Polishing rifle chamber

James K said:
Brian, meet Scorch. His experience has been mine also. When someone says "polish the chamber" he may mean Flitz, or 40 grit paper. I have seen chambers so "polished" that the condition did occur or I wouldn't have mentioned it.

Not saying it doesn't happen, I'm saying that it's not "polishing". That's like claiming that taking a submarine to Challenger Deep is "going swimming".
 
I agree that, unless fired brass is deformed, leave the chamber alone or send the rifle back to the factory for service.

If brass is slightly deformed by the scratches, I'd take a fired case, modify the base so it will take a screwdriver shaft chucked in a drill, coat the case with Flitz or JB Bore Paste, then rotate it slowly in the chamber with light force. Such polishing shouldn't be so aggressive as to change chamber dimensions.

In an older rifle whose chamber has rusted, a brass brush with 000 steel wool on a cleaning rod, turned by a drill works well. Too little polishing is better than too much!
 
I'm not polishing!

Don't worry, I'm not polishing (until I get a chance to shoot the rifle and see if extraction works).

But, I am curious -- where does Flitz fall on the grit scale --400, 600, 800, ...?
 
Flitz is extremely fine, finer than rouge or gypsum. It contains talc. So does baby powder, just to give you an idea.
 
I don't think there's any "grit" rating for Flitz. It says "non-abrasive" on the bottle. All it does is turn a smooth finish into a mirror finish.
 
I polish a lot of Rem. auto and pump chambers . I use 000 steel wool on a brass brush for starters , then SimiChrome (Flitz is same thing) on a bore mop . It smooths them up and retards new rust also , the smoother the surface , the less it will rust !
 
Flitz has grit

"I don't think there's any "grit" rating for Flitz. It says "non-abrasive" on the bottle. All it does is turn a smooth finish into a mirror finish. "

I think all "polishing" compounds must have some level of grit in them to make any change to the metal surface. In Flitz's case, it may be very very fine, but it still has to be abrasive (at perhaps some microscopic level) to do anything.

Even water abrades granite over enough time.
 
I'm just quoting what it says on the bottle. No grit rating and it says "Non-abrasive".

It's certainly very, very fine. Two minutes of polishing at 500rpm on mild steel yielded no measurable reduction in diameter of a cylinder for VarmintAl. Measuring a cylinder doubles the measurement because you're polishing and measuring both sides. So even doubling the measurement was undetectable with his micrometers.
 
BTW, I used 320 and finally 400 grit when I polished my chamber. I should add that I chambered the bore myself and that the finishing reamer left marks. This is different from having a finished rifle and deciding that it could use some polishing.
 
100% contact is more contact than 75% contact, I want all the contact I can get. and I want nothing between my chamber and case but air, clean air, air can be compressed, air is fluid, air flows.

Long story, I have a Model 70 Winchester chambered in 300 Winchester Mag, it came with the ugliest chamber I have ever seen, I called Winchester, I explained to them the ugliness of the chamber, in diameter, length and gouges, they instructed me to take the rifle to their warranty smith, I did, he said he was going to hone, polish and or ream the chamber, And I then ask “How will honing, polishing and or reaming going to make the chamber smaller”. Brilliant, his answer was brilliant, he said Winchester said he had to di it. Months later I went to the warranty smith to to check on my rifle, no rifle, I ask why? the warranty smith said the chamber was too large. He sent the rifle back to Winchester, Winchester and I had words, they accused me of of going from being difficult to impossible, I wanted a chamber that fit my dies or I wanted Winchester dies to fit their chamber. It has been 4 years since they returned the rifle ‘in a new box’ one day I will take the rifle to the range.

With all my barrels and not one barrel for a Winchester with a Magnum bolt face.

F. Guffey
 
“Using a bore scope”

If I was using a bore scope I would not be checking for the ‘the cross hatch pattern’.when reaming a chamber the instructions read something like “Do not remove the reamer without rotating the reamer when withdrawing”. So, how did the cross hatch get into cylinder, we know the method for reaming is not back and forth but straight in and straight out while rotating. And then the other question, to cross hatch a tapered cylinder the cross hatch tool would have to have expander springs to force the tool against the taper while making/cutting the cross hatch??

