Another bullet lube tangent...

[Ian]

Just got back from the range. For S&G's I decided to test the ester grease first, actually some new stuff I made using a softer PP. Test mule today is my 16" AR-45 of the direct-impingement persuasion, bullets were ACWW from an Accurate 45-230 somethingoruther that I had designed with two small lube grooves, and 6.2 grains of some really ancient Herco from a cardboard keg.

30 rounds of the PP/Ester grouped about four inches at 50 yards, about double what this rifle does with SL-68.1, and it had a cold-start that walked in from 9 o'clock over to the normal POI. Bore was clear of lead, only had some black fouling soot from the filthy Herco. Gas system full of black, nasty oil as always, piston and rings a pretty dry, but not as dry as with soap lube. The only thing of note was some dry, crumbly PP patches inside the cases in a few places, not stuck hard, but definitely a de-oiled residue stuck in there. I wiped it away easily with a dry Q-tip. No evidence of PP was anywhere in the bore or gas system.

Next I shot 30 rounds of the beeswax/Microwax/PP/Ester lube I made last weekend. I had a blob just big enough to lube 30 (made it in an SS teaspoon) or I would have done more. This stuff feels and acts more like a real bullet lube. This stuff grouped as well as Felix and SL-68, put the first two from a clean, dry bore into the same hole and kept the group round and centered. I'm very happy with that. Bore was clean, but as per the usual deal with beeswax and filthy powder, the carbon in the works increased. Bullet holes had ink-black, wet edges. Muzzle brake had a little wetness to it also, and the bore had a few powder mummies strewn through it. Brass insides were squeaky clean where the bullets had been parked. Not bad for a wax-based, synthetic lube that makes 220'F before it starts to slump.

So there ya go, some low-pressure .45 ACP shooting for a little "proof of concept". Looks like PP might be a viable gellant to substitute for any of our metal salt thickeners, and can be used in just about any existing lube formula to raise the melt point. PP is totally inert and non-polar, so it won't interfere with any existing soap gellant and won't interfere with the migration of polar oils or additives to the surface of the bore. So far it doesn't look like PP and oil will work by themselves, but aside from sodium soap neither does anything else.

One other thing of interest with Polypropylene as a thickener matrix is it doesn't lock up the oils in low temperatures. Lithium soap won't bleed oil very well below about 20'F according to some things I've read, and most other metal soap thickeners won't either. That's why PTFE is used as a thickener in cryo-lubes, it bleeds oil when the soap thickeners won't. Another cool thing about PP is that it acts as a lube itself, unlike most soaps except Lithium. Maybe this will help us in the quest for extreme bullet lube?

Now that we just might have a workable thickener which will melt without scorching beeswax, what should I try next? I'm thinking about boosting the old NRA formula with PP like Mike did with Ivory soap. About 10% PP should get the melt point up in the 180-200'F range. If it will do that and not detract from the good properties of NRA lube it could be a major improvement. Ideas?

 

[Brad]

What was the method used to get the PP into the mix? I am very intrigued by this. Did I mention I was very intrigued?

 

[Ian]

Good old fashioned calories. The stuff goes into the oil real nice at about 300F with some stirring, and once it's in wax will blend no problemo at 250F. Gladware containers (not the lids) are where I sourced the PP.

 

[Ian]

So I just cooked up another experiment and finger-lubed 50 bulllets, but not in time to get them loaded and shot before dark.

What I did was weigh an ounce each of Gulf paraffin wax and store-brand petroleum jelly and throw those in a Pyrex saucepan on my electric hot plate. Once that was melted and up to about 350F and starting to smoke, I added 130 grains of cut-up Gladware food storage container. It took a bit of stirring and mashing globs to get it all melted in, and ended up bumping the temp to just over 400 for a couple of minutes to finish off the clear blobs and get the sides of the saucepan "rinsed" clean. I stirred while letting it cool down to 300 or so and added an ounce of pure, yellow beeswax and stirred until melted. When the beeswax had finished melting in the mix was down to about 250F so I immediately crash-cooled it by pouring the whole mess into a bigger aluminum pot that was sitting in another pot full of ice water. It set up at around 200F and was hard by 180F.

What I ended up with is a pale-yellow, opaque layer that's flexy and pretty slick. It's a tad flaky but isn't sticky at all and isn't crumbly. Flakes and crumbs can be kneaded into a ball, but it takes a little pressure. The stuff smears easily to a feather and flows about like Felix lube if both are at room temperature. I think it needs just a teensy bit more Vaseline, or maybe I cooked off some of the oil during the heating, the lube could be a little bit softer for my tastes but it flows and stays in the lube grooves very well with some finger pressure. The ring of excess lube that forms around the sizing die from the "finger lube" method peels off intact, so this stuff is just barely adhesive enough to stay on the bullets and cohesive enough to handle, but not any more than necessary. It ought to jettison well.

