does your lube have enough friction

[runfiverun]

here's a good chance to talk about something that is rarely discussed when it comes to boolit lube.

FRICTION.

now you are just about to click off this thread, thinking dude Run has been up too late again.
but think about how does a lube actually work.
yeah it lubes.
it also seals.
it releases oils from the solids.
how does it release those oils?
and when does the release actually happen? when the wax flows?
think about that for a second [the wax flows] what makes that happen and when does it stop....
the stop point is what we call the relax point and you can actually see it happen in a long barrel with many lubes.
it looks similar to leading when viewed down the barrel under poor lighting.
is that caused by friction or heat loss ooor does the wax need further modification
to remain in a flowing state.

yeah some rambling going on,, but follow the train of thought laid out and let's see what y'all got....

[RickinTN]

[.22-10-45]

Harvey Donaldson (.219 Donaldson Wasp) wrote of this. His lube formula contained Rosin..lubrication, but with drag. Also claimed this would leave bores shining.

[fryboy]

ummm i shouldnt think before i have morning coffee

friction in it's barest essence is part of why j-words build up the pressure that they do ( with that pressure comes higher velocities ) sadly when translated to cast lead even tho that lead seems to have more ( this may not be the correct word/term i'm searching for ) lubricity than the guilding metal jacket it's softness/malleability also works against it , consider the copper fouling of a bore for a minute ... a pure copper bullet often fouls a bore more than a guilding metal jacket , the zinc in the guilding metal works much like antimony and/or the tin does in our lead alloy , it's makes it harder , also consider the quenching or heat treating process some of us use - same alloy yet in many cases a quenched casting can cure a leading problem or at the very least allow us to drive that same alloy at a higher velocity/pressure level , the mechanicism could only be the increased friction in my humble opinion by the tempered alloy

eh, i'll have to contemplate this more sometime ( after i've had some morning coffee lolz )

[btroj]

This is making my head hurt. Again. And still.

So we need something in the lube that still maintains a seal and lubrication past the relax point. We also need something in the lube to prevent over lubrication so we keep a consistent level of friction- prevent the purge flyer problems due to inconsistent friction levels.

[leftiye]

Is powder burn/ pressure buildup due mainly to friction or is it because of inertia and mass of boolit? Both I'm sure. If you reduce friction, and pressure drops, add sum powder. It'll go faster too. I kinda think the issue to worry about would be when do you lose your seal?

Would purge flyers still happen if the oil were applied and removed each time you fire? Ie. light enough to scrape off and then replace by the same boolit after it has passed. Is the need for friction, or is it for lubrication? Or is it neither, but for a consistent barrel condition that avoids boolit deformation and leading.

[btroj]

Leftiye, those are exactly some of the questions we have been asking. The consensus, amongst the hats and a few others, is that a constant bore condition is key. We want a very minimal residue left in the bore and prefer that it be something that doesn't change with time or temp. Leaving too much oil in the bore can often lead to a buildup and purge flyers. Too dry and it is like a clean barrel each shot.

[btroj]

Ok Run, I put my thinking cap on while in the shower and have a few questions.

Does the relax point pertain to the lube or the bullet? Both? I think it has far more to do with the bullet relaxing and this alters the lube "pumping" mechanisms.

Is the relax point, and it's affects on lube, part of what is causing cold barrel flyers with a lube like CR?

Is the reason we can alter a lube like Felix with a bit of Vaseline for cold weather use because it alters the way the relax point affects the lube? Would the same work for CR?

I'm thinking that at the relax point the bullet is no longer receiving the pressure from behind that it needs to maintain a solid seal with the bore. At this point the lube is no longer getting the same pressure either. This leaves a smear of lube that gets deposited at this point in the barrel. This smear becomes a barrier to all future bullets until the barrel gets warm enough to make this smear remain soft enough to present less of a problem.

Can we add something other than Vaseline to our lubes to modify the viscosity to get past the relax point? Is this why a very knowledgable lube guy kept talking about cetyl esters?

