[twoblink]

The Myth of the "Silver Ball" Treatment?

OK, I want to hear all the old wive's tales about this treatment..

And if someone can verify or deny it ever existed.

[rock jock]

Does this have to do with werewolves?

[J Miller]

Yep, In the olden days they would use only the finest silver to cast balls with. Then they would chose only the best silk to patch it with. :uhoh:
It's the only gentlemanly way to do in a warewolfe. :rolleyes:

[dfariswheel]

Yes Virginia, there is, (or at least was) a Silver Ball treatment.

It was a proprietary Colt manufacturing process used only on Python barrels.

Colt used this mysterious process on all Python barrels. A Colt worker would use a press to force a silver ball of unknown composition down each Python barrel as a final step.

I have personally talked to two people who actually saw the process.

Colt would never reveal just what the balls were made of, but both people I talked to said it looked like a bright silver metal of some sort. One witness told me that after the ball was pressed down the barrel, the bore had a brilliant, mirror look unlike anything he had ever seen before.

I don't know if Colt still does this, but somehow, I suspect they do.

[Phil in Seattle]

It's for those of us who know that brass ones just aren't good enough. :neener:

[Jim Watson]

When Parker Hale did it in England many years ago, it was just called "ball burnishing." Not so mysterious. Considering the geometry, you will see that it can only smooth the tops of the lands. Of course they will be the worst with circumferential reamer marks to iron out; any toolmarks in the grooves will be longitudinal.

It is hard to square the process with claims of tapered bores in Pythons, however. You are not going to ram a hardened sphere through a barrel and it still be tapered.

I saw it said that Kimber barrels were made with a related process in collaboration with Kart. That their barrels were rifled by cutting but smoothed with a burnishing tool like a button rifling head. Advantages of less residual stress, maybe.

[SkunkApe]

This process is called "ballizing". A hardened ball of precise size, usually of tungsten carbide, is forced through a slightly-undersized bore. This is done to control microfinish and size. Work-hardening may be a side benefit. The process is fairly common with valve bodies. It can be less costly than I.D. grinding or honing.

Take a look at this link.

http://www.ballomatic.com/process.htm

SkunkApe
Manager of Manufacturing Engineering
******* Manufacturing Company

[SkunkApe]

Jim Watson,

Reagrding the tapered barrel issue:

I'm not sure how much Python barrels are tapered, but the size change with ballizing is very small; somewhere in the neighborhood .0005" per side. If the bore is tapered more than .001" or so, some taper would still remain after ballizing.

[Jim Watson]

Skunk,

If there is a .001"+ taper and you put a ball through with the aim of burnishing .0005", either it is not going to burnish the breech end or it is going to straighten out the taper of the muzzle end. You can't make a solid ball fit both ends of a tapered hole.

A friend of mine has a Python barrel out of the gun - he switched from 6" to 4" for IDPA. I will borrow it and see if there is enough taper to measure with reloader grade tools.

[SkunkApe]

Jim Watson,

Ignoring tolerances for an instant, visualize this:

You have a bore 6" long. Its uniformly tapered from .362" diameter down to .356" diameter.

I ballize with a .357" diameter ball.

I end up with a bore that's tapered from .362" to .357" over the first five inches, and then is a consistent .357" diameter for the last inch of length.

By using a larger ball, I could move the point at which the barrel transitions from tapered to straight closer to the breech.

You are correct that, in this example, the breech end is not burnished. However, the barrel still has taper; .001" diameter per linear inch over 5" length, in my example.

I have no idea if any gun barels are tapered or ballized; I'm only speaking of manufacturing techniques in general.

[Jim March]

My EMail to the guys at http://www.ballomatic.com/process.htm

---------------
From: jmarch@prodigy.net [mailto:jmarch@prodigy.net]
Sent: Thursday, May 22, 2003 2:27 PM
To: ssaylor@ballomatic.com
Subject: Email from ballomatic.com website

I have a question on ballizing firearms barrels:

To do the fine finish on a barrel to a given ID, can we just buy the balls, load them in shells and shoot them through the barrel?

