Bullet "Lube" - Does it lubricate or Seal or Something Else?

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John Alexander posted this 23 August 2018

Does it really lubricate or is it like a liquid piston ring and help seal the gas behind the bullet and reduce gas cutting?

How does it affect bore condition that we would like to stay constant but often doesn't requiring frequent bore cleaning to prevent declining accuracy?

Is it needed at all and if so when?

If needed, how much is needed. Some people shoot multi groove bullets with lube in all the groves. Others limit it to the tiny groove in front of the gas check. Both win matches.

Why don't we shoot cast bullets with no lube at all in situations where we can as we do with air guns?

Can we learn something by discussing and researching this topic or is present practice good enough.

John

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pat i. posted this 23 August 2018

A good topic John and I'll hold off on comments for a while until you get some more responses.

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frnkeore posted this 23 August 2018

Lube, isn't a liquid seal, it has no strength to do so. It does allow the driving bands to seal, by keeping them from tearing, at least in PB.

I shoot soft bullets and in my opinion, it is best to fill ALL lube grooves. Since the lube isn't compressible, when captured, between the barrel and lead bullet surfaces, it helps to keep the bullet from deforming, in the driving band area.

Most cast bullets have a lot more lube capacity than needed. I don't think that the grooves need to be more than .010 - .012 deep, even at 2000 fps. Just the capacity of one groove, should be more than enough to put the thin film of lube in the barrel, for the next shot, depending on how much bare lead needs to be lubed for that next shot.

Frank

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Ed Harris posted this 23 August 2018

https://www.engineersedge.com/lubrication/boundary_lubrication.htm

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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OU812 posted this 24 August 2018

I have been experimenting with Gearnasher's version of Felix lube. This lube is very tacky and does not work good when pan lubing. I am seeing more shots without having to clean. Fouling shot is needed after barrel cools.

Today I made a batch following the original Felix lube directions. Keeping temp very close to 300 degrees during cooking in glass measuring cup...infrared gun helps monitor temp during stirring.

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RicinYakima posted this 24 August 2018

Looking at bearings and looking at bullet / barrel interface is two different things.  A 0.001" gap on the leeward side of a land will let 50,000 carbon dioxide or nitrogen dioxide molecules pass side by side. Lubes work by the long molecules of the lube reducing gas flow and absorbing heat. Gas temperature and pressure determines what lubes work best, under the many possible conditions. Ric.

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Ross Smith posted this 24 August 2018

"Lube" probably does some of both, plus maybe other things. Shooting muzzle loading slug guns, you will find it difficult to shove the second bullet down the barrel without lube, and it keeps the fouling soft.

It must do some of the same for smokeless fixed ammo. When I was swaging my 375 slugs to the desired shape I was moving a lot of lead. By lubing first, the grease grooves stayed uniform and "clean". When sized naked the grooves would collapse and smear. That supports the sealing theory at least somewhat. 

What about the folks at whites lube, do they ever post here?

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Ken Campbell Iowa posted this 24 August 2018

johna:  air guns.  no lube.  0.3 moa groups.

good to keep this in mind when trying to organize what we know, have forgotten, wish for, ...and just plain fantasize ...

when shooting 50 shot ARA rimfire against the best air guns  ...  ( air guns 20?? yards, 22rf at 50 yards ) ... the best airguns/shooters were unbeatable with our rimfires.   they could shoot 200 shots into a bughole at 20?? yards ...  and that small variation was probably wind and some bench error.     

not all airguns could do that ... probably tolerances ... our team " invested " in a top air setup ... and didn't get lucky .   hey, we tried bedding and even a barrel tuner ( g ) 

*************************

back to lubrication ... as noted, air pellets don't really have any ... some play with graphite, moly, and other dry lubes .... but that may come under "  superstition " ...

so here is my * assumptions * as to why the best airguns don't have flyers >>

air :: the hollow base takes care of blow-by .......  no initial lube seal needed.  so why aren't we using hollow base cast more often ?..  or every time ?  ( are the base dimples in 22 match ammo on purpose ?? )

not sure but i didn't see any winning solid base pellets.  

air :: real soft lead ...  seals at low/first pressure ... hmmm ... harry pope used real soft lead ...

air ::  no significant crud  in the pressure gas, so constant barrel condition ....  maybe our not perfect air barrel was changing as we shot it ... but our standard was very high  ( 200 shots in same hole at 20?? yards ) .