Was the residue we saw with TnT in rifles a sign of the relax point? The residue only went part way up the barrel. We assumed it was because the oils were blown from the grease due to pressure. What if it was more a case of pressure allowing the grease to break down and we were leaving the soap behind. The residue stopped around the relax point because the pressure dropped off enough to prevent further de-oiling of the grease.

I think an investigation into lube ingredients that keep a better seal past the relax point is needed. What materials have the ability to remain semi-liquid under low pressures? I think cetyl esters need another look. We thought they would be important for initial lubrication on ignition, we never thought about the relax point and farther down the barrel.

Ok guys, have at it. This is a normal discussion amongst guys in hats.

[44man]

Good thought provoking post!
I do not believe in lube being a seal, the boolit is the seal.
Purge fliers? Only if half the lube leaves a boolit at the muzzle exit. Fliers are more often caused by lead too soft so a boolit does not engage the bore straight. Barely stable with the twist is another.
The amount of lube left in the bore is very tiny and no boolit will shed all the lube in the bore. Why I don't like huge, deep grooves, just more lube to get rid of out in the air and a change in boolit balance.
Friction IS needed to retard boolit release from the brass and maintain a consistent bore condition.

[btroj]

44man, if purge flyers are caused by bullets too soft then why do some lines give them at temps over 90 but not at 70 degrees? Bullets all from same batch. I think the lube becomes too soft, loses viscosity and it leaves too much oil and too behind it in the bore.

I will say that revolvers and rifles have hugely different lube demands. The revolver has that pesky cylinder gap that changes everything. A rifle allows for seating a bullet into the lands, pretty tough in a revolver. Notice I didn't say handguns, a single shot or auto loader is more like a rifle than a revolver.

[Eutectic]

Ah yes..... 'friction'

Friction is extremely important; but not all by itself.....

I'm not sure the amount of friction (within reasonable limits) is too important either..

What we want is 'uniform friction' !! A harder target yet we seek is 'uniform friction' across the board of all conditions and influences! TALL ORDER GENTLEMEN!

What we call the 'relax point' is involved and could be important. It does 'move around' in bore location for me which I relate to powder burning rate or maybe better put, the time pressure curve of the particular load being used. It has to be uniform so total bore condition friction dynamics remain so.

I tried some Chevron Delo 400 SAE 30 oil I had no use for. I remember when Chevron came out with Delo 400. It has an additive that disperses
carbon (of which a diesel has plenty!) basically keeping deposits in solution..... We make a lot of carbon shooting boolits! Should we try and purge it? Delo 400 also has ZDDP in it Lamar.... something we kicked around earlier. Well Delo 400 SAE 30 is a 'slick' lube! I found that out! And it did seem to 'gather' (for lack of a better word) carbon up different that other lubes.... But it also blew it out! More that a lube purge if was.... more like blowing your nose! You know how you have to blow your nose more than once usually? Well, that's how the flyers went!!

I almost think our 'actual' lube component needs to be a border-line lube quality vs. a superb one....

Yes, 'uniform friction' is an extremely important part of C.O.R.E. and our quest for a boolit lube for all occasions. To achieve it requires something we haven't tried yet I believe.... Maybe Brad has a point with cetyl esters...

Eutectic

[bhn22]

I believe that the lube does act as a seal, but mostly under full pressure. Bullet lubes also prevent/inhibit lube groove collapse under pressure, lube has a multitude of functions. I always thought if interesting that bullets are typically lubed near the base, rather than at the nose. The fact that this works negates to a point the position that lube only lubricates the bore, providing a sacrificial coating for the bullet to ride on. Contradictions exist however, tumble lube, or flood coating for one, which does seemingly only provides lubrication between the bullet and the bore. Another is the lowly 38 wadcutter, many of these are only lubricated in one single center groove, and when you recover fired specimens, they show little, if any consumption of the lubrication. Obviously velocity come into play at some point, along with pressure. What I'd really like to see is pressure gun lube tests done with compressed air, rather than burning gun powder, I think that by removing the heat issue from the tests, a comparison would give us much better insight into lube performance. Now that I've managed to talk in a complete circle, I think I need to hit the coffee as well.