<GRIN!>

OK, that sounds nuts, but we could catch them in water tanks or sandbags or whatever...:)

And yes, I'm serious...how much for balls sized exactly .357? And your page says something about velocity as "a .22 at 100 yards", from a rifle with mild 22LR ammo that would be about...800 feet per second? By weighing a ball and looking up reloading manuals, we can sort out the powder charge necessary to get that speed with your balls...

Jim March
---------------

Their reply:

---------------
----- Original Message -----
From: "Scott Saylor" <ssaylor@ballomatic.com>
To: <jmarch@prodigy.net>
Sent: Thursday, May 22, 2003 12:17 PM
Subject: RE: Email from ballomatic.com website

I can't comment on whether it will work. I can say that you need to make sure the force is directed straight. The ball will travel the route of least resistance, which is the center of the ball, however, the initial force maybe to the left before the ball finds the center. Again, I have no idea if it would work.

As for the ball. We supply tungsten carbide balls in .0001" increments.

If the ball isn't in stock we can grind to size in days. Currently we have .3570" and .3575" in stock. 1 each is $38.00

See our Web site at www.ballomatic.com

Scott Saylor
ssaylor@ballomatic.com
National Ball-O-Matic
850 Mandoline
Madison Hgts MI 48071
ph 248.583.1338 fx 248.583.3194
---------------

My reply to that:

---------------
Thank you for your prompt reply. I may indeed be interested soon, and there's public comments going on in this subject. See also this URL:

<URL for this thread included in the EMail>

In all cases, rifle and handgun barrels have a "funnel-like pattern" at the rear that normally channels the bullet straight down the middle. It should do the same with one of these balls.

For the exact size requirement of the ball, we'll have to "slug the barrel" of the test gun in question first - that's the gunnie term for cramming an oversize lead round down the barrel with a wooden dowel rod, to measure the actual bore with a micrometer on the lead. Variances between guns even of the same make/model are common.

In the case of revolvers, we often have a problem whereby the barrel is slightly constricted at the point where it screws into the frame. The usual cure is "fire lapping", where rounds are constructed with fine grit compound instead of lubricant and a couple of dozen are shot through, removing some metal and polishing the bore. Shooting one of your balls through once or twice may have advantages over that technique, in that the metal is "compressed" instead of "removed", hardening the bore and increasing wear resistence.

In the discussion thread referenced above, you'll see people talking about tapered bores in some handguns. These are *extremely* rare, found only in very high-end pieces.

In any case, I hope that we can experiment with these things sometime soon. If nothing else, we'll set a Guiness record for "most expensive handgun ammunition EVER" <GRIN>.

Jim March
---------------

Back to THR: guys, we have GOT to try this! The potential advantages over fire-lapping are obvious :cool:.

On the other hand, we'd best be REAL careful with pressures here. And we'd need to make sure we're not dealing with a gun that has a tighter cylinder constriction than barrel bore, that could get ugly fast.

[rock jock]

Jim,

Please be my guest. I suggest you try it on a Taurus before you let loose on a Smith. In any case, once the bandages come off you can let us know how it went. :D

[Jim Watson]

Skunk,

Your arithmetic is correct.
But if I have gone to the trouble to cut a tapered bore into a gun barrel I will not approve somebody ramming a burnishing ball down it and forming a muzzle parallel. That is good for a shotgun choke but goes against what I have seen for tapered rifled barrels.

And if anybody wants to try this on their own, suggest you do NOT get a .357" ball. That is nominal GROOVE diameter of a .38 barrel and if you could somehow push a .357" carbide ball through, you would have no rifling left. Bore diameter of a .38 is somewhere around .350" or a bit less. As I said, all you can do with this system is rub the tops of the lands smooth.

[HSMITH]

Barrel steel is quite soft and elastic, and it would displace for the ball and then return at least part way to the original ID.

