been though it 5 times, still looks good.

If yours is really rough, you might need to do it longer...but realize longer is measured in seconds ;)