Is leading galling?

[subsonic]

http://en.m.wikipedia.org/wiki/Galling

There is the wiki on galling. I always take wiki with a grain, and suggest others to do the same, but this seams reasonable.

If leadins IS galling, maybe the same things that prevent galling can prevent leading?

Maybe a smooth bore really ISN'T what we want? Maybe firelapping cuts places for lubricant to reside? Maybe very minor bore pitting does the same?

[MtGun44]

Galling is a cold microwelding process with the same metal when they are not protected by an
oxide layer. I have never heard the term appliedto dissimilar metals. SS can gall with SS and
aluminum can gall to aluminum very badly if neither piece is anodized.

Bill

[dubber123]

The bore on my 1895CB looked like an old set of railroad tracks when I got it. After firelapping it looks like a mirror. I can load a full 3 grains more of powder before leading occurs, with a substantial increase in velocity before it occurs. The rough bored 32 Wcf revolver I firelapped responded similarly. In these cases, the smoother bores definatly helped.

[303Guy]

I think both surfaces need to undergo metal transfer to qualify as galling. Lead smearing onto the steel surface is taking place and subsequent lead transfer between the smeared lead and the next boolit could be galling. Lead can also get there by deposition of liquidised lead from gas erosion.

[Reload3006]

In turning operations and milling operations Aluminum especially will adhere to the cutting tool. So will copper and brass. Its not to much of a stretch to think that lead would do the same thing. Coolant or Soluble oil is used to both keep the tool cool and to help prevent adhesion. Is the same thing happening in the bore of a gun with bullets going down them? dont know but it sounds reasonable to me. It also sounds reasonable to me that hot gasses cut and melt away the base and sides of boolits and leave that melt as solder in the bores. It has also been quasi proven at least to me that Fit is king that prevents gas from cutting the sides of the boolit will prevent leading. My theory is its a little bit of all.

[44man]

Galling is a cold microwelding process with the same metal when they are not protected by an
oxide layer. I have never heard the term appliedto dissimilar metals. SS can gall with SS and
aluminum can gall to aluminum very badly if neither piece is anodized.

Bill
True! When Ruger moved to stainless they found the problem and had to change steels for parts. Even a small change in stainless stopped it.
Galling with boolits does involve the same metals so if some is in the bore, it will pick up more from the next boolit if the lube does not prevent lead from sticking to the steel.
The only guns that smooth is not good in are ML's with patched balls and maybe guns with paper patched. Cloth and paper can polish a bore like crazy. Accuracy loss in these was attributed to "shot smooth" by the old timers.

[ku4hx]

http://en.m.wikipedia.org/wiki/Galling

There is the wiki on galling. I always take wiki with a grain, and suggest others to do the same, but this seams reasonable.

If leadins IS galling, maybe the same things that prevent galling can prevent leading?

Maybe a smooth bore really ISN'T what we want? Maybe firelapping cuts places for lubricant to reside? Maybe very minor bore pitting does the same?

It galls me!

[blackthorn]

From Webster's New World Dictionary Third College Edition---"gall-ing"---"chafing, very annoying, irritating, vexing"

I have always considered "galling" to be in line with Webster's definition. My dad used to refer to sores that occured under certain rub points of the horse's harness as "galling", so---while i am certainly no metalurgest (sp), to me the most likely cause of galling in a bore is from rough spots (made worse by accumulated lead)?

[Iron Mike Golf]

It seemes to me that the initial deposits of lead would not be galling. What about shooting when the bore already has lead fouling? I dunno. I don't think it matters whether the continued buildup is from galling or just the fouling mechanically scraping more lead off each successive round.

There's a lot of evidence that points to a rough bore contributing to lead fouling. Copper fouling, too, for that matter.

[geargnasher]

Bores lead by the three mechanisms if you want to define "galling" technically: Abrasion, particle deposition, and galling.

When lead rubs off on a rough forcing cone, rust pit, patch of copper fouling, or machine mark, it's abrasion. The lead that "sticks" then attracts more lead by galling and the lead deposits can get smeared or streaked by the mechanical action of further shooting.

When obturation fails and gas leaks occur, the boolit gets "cut" by the high pressure gas and the small lead particles stick in the microscopic pores and machine marks in the barrel, where again subsequent shots can accumulate by true galling action, as well as continued gas cutting if the problem isn't remedied.

Gear

[405]

Hah! No idea the exact word to use (galling, abrasion, colloidal deposition by plasma, etc.) but when I see it I can recognize it. Also, all other things being equal, never saw a rough bore outshoot a smooth one and never saw a rough bore foul less than a smooth one- whether cartridge or muzzleloader.

About the "shot smooth" stuff. My theory, as good as any ole wive's tale I figure, is that when old timers noticed accuracy fall off in an otherwise smooth bore they didn't examine or explore the possibility that the REAL cause was simple land wear and/or leading edge land wear- particularly in the first few inches in front of a seated bullet, whether it be cartridge or muzzleloader.

[leftiye]

Steel on steel galling can be prevented by a lubricant layer. You can even get galling when fitting by hand parts that interfere. Better lube, less galling. This part is at least similar to the leading issue.

[beagle]

Yes, you can get a barrel too smooth and it will lead easier. When my shooting partner was still around he was experimenting with impact coated moly cast bullets with no lube.