[Jim March]

Heh. No, if we're only pounding it down by about .0005" or less, esp if we stick to increments of no more than .0003" (buying two balls), this shouldn't be too crazy. Esp. in a strong gun like a Blackhawk or GP100.

[Jim March]

Jim Watson: yes, I realize that. As said, we'd have to slug the barrel first and then yes, work on the tops of the rifling versus bottoms.

But that's all fire-lapping does, right?

[SkunkApe]

LOL, Jim March!

PLEASE don't tell the guys at National Ball-O-Matic you got their name from me. They occassionaly quote work for me. I've spoken with Scott several times.

It won't work, either. The pressures for ballizing far exceed handgun cartridge pressures, I think. A five-ton press working on a .357 diameter will apply about 100,000 psi CONTINUOSLY through the entire stroke. The pressure in a handgun chamber/barrel will drop rapidly as the bullet moves down the barrel.

[SkunkApe]

LMAO. I just noticed you gave Scott the link to this thread.

[SkunkApe]

Jim, you're on to something. This may just work if you "sneak up" on the desired finish size by using incrementaly larger balls.

HSmith is correct in that they're may be some springback, although I belive it will be minimal. I can advise you of this if you tell me the barrel material.

I also question if you can accurately determine the size of your bore by measuring a bullet, as you described. After the bullet is forced through, I imagine there would be raised areas on the bullet resulting from the rifling grooves. You'd have to measure BETWEEN these raised areas to find the bore size. That means you'd need micrometers with pointed tips ("point mics"). Point mics will deform the soft lead, giving a false reading. You'd be better off with a digital bore mic, which should be accurate to .0005", maybe better. Either that, or purchase a set of gage pins in .0002" increments covering the expected range. These are available.

[Jim Watson]

HS, Jim - I thought the object was to smooth the surface, not enlarge the bore, not by more than a tenth or two. Any road, you would have to allow for the elasticity of the barrel, same as they do for button rifling.

Jim - Only time I tried firelapping, there was some cutting in the grooves, after all, the whole bullet is coated with abrasive. It is not much more trouble to cast a lap and do it right, anyhow.

[Jim K]

Hi, guys,

The idea that Colt Pythons have tapered bores is new to me. Is it possible that the idea of a forcing cone was misunderstood?

If those, or any other standard commercial barrels that you know of, are bore tapered, I would appreciate having the dimensions. I know some high velocity cannon barrels are tapered, and of course there was the old Halger rifle, but I didn't know of any commercial guns with barrels made that way today.

Jim

[jungleman]

I know for a fact that when making a hydraulic cylinder they would shove a ball down the tube of the cylinder during the manufacturing process. My guess would be to standardize the bore size.

[twoblink]

From what I can remember..

Some Acura engines are done like this:

You have the cylinder bore out. Then you extrude a softer metal (molybdenium is my guess) and then you silver ball it. This makes for a VERY smooth engine with equal diameter in size, and the moly will fill in all the gaps as will the ball treatment.

Jim..

I was thinking about how to accurize my Mauser barrel and get it smooth and consistent..

You my friend, are onto something..

If not, just the thought of firing a real "ball ammo" (Sorry folks, I had to say it!) out of a 357 is cool enough to try it..

[rock jock]

It won't work, either. The pressures for ballizing far exceed handgun cartridge pressures, I think. A five-ton press working on a .357 diameter will apply about 100,000 psi CONTINUOSLY through the entire stroke.
Skunk, this pressure will be directed against the ball only, not concentrically against the bore wall, correct?

[SkunkApe]

rock jock, I'm not sure exactly what you're asking.

Keep in mind I'm no expert on ballizing, but this is how I understand it.

An oversized ball is forced rapidly through a smaller bore. A steel rod, smaller in diameter than the ball, forces the ball through. The resulting bore is larger and smoother than it was before. To accomplish this, metal is displaced. If you microscopically examine a machined surface, you'll see a series of peaks and valleys that result from the machining process. These peaks are mostly what is displaced with ballizing or burnishing. The process pushes the peaks into the valleys. The force is applied to the ball by the rod, but is transfered from the ball to the barrel to flatten out the peaks.