The melt point of the plain old NRA formula the way I make it is about 125F. This stuff, same mixture plus just under 10% polypropylene by weight, melts at near 200F. Not too shabby. I really like how it handles and applies, and I think a person could modify this recipe to take just about any oil, wax, or middle modifier, synthetic or otherwise. The PP doesn't seem picky about what it blends with, and as we know if it will mix with paraffin wax and not separate, it's pretty dang versatile.

One other advantage of the PP I forgot to mention is that within the middle of the molecular weight range it will have a specific gravity identical to the waxes and oils we use. Why does that matter? Metal soaps in grease separate from their oils at high rates of acceleration. I don't know if that happens in bullet lube or not due to acceleration alone, but it's nice to know it won't happen with this stuff.

Now for the shooting. This stuff will either suck rocks or I'll be figuring out which Lyman 45 sizer will get boiled out.

 

[Brad]

Hmmmm, wonder how a small, and I mean small, amount of Ester 100 would fit into that lube.
I know, one way to find out, right? I need to start looking at bottles at work. We certainly throat enough of them away. Will see if any have a 5 on the bottom.

 

[Ian]

The way I understand it, the lower molecular-weight stuff is more soft and flexible and the harder, higher MW stuff is crystalline. The internet wisdom I've come across indicates several (at least three) basic types of PP, one of them being "crystalline" or some such. I'm just melting stuff around the house with a 5 in the little recycle triangle and seeing what happens. The Gladware containers have worked the best of several things I've tried, but there is probably better stuff still, but at least that stuff is a constant and commonly available. So far I can tell you two things: The brittle PP containers make grainy, crumbly lube, and the quicker you crash-cool the lube, the less grainy it is.

The PP acts just like the metal soaps we've been messing with in that it melts and blends with the oil above the "drop point", and also that it "gels" when it cools to form a fibrous grease matrix. The principle difference is that the quicker the PP is cooled from its melt point, the finer the size of the matrix strands. Axel Christiernson has a nice article on this complete with microscope photos and descriptions of cooling plates where molten PP grease is sprayed to quench it as quickly as possible and get the most desirable, fine matrix formations. Playing with this stuff in the shop today I could tell the difference in feel based on cooling rate.

 

[Brad]

I wonder if we could make a bulk PP/oil mix then heat it enough to mix it with a wax?

Based on what you are saying the bottles I see at work are too hard. We need to see what softer items are made from PP.

 

[Ian]

PP and any of several oils I've tried makes a wonderful grease. K2 and about 8% Gladware makes a sticky, super-slick grease that ought to be the freakin' berries for gun slides, particularly on polymer-framed pistols. So yeah, I think you can do about anything you want with PP. Once the PP and oil are "greasified" it's a lot easier to remelt to liquid, and takes less heat. The PP also increases the viscosity of melted oil or wax bigtime, even way past the drop point. When I was making that last batch, as the PP got fully melted in, the water-thin paraffin and petrolatum mix thickened up like warm pancake syrup. The only thing I'm not sure about is how much you can reheat the PP/oil mix before you ruin the fine grease matrix. I'm also not all that sure that it matters much, most waxes we use can easily take the melt point of the PP and the whole mixture can be crash-cooled again.

 

[fiver]

NO-5 containers are every where, cool whip containers and most margarine tubs are made from it.

you gotta watch the static build up with it though as it will build up a charge of electrons.
[something else picked up from reading about the boolit coatings]
it may not matter when melted.

most plastics are made from oil so it blending with a paraffin quite well should be no surprise.

 

[Brad]

Mentioning bullet coatings makes me wonder. I might try some of my HT coating on a few bullets but over coat with a bit of BLL. The HT coating does well but doesn't seem to work as good at preventing gas cutting, the BLL should help there.

I will still look at work and see what I can find for 5 plastic in stock bottles. I could probably fill a 55 gallon drum in 2 days in most of the emptying are PP.

Ya know, I always wondered how hard it would be to shred those bottles to make a sort of buffer like shot buffer. Would require a bit of work to devise the right machine but I can sure provide the source material.

 

[Ian]

More testing, this time with the NRA/PP lube I cooked up last night. Unfortunately it wasn't as conclusive as I'd hoped. No failure points in particular, just a question mark or two. I started out with the AR-45 again, put down two ten-shot groups at 50 yards and set it aside to cool off. Then I shot a pristine, brand-new Uberti Cattleman with the .45 ACP cylinder installed. I'd lubed the revolver and wiped the bore with Ed's Red prior to the outing. The revolver put the first three into the same hole at 15 yards before I got exited and pulled a few shots to make a 1" hole with 12 rounds. Took a break and went back to the AR-45. No first cool-barrel flyer, but I did get one odd one out of a total of 40 rounds on target that flew out of the group and had a yellow-colored lube ring instead of the light grey ones. Not sure what was up with that, but I was using mixed range brass that's all over the map for length and neck tension. I got just a light haze past a very visible relax point in the carbine, but squeaky-clean throat and zero leading in the rifling origin, which had been a slight problem even with soap lube. The revolver was clean, had virtually no lube star, and a bone-dry frame. Aside from a slightly damp carbon on the cylinder face and in the upper and lower front crevices of the frame, there was no soot or oily film on the gun. This lube didn't smoke much at all. I finished the day with the revolver, this time resting the barrel in a vee-block, which it did NOT like at all and responded by flinging bullets way low and to the right. Offhand it still shot where it was pointed when the primer went off, and still would have grouped except for the hungry shakes and not-so-great trigger.