[wlc]

Ya'll make my head hurt. I love following all these threads. I just wish I understood more, but I am getting an education. Amazing. Carry on.

[geargnasher]

I'll try to outline what I've learned about lube in the last few years.

Boolit lube is a lubricant. It serves as a both a dynamic film barrier between boolit and barrel, and as a boundary lubricant.

Boolit lube is a dynamic micro-stop-leak sealant. The analogy here is oil film on piston rings in an engine. For short durations under pressure, even 5-weight engine oil provides a substantial decrease in the very tiny gaps present between boolit and barrel. This seal is delicate, dynamic, and dependent on pressure between boolit and barrel. Lube also acts as a self-lubricating seal. I've learned from using too much polybutene that if the lubricant is too cohesive, it won't "smear" or stretch out through the bore as fast as the boolit is traveling. In that case the film breaks up and leakage or lube deposits can occur. Too much friction or cohesion and the lube tears itself apart, generates heat, etc. It needs to be slippery (consistently so) against the barrel steel under various pressures from engraving to muzzle. A lube that is too "dry" (insufficient oil) or contains wax that doesn't melt quickly enough will cause friction variance and ultimately loss of film lubrication ability. IOW, if the lube can't make a film that keeps up with the boolit travel, the film breaks down and a boundary lubrication condition exists. If the lube doesn't have components that are tolerant of a boundary lubrication condition (dry lubricating solids like graphite, hBN, mica, talc, high melt-point wax, metal soaps, organo-metallic compounds of zinc or moly), and the fluid film mechanism that delivers those boundary lubricants where they're needed isn't working, then metal begins to rub off on metal and we get things like abrasive lead deposits and antimony wash.

Boolit lube is a barrel pre-lube. Unless breech seating or muzzle loading, some degree of boolit lube is blown around the boolit before full engraving and bore obturation (seal) is achieved. This lube mist ahead of the boolit will be "run over" by the passing boolit, and whether or not it is evenly distributed and the physical state it is in (melted, solid blobs, wet coating) affects the way the boolit will respond to the pressure behind it. Blowby can be relied upon to a certain extent to deliver boundary lubricant compounds to the bore ahead of the boolit.

Boolit lube is a friction modifier. As has been said, the lube needs to provide some drag so the powder has something other than boolit inertia alone to work against. Finding ways to formulate lube so that this boolit/bore friction is consistent from one shot to the next is the principle difficulty that we boolit lube "engineers" have been working to overcome. Slip-stop conditions due to lube viscosity variances (or more correctly, film or boundary friction variances) play hoc with barrel time and pressure curves. The viscosity of the fluid film needs to be consistent independent of temperature or pressure, as evidenced by wax-based lubes and "relax point" in the barrel. My theory on the relax point is that as pressure drops off behind the boolit, the boolit base shrinks back a bit and the gaps between boolit and barrel enlarge. In extreme cases where the seal was iffy to begin with (hard, brittle alloy, marginally oversized boolits, and/or fast, peaky powder) the gap can be sufficient to cause gas-cutting. This totally incapacitates the lube and also lays down the eroded lead particles in the bore resulting in muzzle-end leading. The general observation (false) is that the barrel is too long, the lube grooves not big enough, and the boolit is "running out of lube". What's really happening is loss of obturation due to the relax point being reached for the given system of components. In less extreme instances, the lube layer spread by the boolit will thicken significantly as the boolit relaxes and the residual high pressure in the groove causes the groove to dump its payload in the bore. There is a good reason some boolit designers incorporated a "scraper groove" in front of a sharp front band; such a boolit snowplows the bore each shot.

