"Extreme" boolit lube, The Quest...

[geargnasher]

I agree it has to be stiff enough to start out that it doesn't blow off the grooves in the throat. I'm pretty much convinced that case mouths open up and vent around the boolit just an instant before the boolit moves in most situations. How else would lube get on the outside of the case neck?

Gear

[Marlin Junky]

...once it's pushed through the sizer it becomes softer than it's normal state and is almost like a #2 grease in the lube grooves, but adheres to the lube grooves better.

I don't like those attributes... besides, don't we want it to completely blow out of the lube grooves as soon as the boolit leaves the muzzle?

Gear,

Is this what you mentioned earlier (it's a Grade 7):



MJ

[runfiverun]

umm the slight softening under pressure is a good thing.
it helps release oils that are gonna do the job we need done.
it is not gummy it is slightly tacky, and the softening will definately help it fling from the boolit at the muzzle.
if it's too hard to begin with you will have problems at the throat.

[geargnasher]

That's one of them, MJ, the one that nobody can afford. The one I'm looking at now is from Opti-lube that someone (maybe you) mentioned before, but I didn't know they had a lithium complex lube too, and it's about #7. They havea a straight lithium that has less thickener and comes in about 5-6 IIRC. Both have mineral oil lubricants, and are less than $5/lb, but you have to buy 50-lbs at a shot.

Gear

[geargnasher]

MJ, most grease, and especially the metal soap greases, don't start to work until they're under pressure. Pressure makes friction and heat, which relaxes the soap matrix and "dispenses" the lube oil to the surfaces. If it doesn't do that at the right rate in a gunbarrel, you get loss of film and blowby/friction leading and flyers. Like Felix explained, it has to purge the same every shot, but it has to melt at the right rate too. The lube has to be one consistency in the case, and one at the muzzle for it to work, like R5R and 357Max explained.

Gear

[Marlin Junky]

umm the slight softening under pressure is a good thing.
it helps release oils that are gonna do the job we need done.
it is not gummy it is slightly tacky, and the softening will definately help it fling from the boolit at the muzzle.
if it's too hard to begin with you will have problems at the throat.

But the pressure needed to flow through the luber-sizer is negligible compared to what the powder charge is going to unleash on it. I certainly wouldn't be interested in a lube "looser than" e.g., Javelina, simply for it's handling characteristics.

MJ

[Marlin Junky]

... The lube has to be one consistency in the case, and one at the muzzle for it to work, like R5R and 357Max explained.

Gear

Exactly, but that doesn't mean it necessarily has to be goose poop in the cartridge case either.

MJ

[geargnasher]

This is why viscosity is key. Viscosity is defined in terms of force, motion, and time. I think oil viscosity is evaluated by how long it takes x amount to flow through and x sized hole under the force of gravity. Grease viscosity is evaluated by a penetration test similar to a brinell test, also a function of time. A lube has to flow through the sizer holes under 40-50 psi, but needs to withstand something around 10-20K psi in a rifle before the boolit is fully engraved, but only for a few milliseconds.

Imagine an automotive shock absorber. You can compress one easily by hand if you do it slowly, but it can handle many tons of force applied suddenly with only slight movement. That's due to the viscosity of the fluid and the orifice inside. So no, it doesn't have to be goose poop inside the case neck, but if it's still too viscous to conform to micro-defects in the seal halfway down the barrel, the seal will break and leading can occur. The lube has to be viscous enough to survive launch and remain at least mostly in the grooves, then once engraved it has to handle increasing viscosity and peak pressure (in the first inch or two), then the boolit really starts to gain speed and the pressure starts to level off and the lube has to be right for that, but be getting thin enough to handle the speed (at least on the surface), and finally the lube has to thin enough to handle top speed near the muzzle without shearing at a "macro" level. The lube film shears, of course, but it has to just do it on the surface of the bore/boolit films, if it shears more than that due to being too viscous, it will ball up or "gall" and shred itself, taking the next softest material (boolit) with it. This is what happened with all of my melt-proof lubes, and I got leading near the muzzle with all of them. The clay thickener was the worst.

