Ian
Notorious member
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?
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?