I read an article not long ago which discussed the results of a test done on copper-jacketed bullets that had tradtional, grease-type boolit lube applied to them. The velocity was increased (IIRC) something like ten percent and the SD numbers cut in half. Very interesting stuff.....

Theories I've had and tested: 1). Non-melting lube. This only works if the lube is the consistency of 30-weight oil. I've used JUST two-cycle engine oil on boolits and never had the slightest bit of leading or lube purging, even at over 2400 fps. If it was practical to apply to the boolits, this would be THE solution. Keep that in mind, folks. If the non-melting lube is a grease consistency, problems with cohesion, lack of lube dispersion, loss of film barrier condition all occur and leading, vertical stringing, lube smearing, etc. become big problems. Grease can't handle high speed unless it's a gelled oil like automotive chassis greases which are really a metal soap matrix like a sponge impregnated with oil. Such greases squeeze out oil under pressure and the solids mostly make it out of the barrel. Sodium grease can be an exception, though, as the long-stringy fibers of the matrix can rub off and stick to the bore as the oil is squeezed and burned out of it. 2). Granular lube filler as a stop leak and temperature-pressure-consistent friction modifier. I tried everything from Metamucil to talc to powdered paper towels and the latter worked very well IF one can keep it IN THE GROOVES. If any blowby occurs, the boolit has a hard time running over the fibers without trouble. In rifles with a very snug boolit/throat fit it was no problem, but in revolvers big globs of lube would blow around the boolit and adhere to the bore. When the boolit ran over the lube/fiber blobs lead was torn off and streaked down the bore while the fibers were ironed on. Not good. Paper is one of the most consistent barrel/boolit film lubricants there is, and also makes a very durable, flexible, pressure gasket, but it's difficult to employ in a lube without making a paper jacket. 3). Solid lubricants. This has shown some promise, but most things don't work because it's too difficult to get a consistent layer delivered to the boolit/bore interface. hBN may be the answer, my results with it as an additive to a non-melting grease-type lube have been very positive. 4). Brick grease lubes. These are made with very high concentrations of metal soap, and, in one instance, bentonite clay. Generally this works very well, but sodium soap begins to leave solid residue beyond a certain pressure (20-30K psi). Accuracy problems resulted from lithium brick-grease (and also slight leading issues until 15% wax was added), and the clay brick grease was a leading nightmare. If sodium stearate had a higher heat tolerance it would probably work well with a thin oil as a brick-grease lube, but unfortunately, once the sodium stearate begins to melt at 450F, it leaves a gummy coating in the bore.

Lots of challenges, lots of things tried. Solve one problem, create another. Still working on it. The only things that will work under all circumstances are a liquid oil or a solid, unmeltable lubricant. All we need is a way to apply them to the boolit as it goes down the bore. Ok, then we add wax. Then we have to deal with hot/cold variances, phase change energy, etc. and we're back to square one. This is why we think about this in the shower and wake up thinking about it in the middle of the night: It's a huge puzzle with many pieces.

Gear

[felix]

Excellent, Ian! Well conceived and worded. ... felix

[357maximum]

Ok Run, I put my thinking cap on while in the shower and have a few questions.

Brad......Must have been a very inefficient shower with a thinking cap that big.

Gear...All i have to say to you is.........attaboy, ya done good. I hope some day you figure out the magic elixar....then I will stop using what is merely "good-nuff". The way you put most loob alchemists "random thoughts" into a sentence that most the time makes sense is quite amazing actually. GOOD JOB

[geargnasher]

Some other things I messed with that didn't work. I tried several different approaches using polyethylene and a "synthetic wax" made of long-chain (50+ carbon atom) polyalphaolepins in an effort to make a lube that had consistent friction characteristics whether solid or melted. I made a primitive Timken-style wear tester to test film strength of various lubricants, in various phase states between lead alloy and barrel steel. My inspiration was the solid polymer lubes installed in some types of sealed ball bearings, really a "plastic bearing cage" cast to surround the bearing elements and apply a constant film of lubrication as J-sticks do in open-bearing wells. The problem making it work in a rifle? HEAT. Smokeless powder gets hot when burned in confinement and the various plastic lubes and greases I made using polymers as a gellants caused plastic fouling to condense on the surface of my bores.