***************

again, the above is not to draw conclusions ... in fact it might be an attempt to  bring everybody else's confusion level about cast up to my own  cool.

if we can catch enough swirling bees we can make honey !! .

ken

 

 

 

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David Reiss posted this 24 August 2018

Thoughts:

- air guns don't have high pressure hot gasses trying to cut around the projectile 
- lube doesn't for a liquid seal, the bullet base forms a seal 
- lube coats the bore not allowing powder and lead deposits to attach themselves to the bore wall (not always as       effective, depends on many factors such as lube type, powder, pressure, etc.)
- most times use as little as possible to get the job done without creating excess smoke and crud

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
- Also deal in: Land, Banjos, Nails, Firearms, Manure, Fly Swatters, Used Cars, Whisky, Racing Forms, Rare Antiquities, Lead, Used Keyboard Keys, Good Dogs, Pith Helmets & Zulu Headdresses. .

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Ross Smith posted this 24 August 2018

I think this thread is great and also it is directly linked to Joe's thread about the bullet expanding a little too much in the throat and shaving lead. For a long time I thought it was a lube problem, but my cases are a little short and I get some lead on the outside of the case mouth after firing occaisionally.

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Paul Pollard posted this 24 August 2018

Air rifle pellets are breech seated.

 

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Ross Smith posted this 24 August 2018

Breach seating keeps coming up here and there. I have a mold that is a pope style 30 cal and another that could be maybe poosibly breach seated. I'm working on a seating tool for me 1903 and then I'll give it a try. Any suggestions?

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Larry Gibson posted this 24 August 2018

"lube doesn't form a liquid seal, the bullet base forms a seal "

Not quite sure that is the case.... we know from recovered fired cast bullets fired at velocities from 1800 to 3000+ fps that the layer of lube swages them down several thousandths smaller than groove diameter.  That is even though they started out .002 to .003 over groove diameter.  Recovered .310 diameter cast of #2 alloy and WQ with a BHN of 22 - 24 measured .305 to .307 after being fired out of a barrel with a .308 groove diameter.  Tests were conducted not only by myself but by goodsteel and Lars at White Label.

LMG

Concealment is not cover.........

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RicinYakima posted this 24 August 2018

Grease is non-compressible. In the 1900-1920 period they tried dipping the bullets of cupro-nickel bullets in grease to reduce fouling. The grease build up, reduced case neck clearance, increased pressure and cracked bolt lugs on the rifles. All of this was settled a hundred years ago.

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JeffinNZ posted this 24 August 2018

Can of worms here. 

Something to consider is lead has it own natural lubricating qualities which is why it was added to petrol.

Also, we often see that the very least amount of lube on a bullet can produce the best accuracy.  IE: One groove filled only.

The following photo is a recovered .310 Cadet bullet.  It started with a reduced diameter heel that has slugged up on firing but retains what appears to be the full load of bullet lube.  Intriguing.

Cheers from New Zealand

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Paul Pollard posted this 25 August 2018

My apologies for lack of reams of data. Around 2007, I was shooting a Shilen barrel, 14 twist, 222 Rem. Bullet was a linotype RCBS 22-055 sp. 21.2 gr 3031 for a chronographed velocity of 2700 fps. The bullets were taper-bumped in a die cut with a 3 degree included taper. For one match at Washtenaw, I did not lube the bullets, although the tech sheet listed a lube.

After shooting 100yd score, George Morrison rolled up a target in front of the barrel while I cleaned it with brush and patches. We could find no lead on the target “tube” of paper.

It shot about the usual 1.5 - 2.0 groups at 100 yds. Score was maybe 170 - 180. If you need more data, I’ll have to see if I remember how to load it.

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pat i. posted this 25 August 2018

Larry what was the test medium used to catch the bullets you measured? I've never heard of bullets being swaged down by a layer of lube. If they were sized down under groove diameter and flew along on a layer of lube leading would never be an issue as far as I can figure.

