Bronze Or Nylon Brush For Cleaning?

[Steve Blair]

Cold-worked phosphor bronze has a yield strength of ~105 ksi. SAE 416 stainless at Rockwell C38 has a yield of ~138 ksi. It is a reasonable bet that the barrel would be damaged.

 

[armorpl8]

<yawn>
OK hydraulics is the transfer of force via pressure. And when excess lube builds up in a die what yields, the brass or the die? The errant bristle must yield to the material of least resistance. What brand of physics is this? I call it common sense. Not the high science some prefer unfortunately.
I have witnessed tiny slivers of copper emerge on a patch where a brush was never used. Copper fouling does not always lay down in a uniform pattern in a barrel. Some barrels foul more than others and some foul hardly at all. Uniform for a particular barrel? Maybe. But the oportunity exists for a tiny sliver of guilding metal to be caught by the next bullet at any given time.
Cleaning methods can be argued forever and a day. There are many correct ways to clean a barrel and many bad ways to clean a barrel. Almost all involve running a final patch down the barrel, maybe several final patches, as has been so well illustrated by the last few posts. I have used both nylon and bronze to clean barrels and continue to do so without fear. I patch the bore liberally after running any brush and use a Sinclair bore guide. My point in responding to this post was to confound the notion that there is any danger in properly brushing a bore. I don't need to be a physicist to prove that fact. Clean your barrel any way you see fit and lay awake at night wondering about that tiny bronze bristle it matters not to me. If John or Leonard have seen evidence of what you claim then by all means educate us all. Till then I will remain a happy idiot.
What is the yield strength of gilding metal....gimme a break, does the bullet play no part in this equation. We are assuming the bullet is causing this conundrum.

 

[Steve Blair]

What is the yield strength of gilding metal....gimme a break, does the bullet play no part in this equation. We are assuming the bullet is causing this conundrum.

Gilding metal yield strength in the cold-worked condition is ~50 ksi. Certainly, the bullet is a factor. The shape of most bullets are such that they act as a wedge, providing significant lateral mechanical advantage. Even with a .218/.224 bore, there can be up to 2000 pounds force pushing the bullet. At typical in-bore velocities, the barrel is likely to suffer damage. It is just a good idea to make reasonably certain that no bore obstructions exist before firing. Stainless barrels, especially, are not particularly hard.

FWIW, I use both bronze and nylon brushes and try to pay attention to copper and carbon accumulation. A good borescope is a worthwhile purchase to track your barrel condition. I usually scope the bore after every shooting session. It only takes a few minutes and is worth the effort.

I saw some damage that I cannot explain after purchasing a used rifle. The factory Remington barrel had a diagonal mark across one land, about four inches forward of the chamber, extending into the two adjacent grooves. It appeared slightly deeper on the land. Whether this occurred at the factory or during firing, I do not know. It has since been rebarreled but I wondered then whether it was caused by something left in the bore.

 

[jo191145]

Who would build a custom gun or buy a factory target rifle and not buy a bore guide before cleaning it the first time? I always follow the bronze or nylon brushing with several patches. I have seen brush particles on the first patch several times. That is why I patch until there is nothing on the patches. Later! Frank

Sure seems like Frank has the right answer

Heres a theory. Would'nt the atmospheric pressure in front of the bullet push that little scrap of bronze out in front of the bullet? Perhaps if it was close to the throat the bullet might overtake it.
Good question for you scientific types.
Clean the barrel properly and its a nonissue.

 

[Forum Boss]

No need to fight over this one folks. Steel is harder than copper/bronze, yes, but as John Krieger explains, the bronze bristles hold a lot of other gritty stuff that causes wear. If you look at a barrel with a 8-10x magnifier, and look at a crown that has had a lot of back and forth bronze brushing you'll see the edge of the crown has acquired a sawtooth edge. Tim North of Broughton explains that as the bristles are forced to reverse themselves at the muzzle, the bristles are like little spikes that can make tiny cuts and striations in the metal.

Look at steel under magnification and you'll see that it is NOT a flat uniform surface, like the way we perceive glass to be. In fact there are flakes and ridges which can be worn down or chipped.

The real answer to bronze vs. nylon is do what the barrel needs... and no more. Most barrels shoot best when they are relatively new (under 200 rounds). Therefore your cleaning practice should be "minimally invasive" with the goal of keeping the barrel in near-new condition. Some barrels need much more aggressive cleaning than others. I have a PacNor 3-groove that has never seen a brush of ANY kind in 700 rounds and it shoots as good as new. I had a factory Savage barrel on it before that needed multiple applications of sweets and aggressive brushing to clean up.

I suggest that, if you do use a bronze brush, remove it at the end of the "out" stroke and clean it off with solvent before the next pass.

 

[boogershooter]

Boy, I bet your sorry you asked! I invert the gun and use a fast evaporate degreaser like quick scrub at end of procedure. Then, if in my garage blow air through barrel with compressor hose to remove ,and dry out. Lastly, a dry patch followed by a lube patch,something that wont etch the barrel. Just one more method. Dont forget to lube lugs / bolt! Good Shootin Brother!