Lessons learned.

1) Wax-based lubes tend to be very cold-start and temperature sensitive unless modified with just the right sort of oils/greases to provide consistent friction (or slip) regardless of phase or temperature. Congealed wax residue in the bore must be of the sort that doesn't change the boolit friction much compared to when the barrel is hot and the lube is partially liquid or even vapor. Some wax blends seem to pull this off very well, particularly ester waxes like beeswax. Carnaba, also an ester, is the opposite. Paraffin wax has a surprisingly consistent friction factor in a gun bore whether liquid or solid film, but all of the paraffins have a low film strength and tend to need help from other additives and waxes to function well as a lube/sealant. Conclusion: Wax as a carrier has some drawbacks, but generally can be formulated to work acceptably under a variety of weather conditions. The problem of hot-weather storage and low melt point still exists.

2). Metal-soap brick greases are problematic in a couple of respects. First, the thickener can become an issue in high concentrations as a barrel fouling. Also the thickener, in high concentrations, may not release the oil like we'd like it to by the time enough is added to make grease that will stay on the boolit without wax or other thickeners/carriers. Second, the base oil itself can be difficult to get right. Polyolesters, diesters, and polyglycols are very slippery and exacerbate irregularities in the gun barrel rather than mitigate them, and conventional brightstock or paraffinic oils have low viscosity indices. Low VI numbers translate to different flow rates at different temperatures, so cold-barrel or altogether cold-weather performance will be different than hot-barrel or hot-weather performance of the lube. The lube may prevent leading, but may also print in different places, throw cold-barrel flyers, or make groups large in hot weather as the viscosity falls. Polyalphaolephin oils (like synthetic crankcase oil, gear oil, or two-cycle engine oil) can be an acceptable compromise of VI, "slipperyness", and film strength, but have to be chosen carefully and don't seem to work very well when carried only by a heavy, metal-soap matrix. Final thought on metal soap as a lube oil carrier: The oil may work fine under all conditions, but the metal soap carrier becomes a liability even though it solves the melting and temperature sensitivity issues associated with the waxes.

3). Non-melting grease-like substances. So, if waxes melt in the heat and leave hard residue in the cold, then how about making a grease that will stay in the grooves and not melt, ever? Done it. There are two compounds of which I'm aware that can be formulated into EP greases that won't melt or burn in a gun barrel. Runfiverun knows about one and I know about the other. The one I'm playing with is expensive, hard to get, and has problems. It's about an NLGI #3 lubricating grease, but it has a high tack and very high resistance to slide. At low speed, less than an inch per second, it works fine, but don't try to force it because it will tear apart and leave you without a lube film. I added various waxes to this and made an acceptable lube, but only because the wax melts and makes a liquid portion that will flow at boolit speeds.

4). Solid lubricants. Thermoset paint and paper jackets are the most successful of these because they are thick and flexible and isolate/seal the boolit/barrel interface. They also don't leave much behind to affect bore condition. The "jacket" principle is sound and well-proven. Cogitating on WHY jackets work so well is key to finding semi-solid lubricants that will work well: Temperature insensitive friction characteristics, positive sealing ability, and low residue.

Some other food for thought regarding our high-speed boolit "lubrication" is the speed rating of the film lube itself. ASTM has established guidelines for determining bearing speed and the viscosity of the substance suitable for lubricating it. Sliding surfaces and rolling surfaces differ a bit, but I did some calculations one time and came up with a number for a rifle boolit at 2500 fps that was about twice what the thinnest, NLGI #000 lithium/ester grease was rated to handle. That grease had a very thin oil, about like automatic transmission fluid, and just enough thickener to make it like engine oil. So, as a rifle boolit gets up to speed in the barrel, the lube needs to be very, very thin. If the lube uses a wax for a carrier, it must melt and thin-out very quickly through powder heat, friction heat, pressure heat etc. and allow at least the "ice skate" effect of film lubrication. If it doesn't melt easily enough or thin enough, too much friction will tear the lube film apart the the boolit will skate directly on the bore. At best this means big groups, at worst, leading and keyholing.