If you're concerned about bursting or bulginging the barrell, its a possibility if the ball is too large, or the inside of the barrel is already very smooth. I'd suspect that before the barrel burst, though, you'd move the metal form the lands into the rifling grooves, essentially making a smoothbore.

If you're asking "can a five-ton hydraulic press damage a handgun barrel by trying to ram a big ball through it?", then the answer is most definately "yes". Metal has to go somewhere, its not just getting denser.

There are limits to what can be achieved with ballizing, based on the starting size and surface finish and type of material.

Hope that helped.

[Jim March]

----- Original Message -----
From: "Scott Saylor" <ssaylor@ballomatic.com>
To: <jmarch@prodigy.net>
Sent: Friday, May 23, 2003 6:31 AM
Subject: RE: Email from ballomatic.com website
>
> OK Jimmy:
> I read the talk. Let me add a few things. I know about ballizing and
> material, but know nothing about fire arms.
> 1)The biggest problem is constant force.

See below. This isn't as big a problem as you'd think.

> 2)The ball will smooth the peaks and valleys within the chamber as long as
> the force need to smooth the peaks and valleys is less than that need to
> reshape the barrel. It is possible that you'd end up with a smoother barrel
> that is .050" longer.

Well first, slightly elongating the barrel is in and of itself not a problem. Even on a semi-auto, if the barrel is fractionally longer than the slide, it's purely a cosmetic issue. On a revolver, not even that.

But I think if you go overboard you'll get a smoothbore before you get much barrel stretch. Remember, we're dealing with rifled barrels. That means there are alternating "high areas" and "low areas" around the circumference of the bore. They're about...dang, you know, I'm not sure what the variance is between high and low. .001? I know it varies between makes. In any case, that means you can't ballize more than 10% or less of the variance between "lands" (high spots) and "grooves" (low).

> 3)Without constant force the "wave" of material that a ball creates may end
> up behind the ball creating a double taper in the barrel. Seems unlikely,
> but I've since the idea occur on stainless steel parts. Our cure is to
> increase or decrease the speed of the ball.

You'd be surprised at how constant the force from a powder charge is. There's lots of different powders, each with it's own "burn rate" and power level. The goal in brewing up ammo is to have the powder charge "run out of fuel" immediately after the bullet leaves the barrel.

Point is, it's not "boom and the bullet goes coasting down the barrel", it's continuous ignition the whole barrel length, much like how the fuel/air in a car's combustion chamber burns as it pushes the piston down. For every inch longer your handgun barrel is, you get about 50 feet per second additional velocity.

> 4)As suggested by a writer, there is elasticity in the steel. For ballizing
> it is a function of material, length, and thickness. There will be spring
> back. The ball will work harden the surface, and it is unlikely that you'd
> be able to ballize twice and expect noticeable changes. Also it is unlikely
> that you'd be able to EFFECTIVELY ballizing a .350" diameter with only a
> .01% interference. We ballize with 10 times that. However, our goals may be
> different than yours and we can typically control our pre-ballized hole.

Gun barrels are generally pretty good to start with. When we "fire lap" (the process that ballizing could replace) we're getting that "last possible ounce" of performance out. Fire-lapping will generally reduce groups at 25 yards from, say, 3" to 1.5". That means you fire six shots at the target and they're landing closer together after 25 yards of flight - by an inch or a hair more. That will give you some idea of the SMALL incremental gains we're talking about.

> You may be able to more the surface in small .01% increments and see change
> after 3-4 runs. I've never tried because we do not have to and it removes
> the economics of the process.

IF we can actually "shoot" your balls, a gunsmith could buy a selection of, say, five ball sizes for each of 3 common bore sizes (.357, .429 and .454) and be able to handle a wide array of guns. Without buying any actual machine other than the reloading tools he already has, and the gun. And sandbags :).