 

[Walt_NC]

OK hydraulics is the transfer of force via pressure. And when excess lube builds up in a die what yields, the brass or the die?

When excess lube builds up in a die, the brass case is the first to yield because it is hollow. Replace the standard case with one of solid brass, apply lube or a copper bristle to the inside of the die (anything that will create a focused pressure point) and slam that solid case in at 2800 fps, propelled by gases expanding at 60,000 psi. Even though the case will take the brunt of the damage, it remains quite possible that the die will be damaged as well.

What brand of physics is this? I call it common sense. Not the high science some prefer unfortunately.

In this case "common sense" is nothing more than your belief; one that you are unable to support. I find your dismissal of physics as "high science" curious considering you were the first one to demand the use of physics to support an argument.

I have witnessed tiny slivers of copper emerge on a patch where a brush was never used. Copper fouling does not always lay down in a uniform pattern in a barrel. Some barrels foul more than others and some foul hardly at all. Uniform for a particular barrel? Maybe. But the oportunity exists for a tiny sliver of guilding metal to be caught by the next bullet at any given time.

Whether copper fouling is precisely uniform is irrelevant. The issue to consider is the amount of copper fouling deposited and the location it is deposited in. Copper fouling is more or less evenly distributed along the entire length of a barrel. The amount of reside left behind after a normal shooting session is so minute that it is largely insignificant. If you take all of that copper residue and stack it 0.001" (the width of a copper bristle) high in a single spot and nowhere else, then it becomes significant.

My point in responding to this post was to confound the notion that there is any danger in properly brushing a bore. I don't need to be a physicist to prove that fact.

You don't need to be a physicist, but to state your opinion as fact requires you to support it. It's called the "burden of proof". Otherwise you are committing a logical fallacy known as an appeal to ignorance. I am by no means a physicist or a metallurgist so there may be faults in my reasoning. I acknowledge this and so remain open to folks who can support a conclusion that contradicts mine. As it stands, I have offered something to support my reasoning. You have not.

Clean your barrel any way you see fit and lay awake at night wondering about that tiny bronze bristle it matters not to me. If John or Leonard have seen evidence of what you claim then by all means educate us all. Till then I will remain a happy idiot.

When I spoke with John, he did not offer evidence, nor did I think to ask for it. John simply said it a copper bristle left in a barrel is bad news. The theory as to why this is so is mine alone; I do not speak for anyone but myself. If you are curious as to how John came to his conclusion, there is nothing stopping you from giving him a call at the shop @ 336-667-8785.

What is the yield strength of gilding metal....gimme a break, does the bullet play no part in this equation. We are assuming the bullet is causing this conundrum.

I'm not sure what you are asking/stating here. The bullet is not the key factor in this scenario. The force behind it is.

 

[Walt_NC]

Heres a theory. Would'nt the atmospheric pressure in front of the bullet push that little scrap of bronze out in front of the bullet? Perhaps if it was close to the throat the bullet might overtake it.

Thats a great question, one that I will definitely ask a my prof. Shooting from the hip here, I would guess that the atmospheric pressure created by the bullet would be kind of like a car @ 60 mph driving over leaves in the road. The leaves aren't pushed in an opposite direction (directly away) from the car as much as they are displaced and pushed to the side.

 

[Steve Blair]

A precursor wave results from bore gases compressed ahead of the bullet as it travels down the bore, sometimes reaching 5 ksi at the muzzle. It would likely move anything dry and light weight. If a bronze bristle was stuck to the barrel by solvent or was just laying in the bore, it might not be enough to overcome either fluid adhesion and bristle inertia before the bullet arrived. Best just to make sure that it is not there.

 

[rogn]

Re: Bronze Or Nylon Brush For Cleaning? DEMO

Lets try a different approach, simply take a new bronze brush and find a nice shiny SS barrel. Choose a spot on the outside of the barrel and either wet or dry proceede to scrub it vigorously with the brush. Wipe dry and examine with a good magnifier. You will most likely find very fine scratches on the barrel more so if it was highly polished to start with. Draw any conclusions you care from this little demo.

 

[Forum Boss]

Re: Bronze Or Nylon Brush For Cleaning? DEMO

Lets try a different approach, simply take a new bronze brush and find a nice shiny SS barrel. Choose a spot on the outside of the barrel and either wet or dry proceede to scrub it vigorously with the brush. Wipe dry and examine with a good magnifier. You will most likely find very fine scratches on the barrel more so if it was highly polished to start with. Draw any conclusions you care from this little demo.

I have to admit, with embarrassment, that I did this test (by accident) a few years back... but on the sideplate of a stainless Smith & Wesson revolver m617. The bronze brush very definitely left visible scratches all over the sideplate. Scratches easily visible to the naked eye. And I tried my hardest to then polish them out without much success.

To do your own test, try running a bronze brush over the sides of a stainless cooking pan or pot... you may be surprised.