Gear

[runfiverun]

excellent....
viscosity and make-up are both important.
gear understands why his lubes failed, i am certain that if they were less viscous to begin with they would have worked.
the pao [zombie lube] had the necessary oils to complete the job.

i have been giving this some carefull thought. and feel the lowering of my E.yellow with the stuff bruce is sending will make this a very,very flexible lube.
if you think about mml and it's viscosuty and temp window you can see that being that thin is it's limiting factor.
if you look at carnuba red and it's window you can see it's thicknes is it's downfall.
the lube we are looking for is going to be three part lube.
with a viscosity less than silly putty and more than mml it will most likely be right close to a# 2-1/2 grease.
but it's ingredients are what will carry it through.

[geargnasher]

We could all be wrong, but I'm agreeing with you for sure.

My Zombie lube, being ISO 46/100 PAG and beeswax, has no high-viscosity oil or low-viscosity wax in it to fill in the "middle" part, and I think it needs something like Vaseline or other soft microwax, or something like a little grease or tallow to balance it out. Problem is it can't be too temperature sensitive, and can't bee too sticky or it will screw up the attributes of beeswax and low visc. PAG that are working in the lube. The middle ingredient might help prevent the lube breakdown that's causing some slight leading, and help bind in some of the oil so no first-shot flyer.

I went back and studied your Engineer Yellow lube formula, and agree that if you could cut back the beeswax to less than half, add a touch more Aluminum thickener, and more middle-weight slickum it might improve, although it seems to be working pretty well as it is at the temps tested.

MML's failure point (it's strong point at low temps) is when the high-viscosity component becomes too thin, too fast in the barrel due to the VI of the microwax used. The BW-430 turns runny too soon in the barrel, and there's nothing left to "support" the lube in the grooves. I believe much of it goes out the barrel before the boolit on hot days, leaving a dripping lube star and giving purge flyers every 3-4 shots. Re-proportioning it to about equal parts grease, micro-wax, and beeswax makes it shoot much better at high temps, but at the coldest I've tested it this formula would throw a few cold-barrel flyers because the base oil of the grease wasn't fluid enough to compete with the beeswax content (at least that's my theory). BW-431 might be better, but you have to be careful with what it might do to the low end of temperature performance. It might work like a charm to use equal parts of the same, low melt-point microwax Mike uses, with equal parts beeswax and a grease with a synthetic oil content that would handle the cold better. Mike made his lube to shoot in his climate, taking it out of context requires a reformulation.

Carnauba Red's issue is high viscosity at low temps. Like Bruce mentioned a few posts ago, if you could get the lube to behave at low temps the same way it does at high temps, you might have it made. This doesn't mean making a "temperature impervious" lube like I thought in the beginning (I think I proved that is NOT the way to go), but making a lube that goes from A to Z the same way regardless of temperature, and what ever film it leaves behind must react the same way to the passage of the boolit whether the barrel is hot or cold. Having a lube that leaves very little behind is going to factor in here. I think that's one of the keys to success with copper and paper jacketed bullets, even when lubed (dry or waxy) there is so much pressure and squeegee effect from the patch/jacket that the barrel condition is the same shot-to-shot, and there is less change from a clean barrel to a fouled barrel.

Thinking of lube as three-part is what I think will get us where we want to be, if we can find the right three parts. I believe a low-viscosity, synthetic base oil like synthetic, PAO ATF or a thin PAG combined with something like Bruce's microwax (basically Vaseline) and a thick wax or thick soap matrix is going to work.

I'm still not convinced that beeswax is unsuitable for the high-viscosity component, but I'm not ruling out the possibility that something else might be better, either.

Gear

[runfiverun]

bees wax is suitable.
even in the cold.
it's getting the amount low enough to flow in the bbl in the cold.
is what i am thinking.
the lard oil should handle the cold start, the main body of lithium overlap that, and carry down the bbl.
and the b-wax flow or not at the end.
it definately will in the heat and be viscous enough to handle the higher temps.
i need the lower visc for the cold so the lube will jettison properly.
but the resistance of the b-wax for the summer.
i know i am relying on things a bit much here,but the main lubes make up has a lot of flexibility and give in it.
i post my flow temps and air pressure for a given lube from the star as this is also a way to track the lube.