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RicinYakima posted this 25 August 2018

IMHO, leading is not an issue as long as the combustion gases do not burn past the bullet, or through the lube on the barrel. Note Jeff's bullet above. Ric

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joeb33050 posted this 25 August 2018

 

I removed all lubricant from 20 sized, gas checked and lubricated 311299’s, and loaded them in 300 Winchester Magnum cases with Remington 2 1/2 Large Pistol primers and 17 grains of Unique. The cases were neck-sized in a Lee Loader die, and belled in a Lyman “M” die so that the mouth of the case touched the chamber neck. I always “M” die the case mouth until resistance is felt on chambering the case. I think that I see accuracy deteriorate when gas comes around the case mouth and down the neck. I wipe each case off after firing, making sure that there’s no gas leaking and staining. The bullets were seated to an overall length of 3.455”, which is a little longer than will allow the cartridge to freely enter the chamber. This length mashes the front of the front band of the bullet into the leade or ball seat or throat or whatever we’re calling that tapered part of the chamber from case neck diameter to the rifled bore. The bullet is a tight fit in the taper, because that shoots best for me in my guns.

 

The rifle is a Savage Tactical rifle (I’m a little embarrassed at the “Tactical”, but that’s what it says.) It has a Weaver V9 Widefield scope set at 9X.

 

I had loaded some fixed ammunition with lubricated bullets and the same load, and I fired that when I got to the range, at 100 yards. Groups were normal. I cleaned the rifle and made sure there was no lead in the barrel. When I get clean/gray patches out of the barrel with no stripes of black or dark gray, there’s no lead.

 

Then I shot two 5 shot groups with the unlubricated bullets. The first group was slightly over 2”, the second a little over 3”. Accuracy had deteriorated, which goes along with leading.

 

I cleaned the gun, which had as bad a case of leading as I can remember, about 8” ahead of the action. It took perhaps 30 minutes and 10 Lead Away patches to get the lead out of the barrel.

 

I wasn’t too surprised at the leading, but I was surprised at the cases. Starting with the fourth case, there was lead on the outside of the case neck. Maybe a quarter of each case neck was covered with lead, on the average. The lead was thin, some wiped off, but some took a fingernail and a lot of scraping to get some off. This is what I know.

 

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joeb33050 posted this 25 August 2018

 

Response by Ken Mollohan

 

Actually, I think we have some very good evidence concerning what a 'lube' does in a cast bullet load.  Consider the following:

 

1.  Unlubricated lead bullets (even though dead soft) can be fired without leading at fairly substantial velocities in air rifles.

 

2.  Dr. Mann (and a few others) have obtained decent results with unlubricated bullets, but only under conditions with fillers or when the bullet was a very precise fit in the throat.

 

3.  Otherwise, unlubricated cast bullets can be used in a firearm without leading ONLY if velocities are kept low.

 

4.  Unlubricated cast bullets can be fired all day long (even at high velocities) without any evidence of leading with Cream of Wheat (and other fine granular materials) as fillers.

 

5.  I have noticed on many occasions that the appearance of leading and lead flashing at the muzzle (when shooting normal lubricated bullets) coincided with substantial enlargement of the land marks on recovered bullets.  These enlargements can be shown to originate with the side of the land that pushes the bullet to rotate it, because flame etching marks on the bullet grooves are noticeably longer and more severe on the NON-pushing sides.

 

            Notice the pattern here:  Every single instance where bare lead can be used successfully is under some condition that eliminates or minimizes the exposure of the projectile to flame. In example one, there is no flame (unless you are getting dieseling).

 

            In example two, the base of the bullet is exposed, but not the sides -and the velocities are generally low enough to avoid abrasive enlargement of the grooves.

 

            In example three, loads are light, and so is the pressure (and flame temperature) trying to get past the bullet.

 

            In example four, the fillers have been shown to form exceedingly effective and solid firewall structures behind the bullet.

 

            Once, many, many years ago, I tried to find out what was causing leading.  The theories of the time included lead 'rubbing off' on the steel and similar absurdities.  I tried just about everything you can imagine to make lead adhere to clean steel:  Compression in a hydraulic press to 60,000 PSI wouldn't do it.  Rubbing the lead on smooth steel wouldn't do it. Rubbing it on rough steel would remove the lead, but it was just a loose, non-adherent dust.  Spinning the bullet against the steel using a variety of drills, etc left nothing that wouldn't wipe off with the finger.  So bullet velocity wasn't the problem.  In short, I have not found any set of conditions that will produce leading that does not involve flames - or at least high temperatures. All the evidence that I'm aware of seems to support a scenario that goes something like this:

 

            Upon ignition, the gunpowder quickly converts into a ball of incandescent gas at high pressure which drives it against the base of the bullet. If the load is light, and/or if the bullet is a very good fit in the throat, the gas cannot leak past in significant volume to do any damage, so the load is reasonably successful. However, as the load is increased, velocities and pressures also increase.  If the bullet is not a press fit in the throat, some gas will escape around the bullet before it begins to move. Abrasive land enlargement becomes significant, and opens channels along the bullet for flame to escape. This flame can easily exceed the melting point of steel, and it has little trouble etching low melting lead alloy from the sides of the bullet.  These molten droplets of etching are blown forward of the bullet, and then are ironed onto the steel wall of the bore as the bullet passes.

