Chamber Polishing tools

[Jetracer013]

Does anyone have a recommendation for the proper tool to use when polishing chambers in both 45ACP and .223? I have several cloth Dremel bits, but I wanted to check to see if there is a better option.

Thank you.

[SoulLessGinger]

The small, felt dremel bit is a perfect fit for the .45 chamber.

I use some flitz and go back and forth a few times at low rpm. Then I turn it off and go back and forth a bunch of times. This keps the grain(?) of the polish in the same direction as the travel of the round.

Good luck, and go easy

[Jetracer013]

Thanks for the tip. The dremel comes with red rouge, is that any good for this?

[Toolguy]

I use red, then green Scotchbrite wrapped around a smaller caliber cleaning brush on a striaght cleaning rod with a cordless drill or drill press. Fast, easy, works great.

[want2race]

The grey polishing wheel that comes with the Dremel, it's about 1 inch diameter (or slightly less), screws onto the shaft. I take those and turn them down to fit the chamber. Works very well, just don't go into the throat. These do remove metal quickly if you are too aggressive with it.

[Ed Robinson]

Flex hones from Brownells are designed for chamber polishing. Have used them for years. search them at brownells. Several grits available from coarse to fine

[BlueOvalBruin]

I would steer clear of polishing rifle chambers. If the case can’t grab onto the chamber wall very effectively it’ll slide and slam into the bolt. For the same reason keep oil out of the chamber.

As for the pistol chambers. It’s very easy to remove a few thousandths of an inch with polishing, so go slow. A few thou is the difference between a match chamber and a glock chamber.

[stiles]

I would steer clear of polishing rifle chambers. If the case can’t grab onto the chamber wall very effectively it’ll slide and slam into the bolt. For the same reason keep oil out of the chamber.

As for the pistol chambers. It’s very easy to remove a few thousandths of an inch with polishing, so go slow. A few thou is the difference between a match chamber and a glock chamber.

This just isn't true. Varmint Al did some FEA showing the difference of a polished chamber and a sand paper rough chamber is only 700 lbs of bolt force but the rough chamber had increased case stretch in the area where case head separation typically occurs. Worse yet a rough finished chamber decreases extraction reliability. I'll take the extra 700 lbs of bolt thrust any day for the increase in reliability and brass longevity.

Have you actually removed a few thousands with an appropriate polishing compound? How long did it take you? I usually use an aluminum oxide in grease compound (555) on a mounted hard felt bob. Aluminum oxide reduces pretty fast, becoming a finer mesh giving less cut, not that 555 has an appreciable amount of cut to begin with. Overheating is a bigger concern than removing too much material in my experience.

I don't like red rouge, it's an iron oxide based polish used mostly for jewelery. I get white 555 compound from Jantz knife making supply house. I'm pretty sure Brownells has it too. If the chamber is really rough you may have to use a more aggressive compound or something like a rubberized abrasive mounted point to remove the tooling marks. Rubberized abrasives are also good at slightly breaking the transitions from the feed ramp into the chamber. The most aggressive I'd use is medium and then move to the fine then to the 555 compound of a hard felt bob.

For a rifle that is on the action I'd do something like Toolguy suggested.

BTW do be careful getting into the throat area. Abrasive compounds don't cut flat surfaces fast at all but they do roll over sharp edges much quicker so stay just back of the headspace plane of a straight wall chamber and you'll be good to go.

If at all possible turn the barrel and counter rotate the polishing tool, or use a stationary polishing tool while turning the barrel. I know it's not the practical unless you have a lathe but it's the best way to do it.

[BlueOvalBruin]

I would steer clear of polishing rifle chambers. If the case can’t grab onto the chamber wall very effectively it’ll slide and slam into the bolt. For the same reason keep oil out of the chamber.

As for the pistol chambers. It’s very easy to remove a few thousandths of an inch with polishing, so go slow. A few thou is the difference between a match chamber and a glock chamber.

This just isn't true. Varmint Al did some FEA showing the difference of a polished chamber and a sand paper rough chamber is only 700 lbs of bolt force but the rough chamber had increased case stretch in the area where case head separation typically occurs. Worse yet a rough finished chamber decreases extraction reliability. I'll take the extra 700 lbs of bolt thrust any day for the increase in reliability and brass longevity.

Have you actually removed a few thousands with an appropriate polishing compound? How long did it take you? I usually use an aluminum oxide in grease compound (555) on a mounted hard felt bob. Aluminum oxide reduces pretty fast, becoming a finer mesh giving less cut, not that 555 has an appreciable amount of cut to begin with. Overheating is a bigger concern than removing too much material in my experience.

I don't like red rouge, it's an iron oxide based polish used mostly for jewelery. I get white 555 compound from Jantz knife making supply house. I'm pretty sure Brownells has it too. If the chamber is really rough you may have to use a more aggressive compound or something like a rubberized abrasive mounted point to remove the tooling marks. Rubberized abrasives are also good at slightly breaking the transitions from the feed ramp into the chamber. The most aggressive I'd use is medium and then move to the fine then to the 555 compound of a hard felt bob.

For a rifle that is on the action I'd do something like Toolguy suggested.