F. Guffey
________________________________________________________________________________________________________________________________________________________________________
The ‘leaver policy’: More times than not I apply the leaver policy, I leaver the way I founder.
 
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Guffey, full length sizing dies' inside dimensions are made to be smaller than rifle chambers. It's not good to have them the same size; if so, fired cases would never be sized smaller.
 
“Guffey, full length sizing dies' inside dimensions are made to be smaller than rifle chambers. It's not good to have them the same size; if so, fired cases would never be sized smaller”

Bart B. I understand and know where that came from, for the benefit of others reading this forum please explain to those that can not distinguish fact from fiction and truth from nonsense the meaning and your motive.

I do not have rifles built, if I want another rifle, I build it. If I do not have a the reamer I have access to 200+, from a total of three friends, I offer them access top 64 reamers. We are all old and doing less, but none of us are starving for attention.

Oneildsap, My presses have threads, my dies have threads, threads on my presses for my dies make my dies adjustable, I do not make wild guestimates as in fractional guesses of a turn or turns in degree converted to thousandths. I use the verifier, I use the feeler gage to verify adjustments in thousandths (.000). Meaning, if I wasted my time guessing when adjusting my dies in fractions and or degree converted to thousandths I would still verify the adjustment, for those that can keep up and have no other motive for arguing when adjusting the die to the shell holder it makes more sense to go straight to the verifying tool, the feeler gage than make a wild guess at the adjustment, then check for accuracy by verifying.

Then there are those that insist on guessing and measuring until ...etc.. For them there is no other way.....because? They insist.

F. Guffey
 
and I said:

100% contact is more contact than 75% contact, I want all the contact I can get. and I want nothing between my chamber and case but air, clean air, air can be compressed, air is fluid, air flows.

If the case was larger than the chamber there would not be room for air between the case and chamber.

F. Guffey
 
I polish a rifle barrel chamber after finish reaming with a brass tip polishing stick with 320 paper like 450 does.
Must have same instructors in school.

For rusting /case sticking I use red/orange diamond paste with oil on a bob/patch.

Or some four o bronze wool
 
I can't imagine a chamber with scratches "barely visible to the naked eye" could cause issues of any kind.

This is the chamber- not the bore/rifling. Seems to my non-gunsmith self that messing with this could accomplish nothing positive with one heck of lot of potential downside.

But hey, there's guys that like to tumble, shine, and polish their brass and primer pockets to microscopic scrutiny...
 
Generally speaking,as cut by the reamer is as geometrically and dimensionally correct as that chamber will be.

If,for whatever reason,the surface finish is not so good,sometimes,maybe,its a reasonable compromise to trade some small amount of dimension or geometric form to gain surface finish.

I would choose the correctness of form over surface finish most of the time.

Best!,use a good sharp reamer and use it right and you will have a very good tool finish.That is a good chamber.

If the tool marks are around the circumferance of the chamber,as they would be from twisting a reamer,you do not polish them out by spinning the barrel and holding some abrasive thing in the chamber.The abrasive will quickly adapt to the lines of the toolmarks,it will cut in the valleys as it cuts the peaks.You will round off and blend,eventually,but what you need to do is cross the texture of the cut...stroke in and out.Then you are only cutting the tops off the peaks.Run the lathe as slow as it will go,or do not run it at all,turn by hand and watch your progress..The stoning lines will run in the direction of the bore,across the toolmarks.If you are running the lathe slow,it will make a crosshatch.Now,once you have stoning lines running in the direction of the bore,then you can switch to a finer grit,spin up the latheand now you will be crossing the stone lines you just made.
 
Pics

Here are pictures of the cases removed from the chamber in question. You can see the scratch lines left on the cases. (These are more easily seen than trying to look fro the scratches in the chamber.)
 

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