Barrel Cleaning: A Discovery

[jelenko]

Hmmm. I've got a couple of new, never fired stainless barrels. I'm going to try brushing the bores.

New, never installed or fired barrel.
First ran three dry patches through the bore to remove the oil [as a preservative].
Ran one clean patch through with C4 - nothing on the patch.
Cycled brass brush with C4 five cycles. Ran clean, dry patch through - lots of gray stuff

Cleaned a section of the outside of the barrel with MPro 7. Dried off with clean white patch - nothing came off.
Rubbed bronze wool with C4 on the same section - obvious areas of grey stuff.

My conclusion: Rubbing bronze on stainless steel produces grey stuff. Enough rubbing it will produce lots of grey stuff which gets darker with more stuff.

 

[Gargoyle]

New, never installed or fired barrel.
First ran three dry patches through the bore to remove the oil [as a preservative].
Ran one clean patch through with C4 - nothing on the patch.
Cycled brass brush with C4 five cycles. Ran clean, dry patch through - lots of gray stuff
View attachment 1391577
Cleaned a section of the outside of the barrel with MPro 7. Dried off with clean white patch - nothing came off.
Rubbed bronze wool with C4 on the same section - obvious areas of grey stuff.
View attachment 1391578
My conclusion: Rubbing bronze on stainless steel produces grey stuff. Enough rubbing it will produce lots of grey stuff which gets darker with more stuff.

This is what's happening with me. Thanks for reporting!

 

[jelenko]

This is what's happening with me. Thanks for reporting!

You're welcome.

At the same time, the pics of your bore show the middle of the grooves much lighter color than the parts of the groove next to the land. You were wondering if the darker color was the unworn nitride finish.

FWIW, that is probably not the nitride finish. My understanding is nitriding penetrates several thousandths into the surface => unlikely that there is that much wear.

To check, just use Iosso/KG 2/Flitz bore cleaner on a tight fitting patch wrapped around a parker hale jag. Do 10 passes; replace the patch with new abrasive four times.
Cleanout with bore solvent, dry patch; check with borescope.
If it's carbon, you'll see a lot less of it and the center light colored area will be much wider.

 

[Newhouse]

My 2 cents.
Steel is harder than the bronze brush material. As you rub the bronze bristle on the steel surface, the bronze bristles wears out leaving material on the surface of the steel. This material is what you would be getting when wiping out with clean patches. Even though the steel appears smooth, it has some roughness to it that is not visible to the naked eye.
Bronze and brass material are use for bushings or bearings so that the major part does not wear out.

 

[Gargoyle]

You're welcome.

At the same time, the pics of your bore show the middle of the grooves much lighter color than the parts of the groove next to the land. You were wondering if the darker color was the unworn nitride finish.

FWIW, that is probably not the nitride finish. My understanding is nitriding penetrates several thousandths into the surface => unlikely that there is that much wear.

To check, just use Iosso/KG 2/Flitz bore cleaner on a tight fitting patch wrapped around a parker hale jag. Do 10 passes; replace the patch with new abrasive four times.
Cleanout with bore solvent, dry patch; check with borescope.
If it's carbon, you'll see a lot less of it and the center light colored area will be much wider.

Everything I have that is nitrided is a very smooth, deep gloss black. Hence why I was/am in a state of question. LOL. Gonna see if LGS has the IOSSO, JB and see what happens!

 

[Gargoyle]

With the bronze brush mystery solved it’s time to see what comes out of the 416R Wilson Combat 7-08 barrel after a few hour soak with FreeAll.


After 3 hour soak: Patched clean

Then 10 passes with new bronze brush/clean rod/clean chamber, clean barrel. 1st wet patch:

Where carbon ring builds up:

 

[Dusty Stevens]

Why not use actual bore cleaner? Are you just trying to see if you can get it to work like these CLR threads?

 

[jelenko]

I agree with Dusty.
I've experimented with Free All a bunch.
No question is does work on hard carbon - but really, really, really slowly. Just brushing and soaking hard carbon with Free All is going to take several days of repeated brushings, soaking, waiting. I gave up after 3 days with 8-12 hours between brushings. After each wait period, I patched it out and looked with a borescope. That's how I could tell it was going slowly cubed.

Using an 'abrasive' allows you to actually make visible progress. Using a borescope enables you to see how it's going and when it's enough.

I've found KG2 and Flitz bore cleaner to work the best. Iosso works about the same but I find the more liquid ones to be easier to work with.

JB works absolutely the slowest. It does work, just takes over twice as much effort. A plus for JB is that there's no lube needed to get a tight patch into the bore.

 

[Gargoyle]

Why not use actual bore cleaner? Are you just trying to see if you can get it to work like these CLR threads?

It was time to switch it up.