Just like high-speed babbit bearing lubrication, a boolit seems to like a pressurized, low-viscosity oil to accompany it through a barrel. How to put it where it needs to be, and keep it there, is the rub. A heavy sodium grease has been the answer for me and a few others with the TnT lubes, but only at pistol velocities and pressures. There are also some accuracy issues with it, but I think that's mainly from using the "wrong" oil. If we could keep the sodium stearate from burning and maybe switch to a blended-molecule oil we'd have it made for all purposes.

Anybody else know a good way to keep oil on a boolit without wax or anything else that leaves a residue? Hydrogenated oils like soy wax and castor wax, together with extreme-pressure ester compounds like GY-HTO may provide some answer if we can keep them from melting in hot weather. These items are homogenous and function as both lubricants and carriers regardless of phase.

Gear

[geargnasher]

Brad......Must have been a very inefficient shower with a thinking cap that big.

Gear...All i have to say to you is.........attaboy, ya done good. I hope some day you figure out the magic elixar....then I will stop using what is merely "good-nuff". The way you put most loob alchemists "random thoughts" into a sentence that most the time makes sense is quite amazing actually. GOOD JOB

It may not accomplish a successful formula, but it keeps us entertained anyway! I'm glad R5R brought up the friction thing again, it's rather key and we hadn't discussed it directly too much. Sorry I went off on a comprehensive lube tangent, it's just that I can't think about lube friction as only one part, it's so involved with every factor of the whole.

Gear

[btroj]

Agree entirely on the relax point being bullet and pressure related. Alloy makes a huge difference too. I agree that this is the cause of the "running out of lube " leading.

Looking at MML and what Eutectic mentioning regarding needing a borderline lubricating oil could it be that we have been using too good an oil? Is a full syn 2 stroke or the ester 100 AC oil too good? Are we better off with something like a generic lithium grease and the marginally oils they use?

I still think something like a cetyl ester or even some soy wax has a place. These melt at low temps/pressures and could well help get us past the relax point. I still think the relax point is a big part of the cold weather issue with some lubes, like CR. Once the barrel warms the lube remains soft enough to flow and get out of the barrel but the first few shots leave a smear of stiff wax in the bore at the point were the pressure drops.

Gear, as usual, summed it all up pretty well. Ok, he left off wrapping grooves in string or using o-rings......

[runfiverun]

the relax point is kinda funny.

where the lube smears show up is not where the powder volume ceases to be enough to keep the boolit under pressure.
with a harder lube [carnuba red] it takes the lube a bit to drop off remember carnuba red is a mix of 7 different waxes so there is a lot going on there.
my moly complex lube is a mix of 3 waxes but also has calcium stearate and lithium stearate soaps.
it also has the metal component [moly] which I added as a heat carrier for the cold [maybe the wrong thinking at the time]
it's final component which really woke the lube up was the addition of the poe [atf] oil.

now the simple lube I come up with will occasionally need the addition of some calcium soap [alox] to help it past the relax point when used in normal speed [1600-1900 fps] applications in a rifle barrel.

what I think it really boils down to is modification of the waxes used.
the oils and [metal] fillers we use are doing nothing more than propping up the wax as it transits through the changes it makes in it's journey.

we discussed thixotropic lubes many, many times and I firmly believe we are now looking for something that is controllably thixotrpic, but [ain't there always one] control of the oils release without leaving the wax behind is about as close to the grail as we can get.
it's the waxes [soaps in some cases] left behind that have to be causing the c.o.r.e. condition that is not desirable.