[popper]

Ever hear of this stuff? http://www.bio-lubcanada.com/en/chain-saw-oil.html
Boiling point : 235 at 255°C
Flash point : > 200°C
Freezing point : -15°C
Viscosity at -40°C : > 80cP
Solubility in water : Insoluble

Also, engine piston speeds exceed 2000 fps in many cases, the lube is up to the job, the rod, pin and piston have to take 20k G's is the problem.
Need to calculate the force on the rifling @ 2500 fps for say 5 groove? Probably have to derive it from the Gs of the bullet.

[bruce381]

more stuff on the way by the way the neatsfoot oil is /was used as a flux for tin can seaming

[runfiverun]

actually most cooking greases are recycled into some soaps and for use as food to feed pigs ,chickens,etc..
i worked in a cooking oil recycling center 25 years ago...
my b.i.l. runs the place now.
i wonder what they add to it to make it green,and adhere like that.
the 80 centipoise when cold is a lot thicker than when at room temp [it should be about 20-25 cP at 70f]
if it's cleaned up for diesel fuel it has a glycerin by-product that nobody will take, so i wonder if they remove that, or if that's what they are relying on for the cling.

thanks again, bruce.

[popper]

Bulet base force is 2400 to 4500 #, for a 6 groove, ~400-700# on rifling surface ( 250 for 12-MG). That is divided (twist ratio) to axial and radial force (~400/40). That is static, the peak pressure to 'size' the CB to the bore. Dynamic force is mostly(we hope) to accelerate the CB. Rifling pressure is then GREATLY reduced. That means the lube has to withstand the 400#/40# force and temperature. This leads me to believe that the lube doesn't need to be a high pressure grease. I back this up with the yield strength of Pb, much more force and the CB would completely strip. The 'spin limit' equation is really the axial force Pb limit, not the radial force limit. I'm thinking requirements are more like the metal stamping lube for sizing, and high speed for acceleration. I expected my lube test with rifle would cause globs of Pb at the muzzle end, but that didn't happen.
Just ran a test by sizing a RD31170RF to .310. WD and set for 2 weeks,lubed with alox. NO real force required, just felt it going across the grooves. I don't have the setup to size down .004 or greater but remember trying to in the past, lots of force needed. From slugging bbl, it took a lot to get it sized and then almost nothing to slide it sown to the other end. Maybe someone with a pistol barrel and arbor press could slug the barrel with an over sized CB and give us the force and dimension results. My thinking at this point is waxes hold the oil in place for storage and release/get converted to lube during firing.

[runfiverun]

the carrier is also a lube...
it is usually the largest part of the lube.

we need to remember that the area of the lube that is doing the work is miniscule.

i am getting a kick out of some of this, as i recall what was used in the past.
Elmer used beeswax/spring bear tallow,and another component as his lube.
i don't remember the third part though, but it was a small amount.

we are making a synthetic version, and our biggest improvement is gonna be the continous viscosity.

[geargnasher]

Larry Gibson did some pressure testing of three different twist rates in .308 with identical loads, if I remember right the equipment detected no increase in chamber pressure due to the increased twist rate from 14,12, and 10, which tells me the film strength of his lube was adequate for the test. Something occurs at very high velocity with fast twists to degrade accuracy, and some of this appears to be a result of land pressure, since the accuracy is directly affected by twist rate (my interpretation). In my own shooting, I've found that harder, and especially tougher, alloys can be shot faster with more accuracy than gummy or brittle, weak alloys, which again seems to point to boolit deformation causing the HV groups to blow. I think nose slumping to one side has been eliminated as a necessary cause because merely adding a paper jacket to the same boolit, same alloy, raises the accurate velocity window by 50-75%. Land pressure, and the boolit's ability to withstand that pressure without deformation (particularly near the muzzle where the boolit is planing against the rifling angle at VERY high forces) is key to accuracy, and I'm hoping that compounding a lube with the "right stuff" for this part of its job can help improve groups. Hence my insistence on EP properties in my future lubes, I think that maintaining the "correct" film thickness near the muzzle is critical to both accuracy and obturation.