We hand lapped a Shillen barrel for about 3 days and beleive me, it wa smooth as a baby's hind end. It leaded. A similiar barrel he was using but was not as far into the lapping process didn't lead.

He scratched his head for about three days and went back in with some rougher compound and hit it again which roughened the bore slightly and with the same components, it didn't lead.

Based on these experiments, you can get a barrel too smooth for cast bullets and it will enhance leading.

On normal factory barrels, I beleive we're in good shape though./beagle

[subsonic]

The kind of roughness i'm talking about would not be seen with the naked eye. It would require a borescope at a minimum.

Interesting story Beagle!

[44man]

Hah! No idea the exact word to use (galling, abrasion, colloidal deposition by plasma, etc.) but when I see it I can recognize it. Also, all other things being equal, never saw a rough bore outshoot a smooth one and never saw a rough bore foul less than a smooth one- whether cartridge or muzzleloader.

About the "shot smooth" stuff. My theory, as good as any ole wive's tale I figure, is that when old timers noticed accuracy fall off in an otherwise smooth bore they didn't examine or explore the possibility that the REAL cause was simple land wear and/or leading edge land wear- particularly in the first few inches in front of a seated bullet, whether it be cartridge or muzzleloader.
It is true. Old timers would etch a bore with urine on their muzzle loaders. I have used vinegar to bring back groups. Scotch Brite works too.
Just try to get accuracy from a chrome plated muzzle loader.
Smooth works better for "j" word bullets.

[40Super]

Beagle:: Would it be possible that the leading in the extremely smooth bore could have been from the bullets not gripping the rifling and "skidding" somewhat down the barrel.That would be a different type af leading than the "normal".I have found some 45acp barrels that needed harder cast bullets to grip the very shallow rifling , otherwise the bullets would shoot poorly(not properly stabilized) and leave strips of lead only on one side of the grooves.
Some of the best shooting barrels I have used always had sharp ,square,and crisp rifling.Not radiused edges like what would/could happen with three days of polishing. Just a thought.

[geargnasher]

It has to do with increased surface area and no microscopic lube reservoirs in a slick barrel. One reason why lube choice can become critical at high velocity is because the lube does leave a trace behind and is affected by barrel and ambient temperature. The little boring machine marks on the bore and cut marks in the grooves hold lube and powder fouling and alter the friction characteristics of a bore. Think about flat-palming a pane of textured, stained glass and how your hand will easily slide across it, but do the same to clear plated glass and it sticks.

Also think of engine cylinder walls, it's important to have a "crosshatch" pattern of the correct depth and angle to hold engine oil on the cylinder walls or the rings will eat themselves up, gall, and sieze.

Gear

[W.R.Buchanan]

Mt44gun had the correct definition of galling. Galling occurs when similar or the same metals come into contact with no lubrication between and metal physically transfers from one surface to the other, and does so simultaniously.

Simply put, it is two pieces of metal, friction welding themselves together due to pressure that exceeds the surface tension of the material. The most common example of galling is Stainless steel nuts and bolts. If put together with no lubricant they will gall as soon as there is pressure put on the threads. It is a virtual certainty. Got 40 years of "been there done that!"

You can also gall American Cheese by rubbing two pieces together. The effect is the same as with stainless steel. I don't know if American Cheese would gall when rubbed against Swiss Cheese as there is a significant difference in the hardness of the materials.

The reason why normal steel hardware doesn't gall as easily as stainless does is because of the differences in hardness between the nuts and bolts, and also because of the properties of the material. Stainless tends to be gummy when cutting due to the high nickle content that gives it it's corrosion resistance. Whereas Cro Moly(yes most bolts are made from Cro-Moly steels) tends to have more inherant lubricity. We are not talking much more here, just enough to prevent galling. Plating of bolts tends to lessen galling as well.

However if you put a Grade 8 Bolt together with a Grade 8 Nut and apply enough pressure with no lubrication it will gall too. It's just you seldom see this as the amount of pressure required to force galling is seldom reached before the bolt twists off or the threads strip.

Leading of a barrel is not really accurately described as "galling." It is more accurately described as "soldering." As the melted lead is stuck onto the bore and not part of the bore itself.

I could see also that a severly pitted bore could receive lead by shaving it until the pits were full, similar to what happens when you smear peanut butter onto an english muffin. I would not consider this to be galling in the strict sense of the word. I would call it "filling the nooks and crannys" just like Thomas' English Muffins describes it. However subsiquent buildup of lead onto the already leaded surface could be construed as galling.

If it gets that bad you've got a pretty serious problem.

All this talk about cheese made me hungry!

Randy

[theperfessor]

One time I read that a particular turbine engine manufacturer was trying to increase the time an engine could go between overhauls by slicking up the fit between the rotor and housing bearings. They polished the surfaces to increasingly finer levels and found out that beyond a certain point performance was reduced. There was simply no irregularities to hold lubrication. Then they studied the texture of the surface and discovered certain textures such as tiny deep pits performed better than larger but shallower pits.

I would infer that something similar might govern leading and lubrication needs.

[subsonic]

You can also gall American Cheese by rubbing two pieces together.

LOL!:mrgreen::bigsmyl2:

[leftiye]

How can that be? Cheese has a lot of fat (lubricant) in it, should preclude galling. Still ain't no good for bearing metal though.:kidding:

[leftiye]

Probly cheap cheese that ain't aged long enough LOL.