 

            (Now step aside for a moment, and go talk to someone with some experience with welding or soldering.  They'll tell you that even the slightest trace of grease or oil on their materials will reduce or even prevent adhesion, and that for a good job, the metal MUST be clean as a whistle!)

 

            I believe that - with reasonable loads -'lubricants' prevent this by fouling the steel bore, reducing the surface tension, and preventing the molten alloy from wetting and adhering to the bore.

 

            However, as loads are increased even further, several factors begin to act against the lubricant.  For one thing, as temperature of the flame goes up, so does the temperature of the lead etch droplets - and their surface tension goes down accordingly.  Eventually, their surface tension will be lower than that of the lube, and the droplets will be able to adhere to the steel.  (The weld / solder expert above doesn't even begin to work with temperatures like these!)  Also, many waxes and wax like materials will completely evaporate at high enough temperatures, and some of them may not be able to stay around long enough to wet the steel.

 

There's a lot more evidence that I could cite, but the short version is that- I believe-'lubricants' really don't lubricate anything. They just contaminate the steel surface and prevent lead from being soldered to the bore.  Does anyone have anything they think I'm overlooking?

 

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joeb33050 posted this 25 August 2018

 

Bill McGraw said:

 

Any unlubricated CB must have a proper fit in the chamber, a substantial gas check, not just a Hornady GC. If the chamber will allow it, a much larger CB diameter or a tapered bullet with a large base band would be ideal. In many cases the chamber will not allow such a larger CB to chamber. We have many compromises in dealing with ammunition.

 

Lubricant's property is to eliminate leading and other fouling by preventing larger amounts of flake or vapor lead from sticking to and building up substantially with subsequent rounds fired; all fixed ammo gas cuts to some extent; breech-seated ammo very likely does not gas cut but lubricant is still used in that discipline. In other words, lube is needed any time there is inadequate gas sealing, and that is most or all of the time. I think that is a simple enough explanation of the process of leading and lubricant's role in its use in our CB technology.

 

In order to prevent gas cutting with unlubricated CB's, some kind of additional GC with the HGC or PB designed CB's is needed. Mustafa Curtess and I still have some of your 30 and 45 cal NGG's (no-grease-groove bullets) and we are still testing them rather successfully. In my Trapdoor the 45 NGG is somewhat too small diameter to fit properly; therefore I have used cornmeal filler as a gas check with several powders suitable for 45-70 with low PSI loads that are recommended for the weaker actions, 17K PSI typical and NMT 25K PSI. I separate the powder from the cornmeal with a thin card wad and top off the cornmeal with another card wad and have used the PVC (vinyl) wad as well under the bullet; the PVC wad does a much better job than the card wads I have used.

 

I have rolled the NGG in anhydrous lanolin for a thin coat, just enough so that it will pick up a light coat of motor mica; that must be considered a lubricant using an NGG. I don't use Unique or Red Dot type powders with the cornmeal filler to avoid excess PSI spikes. I have not had any fouling and have gotten approximately 3 MOA accuracy with the NGG with cornmeal filler and using 4895-S, 2230-S and RL-7; there are others I could have used but got reasonable accuracy with the RL-7.

 

I tried using Unique with grease cookies and avoided gas cutting, but the grease cookies were difficult to handle. Wax wads were as difficult as well. Using cornmeal filler does reduce the MV to 900-1000 MV in the trapdoor. I have not attempted any higher MV's to prevent any damage to the Trapdoor action.  I do get some unburned powder in the chamber but use a flexible plastic brush to brush out the chamber.

 

I have made my own lubricants for many years and find that beeswax, anhydrous lanolin, and Neatsfoot oil are among many of the animal, plant and insect compounds that are necessary for the "anti-flux" property that we need for the "gas check" effect and prevention of accumulated fouling in the bore. Steve Hurst uses the "anti-flux" term to best describe lube's effects. Other non-polar compounds have been added to lubes with some benefit, but I avoid them if possible. Other than CB alloys, I believe that the JB's could benefit some form of lubricant to keep the bores much cleaner and consistent with many rounds fired in matches or varmint hunting.

 

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