I also think that the only reason our soft lead-alloy boolits survive to the muzzle at all is a matter of containment, rather than strength. The lead is slamming into the rifling plane at almost full-speed, and being deflected basically one groove diameter in (say) 10" (radius rotates 360 degrees, inclining two radii in the distance), which is about 1.76 degrees for a .308" groove (arctangent of [.308/10]). If you were to shoot a greased steel plate at nearly two degrees, I do believe it would leave a lead smear. But in the barrel, the boolit is contained and supported to a large extent, and can therefore sustain more shear pressure. So I think some high pressure forces are at play here, and lube film strength is a critical part of resisting them.

Let me try to do some figuring here. Near the muzzle, let's take a normal, .30 caliber at 2K fps. Let's say the bearing length is .300, and groove depth is .004". Four grooves are common on sporter rifles, so that gives us a total bearing area of.0048 square inches to carry the load. Here's where I get fuzzy, though. The boolit is accelerating, so the instantaneous velocity is what we need, and the boolit is going into the rifling angle at an increasing speed, while resisting rotation due to its inertia. So we need to calculate rate of acceleration for different parts of the barrel, radial inertia of a .308" boolit of, say, 180-grain mass (assume it's a cylinder for ease of calculations), and determine how much force the .0048 square inches is really having to support. THEN we can come up with a useful film thickness requirement, and pressure rating for the lube.

Gear

[geargnasher]

the carrier is also a lube...
it is usually the largest part of the lube.

we need to remember that the area of the lube that is doing the work is miniscule.

i am getting a kick out of some of this, as i recall what was used in the past.
Elmer used beeswax/spring bear tallow,and another component as his lube.
i don't remember the third part though, but it was a small amount.

we are making a synthetic version, and our biggest improvement is gonna be the continous viscosity.

Once again I agree totally. Beeswax itself is a very important part of a lube. Bear grease will maintain a film strength at tremendous pressure, as will lard, "Can-ola" oil, soy, castor, etc.. Most of the lube oils we have, even the natural ones, are plenty good to do the job in pistols and most expected "cast boolit" velocities in rifles, but we know that. What I think we're trying to do is get those properties to be less temperature-dependent. Maintaining an effective temperature/viscosity/lubricity/rate-of-melt balance is the bugaboo.

We also know that adding one thing changes the properties of most any other component in the lube (like adding beeswax to MML, or adding Vaseline to Felix lube, or ATF to Carnauba Red, or using stearic acid instead of sodium stearate in Felix lube), so we have to be careful. This is one reason I'm leaning toward the heavy, metal-soap grease for a carrier and skipping all the other binders, modifiers, and such: Fewer conflicting ingredients.

If we keep after this, I believe we will eventually be able to actually define the operating requirements of lube, and that alone would make formulation easier. If we can get it figured out for a grease/wax/oil compound, it might be possible to do what Felix suggested and just submit a list of specifications to someone who can spit out a formula for a single, synthetic substance that will do the job. But I'll just be happy with something that works with conventional ingredients.

Gear

[C.F.Plinker]

How does this work for your example? You have a pitch of 1.19 inches in 10 inches of travel so the angle of the rifling is 6.8 degrees. Assuming a pressure of 35,000 psi times the area of the base of the boolit (.075 square inches) gives a maximum force of 2625 pounds pushing against the base of the boolit. This force times the cosine of 6.8 degrees is moving the boolit parallel to the lands and the force times the sine of 6.8 degrees is working to spin the boolit. 2625 sin6.8 is 310 pounds. Since there is only .0048 square inches to do the spinning the pressure against the rifling is 2625/.0048 or 64583 pounds per square inch. These are static pressures and would be lowered by whatever the kinetic coefficient of friction for the lube is.

[geargnasher]

I don't follow you on how you got 1.19" pitch out of one revolution in ten inches. The driving band at any point will make a 360 degree revolution in that distance, which will deflect from bore centerline on a tangent and end up traveling 2X the diameter (I think I was wrong above saying radius) of the grooves, which would be .616" rise on the "opposite" leg. So arctangent of .616/10 is about 3.5 degrees. So the simple force vector should be about 162 lbs. in the direction of the tangent. Of course this isn't really even close without figuring in the mass and static inertia of the boolit (resistance to torsional movement) and the rate of acceleration, OR, as you pointed out, the friction. The friction, if zero, will not alter the force that the rifling and boolit are exerting on each other, though, it will only allow the energy to be converted into motion without generating heat or adding to the forward resistance of the boolit.

Gear