> Also if our process seizes there is no real
> harm done to the operator.

Heh. Ya, I hear that! The good news is, when handguns blow up, the results are seldom all that serious. Not like bolt-action rifles - push those too far, the bolt (metal cylinder about 3/4" across and 6" long" can be driven straight back through your face.

The other piece of good news is that guys looking for max accuracy in a handgun are going to be using quality guns. A Ruger Blackhawk in 44Mag can take 80,000psi chamber pressure before the cylinder gives way - the ammo is rated at 43,000psi, for a 100% safety margin. Same gun in 357Mag (smaller bore, more metal in both barrel and cylinder) could probably take an honest 100,000psi load.

> 5)What about the assembly. I assume the ball is creating more interference
> and is harder than a bullet, otherwise the barrel would become smooth over
> time. So, my question is can the ball (I'm exaggerating to make a point)
> pull the barrel off where it is attached. Maybe at the wrist.

Heh. When a handgun is pushed too far, it blows "sideways" 99% of the time. I've heard one story of a very low-end piece spitting the barrel about 10 feet downrange :).

But what most people don't realize is that the lead bullets, and even copper-jacketed lead, are themselves considerably oversize from the bore and are deformed down to the barrel bore upon firing. The deformation rate is sometimes .002" or more(!) and this is *safe*. So deforming the barrel itself by .0003" or so isn't all *that* scary.

> 6) Why not ballize the barrels before assembly - are they molded (cast) as
> one?

In a revolver, when the barrel is screwed into the frame, you get a minor but detectable "constriction" at that thread point. Ballizing could, possibly, relieve that.

> 7) As a final note. We can ballize the barrel while assembled. Fixture the
> gun/rifle appropriately and push. Even push and pull. Typical ballizing is
> likely to increase the bore by .0013" - .0017" on a .350" pre hole.
> See our Web site at www.ballomatic.com

How much would you charge to ballize a barrel to a given spec, assuming a competent machinist had already measured the bore and determined what size ball needs to be used?

Jim

[SkunkApe]

You'll put your eye out, kid.

[owen]

I think you are on dangerous ground Jim. The force on a bullet is nowhere near constant. There is a large spike at the beginning then the force gradually decreases as the bullet travels down the barrel. Lead is soft. Extremely soft. Like butter. In addition, the burn rate of propellents is pressure sensitive. The higher the pressure goes, the faster the powder burns, raising the pressure even higher. If you were to try to shoot a steel ball down a barrel, the pressure would be incredibly high.

Actually, on second thought, the ball probably wouldn't make it past the forcing cone, because the ball would not obturate (Obturate = smoosh into the rifling). IOW the ball would get shot out of the casing into the forcing cone, and then all the gas would blow by. You would have an extremely stuck steel ball in the end of your forcing cone, and the gasses shooting past the ball would probably make quite a gouge.

On a revolver, if you stretch out the barrel shank, the barrel will no longer clock up correctly.

Oh yeah, rifling depth in say 9mm, is about .005" on a side.

[Jim March]

Oh HELL.

You're right, the gas will get by in the grooves, dropping pressure. Stuck ball is the most likely result.

DAMN.

:)

Oh well.

So that leaves sending the gun in for treatment in one of their machines. I wonder if it'd be worth it?

Another interesting question: with true spherical balls of this precision, do they have any application in gunsmithing as "go/no-go guages"?

[owen]

yeah, they do. You can buy precision balls from many companies that also make gage blocks and gage pins.

I have't used them, but my understanding is that you would use them to ensure that flow channels in a manifold are the correct size over the whole path.

[tex_n_cal]

I think I will stick to fire lapping, thank you

come to think of it, though carbide balls might be entertaining in a blunderbuss.

:evil:

[twoblink]

It seems to me, buying a ball and dropping it through the barrel will tell me if my barrel is fairly consistant.. That might be a good test in and of itself..

Also, maybe a little bit of moly powder and then stick ramming a slightly smaller ball might give something close to the desired results of filling in and smoothing the lands?