BTW do be careful getting into the throat area. Abrasive compounds don't cut flat surfaces fast at all but they do roll over sharp edges much quicker so stay just back of the headspace plane of a straight wall chamber and you'll be good to go.

If at all possible turn the barrel and counter rotate the polishing tool, or use a stationary polishing tool while turning the barrel. I know it's not the practical unless you have a lathe but it's the best way to do it.

Even if that simulation were valid it means almost a 20% increase in bolt force. It also does not account for the impact of the brass case head slamming into the breach face once it’s slipped off the chamber walls. It’s especially a problem with lower pressure big bore rifle calibers where there’s lots of force pushing back on the bolt but not much pressure to hold the case against the chamber. The fired brass has a ring around the case head from slamming into the bolt face. Usually happens when the chamber is oiled. Brass fired from machine guns with excessive headspace have a similar ring.

For a competition gun which might see tens of thousands of rounds I’d rather not risk breaking bolts, they tend to break at inopportune times. If your gun’s having extraction problems then those problems should be fixed instead of hiding it with chamber polishing.

Yes, I have seen polishing compounds remove too much. I used to work on micro hydraulic cylinders which needed a very fine finish and had a very tight tolerance. Polishing was one of the least effective methods for obtaining our desired surface finish. Very inconsistent and there were far too many variables, even when fixtured. It also removes more material than most final finishing processes.

Do you see any factory gun manufacturers polishing chambers? All the chambers from my personal factory-built guns (Glock, Sig, Springfield, etc.) have very uniform surface finishes that are far from mirror surface finishes, which tells me that there was some engineering behind it. All of my shotguns however do have a relatively fine chamber surface finish.

[tgford58]

To finish a chamber after reaming a wood dowel with 800 to 1500 grit sandpaper glued on like a flapper wheel works. I've used shell casings as lapping tools on rifles. Screw the full lenght resized case to the end of a dowel add super fine lapping compound. Chuck either one into a cordless drill on slow. Be careful, a little goes a long way. Any chamber polishing can make a firearm unsafe in a hurry.

[Jetracer013]

To finish a chamber after reaming a wood dowel with 800 to 1500 grit sandpaper glued on like a flapper wheel works. I've used shell casings as lapping tools on rifles. Screw the full lenght resized case to the end of a dowel add super fine lapping compound. Chuck either one into a cordless drill on slow. Be careful, a little goes a long way. Any chamber polishing can make a firearm unsafe in a hurry.

Thanks for the replies. Out of curiosity, how would polishing make a gun un-safe?

[tgford58]

With a case mouth headspaced cartridge it is important that there is a sharp shoulder for the case to rest on. If that shoulder is chamfered or, in the worst case removed, it is possible for the cartridge to move deeper into the barrel throat. The case cannot properly expand and can result in extremely high pressures. I've repaired guns where the owner tried to polish the chamber and had case ruptures and blown primers. I have never witnessed it but I would imagine the same could happen with a bottleneck case. If the shoulder is moved forward or the angle is changed it seems reasonable that you could cause excessive headspace.

[Rick_L]

Google Cratex guys.

[tgford58]

Why? They have something new?

[BlueOvalBruin]

Google Cratex guys.

Do you have a link?

[392heminut]

Google Cratex guys.

Do you have a link?

Here you go;

http://www.google.com/

then just type in 'cratex' and go!

[tgford58]

Look in Brownells catalog. They sell Craytex bits. If I am not mistaken, Mr. Strader is trying to elude to using a craytex on the chamber. It works very well.

[BlueOvalBruin]

Google Cratex guys.

Do you have a link?

Here you go;

http://www.google.com/

then just type in 'cratex' and go!

That's what I needed, thanks.

[392heminut]

Google Cratex guys.

Do you have a link?

Here you go;

http://www.google.com/

then just type in 'cratex' and go!

That's what I needed, thanks.

Glad to be of service!

[OUshooter]

I've used some 3000 grit sandpaper, local automotive refinishing shop, and lollipop sticks (which came from Hobby Lobby).

Cut a strip of sandpaper ~5/16" wide and 1" long put a piece of tape on it and wrap it around the stick and load that into your cordless drill. It works great.

Edited July 31, 2011 by OUshooter

[tracker]

What are we looking to acieve by polishing? Reliability, brass lasting longer, a larger chamber?

[BlueOvalBruin]

What are we looking to acieve by polishing? Reliability, brass lasting longer, a larger chamber?

I think the thought is that a rough surface finish in the chamber will drag on the bullet as it’s chambered and result in 3-point jams. Plus, extraction is thought to benefit from chamber polishing since the casing will have less to grab on to on the way out. I personally don’t see the benefit in a properly tuned gun but many do.

[tgford58]

Sort of the reason. It is to give a smooth surface to aid in both chambering and extraction. Removing the reamer marks is the point, the effect that it has is a topic of discussion.

[m134b]

I use a worn out chamber brush and JB bore paste mixed with Kroil. 10-15 seconds with a cordless drill on low and you've done PLENTY. That is all a fresh cut chamber needs to smooth out any imperfections that would cause issue. More than that and, as others have said, you could be making a rather expensive mistake.

Ken