When I got home I pulled the revolver cylinder and found some crescents of plastic curling out of the front part of the chambers where there's an abrupt headspacing step. Then I remembered two cartridges had needed a little thumb pressure to chamber fully when loading it at the range, but I didn't think much of it at the time. Apparently some of the PP is building up and peeling out. I don't know if it's a big deal or not, but kind of hints at a big issue in high-pressure rifles, particularly autoloaders like my M1A. The gas system of the AR is none the worse for wear, just filthy due to the Herco and the enormous gas port being 1/4" in front of the chamber. That totals over 100 rounds of three different PP lubes through the AR with zero malfunctions or failures to go into battery, so I guess its chamber isn't gathering any plastic.

Gotta do more testing, as always. Right now I'm thinking Brad's right, a TINY bit of straight ester 100 may be in order since there's really not much in the way of lubricating oil in this recipe. I'm still stoked about the first-shot-on-target results, lack of smoke, and the 200'F melt point, LOTS of good indications for the PP as a stabilizing agent here. If all else fails, it might still be viable in combination with sodium or lithium grease.

For some reason, I'm just not seeing any plastic buildup at all in the bores, but this is only 16K PSI or so.

 

[Brad]

Sounds promising so far.
I would try a tiny, like .5% Ester 100 oil. Easy to see if that makes a difference and go from there.
I looked at work, all the stock bottles are a 2 for recycling, HDPE. Might be worth a look, I can certainly get a bunch.
I may clean out an empty tuna can and see what I can mix up.

 

[Ian]

HDPE will probably work, but it has a much lower melting point. I've made grease before with gallon water jug plastic and 15W-40 Delo.

I was thinking about 2-3% ester oil, you know, go big or go home! I can always throttle it back.

 

[Brad]

Might not hurt to try that much, will be easy to know if it is too much.
Would ATF work almost as well? Just a hint of lubricating ability but also a touch of solvent ability? It also won't suffer near as much from excessive lubricating.

 

[Brad]

I will look at 10 g each paraffin, beeswax, and Vaseline. Add in 3 gr of PP and .15 ml of Ester oil. I might need to get a syringe from work to measure that little amount of Ester oil. That would give .5 % oil in the mix.

Heat oil, paraffin, and Vaseline. Add in PP, heat till all melted in. Remove from heat, add beeswax, stir, and crash cool.

 

[Ian]

Paraffinic ATF was my first thought, then that little birdie in the Rocky Mountains spoke from my memory and reminded me that ATF is a no-go in extreme cold. I might try it anyway, but what this stuff seems to want, if anything, is a liquid to make a dynamic film. I realize that the PP will let any oil out more readily under pressure than soap-based thickners and so this lube should take even less oil to do the job than soap-grease lube, but my testing MO has always been to go to either extreme with a substance just to gain an understanding of the effects, then try to find a "happy medium" if there is one.

 

[Brad]

I agree. Sort of look for how both minimal and potentially excess oil behave then look for the sweet spot.
Seeing how easily the stuff can give up oil makes me even more think less is gonna be better. Will be easy to see if oil is excessive, the vertical stringing is pretty obvious with lube purging.

I like the reported low reside on the revolver. That is something I like, it was a favorite result of TNT use. If this is even lower then it is really gonna be nice.

 

[Ian]

I will look at 10 g each paraffin, beeswax, and Vaseline. Add in 3 gr of PP and .15 ml of Ester oil. I might need to get a syringe from work to measure that little amount of Ester oil. That would give .5 % oil in the mix.

Heat oil, paraffin, and Vaseline. Add in PP, heat till all melted in. Remove from heat, add beeswax, stir, and crash cool.

That's what I'd do. Might take it back to 300-325 for a minute just to make sure the PP is melted before crash-cooling it. Pouring the mix out thin like pancake batter onto a chilled aluminum plate of some sort (copper would be better) is a good way to suck the heat right out of it. Just quenching the container you make it in won't do it quickly enough unless it's a really small batch. I have no idea how much volume three grams of lube is, the metric system and me have a troubled relationship.

 

[Brad]

30 g is roughly an ounce. Call it 2 heaping tablespoons full. Not a lot but enough to lube a fair number of bullets.
I need to see what I have a for a good test mule. Maybe even try the 44 mag, I know what the current lube can do. The current lube is a microwax added TNT formula of some sort. I know that from the feel. Microwax always gives a tackiness that paraffin and beeswax lack.

 

[Brad]

Just did a quick conversion. 10 g is 154 and change gr.
think of a 150 30 cal each beeswax, Vaseline, and paraffin. Probably 3 drops of Ester 100 oil and a 35 gr 22 cal of PP.

I will end up with a heavy 12 ga slug in the end.