Range Report

[Ian]

If you run your hand through a box of powder coated bullets and let them flow through your fingers like water, there's part of the clue.

Another clue is how easily they feed through a semiautomatic. Like poop through a goose.

So I think you guys are right and we can postulate that there are two mechanisms by which powder coated bullets function better: The first being the tough, slick surface is able to direct the bullet nose (and the rest of the bullet following it) to center with less damage, and the second being it reduces friction at the drive side land interface, which reduces abrasion, gas leakage, and inconsistencies in overall resistance as the bullet zings through the bore.

I'm interrupting some other alloy tests in my 5.56 to focus more on the pc, and do more shooting with the M1A. It blows my mind that pc will make a 10.4 bhn bullet hold the rifling at such high speed.

 

[fiver]

even if it doesn't stop the gas from flowing past, as long as the coat isn't cut there is no lead to break down and vaporize in the barrel.

 

[Ian]

I been milling over the nano-diamond thing end Tx he part where I get stuck is the film lube thing. Thats a good thing but depends on not losing the dynamic film and going into a boundary-lubrication condition. At the boundary you have to depend on moly, powder fouling, soap, sulpher, zinc, zddp, or somilar for lube. In a bad barrel it's near impossible to keep the grooves pressurized and the dynamic film thing going. Maybe the diamond stuff would help hold that film?

One thing that really wakes you up to what's really going on with hv loads is shooting through a suppressor. That antimony wash and dry bore condition that we get and still have good groups? Yeah.....things aren't as rosy as we think, the bullet is getting shredded and the lube blown out, its just that sometimes we can get the whole system to hang together well enough to do what we want even though its blowing clouds of bullet dust out the muzzle. When you use a can, you can actually tell and sometimes it's amazing just how much of the bullet never makes it to the target.

 

[fiver]

kicking this one back up so I can go through it again.

 

[waco]

So I just finished loading up 50 rounds of the XCB in New Starline brass. Same load as before. 47.5gr of H414 for just over 2600fps.
The only thing I've shot these at was my 10" steel plate at 500 yards. I want to test these at 100 and 200 yards to see what they will do.
They obviously held under 2moa at 500. I want to see If they are only 2moa accurate at 100 and 200. If they are only that good, this kind of disproves the theory that the groups will keep opening up the further they are shot.

 

[fiver]

there is no way to prove slight aiming errors aren't what is accounting for the 2 moa at 500.
you might have a 1/2" capable load at 100 then have the cross hairs pretty much cover a 10" target at 500.
or a very slight 'miss' on the barrel node that doesn't really show up till further down the road.
we can 'theory' our face off, and we can explain it away through other means.
the fact remains you have a 2 moa 500 yd. load with you shooting your rifle at that point in time because that's what your last groups were. [shrug]

 

[fiver]

I must have missed Ian's last post, because I have mulled the diamond thing over too.
it kind of occurred to me that the black nitride coating I have on some of my dies also needs a burnishing like the 'inventor' of the special round diamond say's the micro diamond stuff does too.
that and Bills [or JW's?] thread about the Ti coating on the cutting tools got me to thinking about the friction reducing capability of a film or coating.
Moly was supposed to work this way when it come out, and it did, except for the etching problem under the coating it was as advertised.
so we know a coating on a coating works without a traditional lube.
the key it seems to me is to get the coating in the barrel and then on the wear part that's moving, and burnish them together with a slight fluid film for best results.

 

[Ian]

Fire-polish the bore with lapping bullets, then shoot a bunch of powder-coated cast through it....with a traditional lube maybe to control carbon fouling? Or not. It seems to reach an equilibrium state quickly with just pc. No cold-bore flyers whatsoever after the barrel is broken in. Its looking like pc will cure most of the CORE problems we've been fighting since forever.

 

[fiver]

powder coat is a whole new something else.
if it could be combined with Hbn or something along those lines I think you'd have a damn near powder fouling free surface too.
it would just get blown out every shot.

 

[Ian]

Pc can be mixed with hBN and baked onto the bullet. The lube grooves can then be filled with an hBN lube. Dang, that just gave me an idea, I have a little container of bullet lube that Pete sent me years ago, he called it "strawberry ice", iirc it's beeswax, hBN, and ester two-stroke oil. See where I'm going with that?

 

[fiver]

if you can get it to lay down a smooth layer and then maintain it lube free later I think you'll do pretty well.
the only negative I can see is too smooth of a barrel and no friction peroperty's
you'll end up burning 50 grs of powder to get 2-K fps...LOL

 

[popper]

IMHO, a coating of BLL over PC actually coats the bore so the PC isn't abraded. My barrel is shinier with the BLL than without. Test was done in BO 170gr. PB pushed hard. While back recovered some PC 40sw, coating was no longer slick & shiny. Next test I'll wipe some veggy oil just on the nose.
Ian, ever find a solvent to cut AC oil? It's building up on my Sprue bolt.

 

[Ian]

Acetone.

I still use Amsoil Saber for sprue lube because it lasts longer per application than any other oil I've tried, including the stuff MP includes imwith his moulds.

Fiver, yeah it can get ridiculous....but that's where the lube itself comes in. Having hBN fixed in the coating and contained in the lube should give good uniformity and keep everything blown out (beeswax and ester oil burn very clean), but the lube itself is very stiff and actually adds friction. Counterintuitive, I know, but you get it, lube can add back the friction the pc loses, and hBN isn't necessarily a free-slide off into deep space if incorporated into a viscous slurry.

 

[fiver]

acetone will wash it away and not leave any residue behind.
it's also a good solvent for ATF.

I'm now thinking that big batch of Homo-lube would really benefit from some Hbn.
I finally just added all 3 batches together and bumped the wax content a little to make a pretty nice lube.
it's still just a little but slippery [i think from the extra soy wax]
I was thinking of cutting it with some of the hard batch of moly complex, but just a metal friction modifier and some clean bees-wax might be a better idea.

 

[Ian]

If you don't have any paraffin in there, you might add 5% or so of that (like taper candle paraffin, not the Gulf crap) before more B-wax. Might also add some microwax to balance the paraffin and counteract the slippery. A little paraffin sure brought SL-68.1 up a notch, eliminated the slight cold bore flyers present with some rifles and improved cool-weather groups all around.

 

[fiver]

there's paraffin, and micro-wax, and carnuba, and soy and bees wax, and soap, and mineral oil and lithium and aluminum and sulpher esters and oxidants and, and, and.. LOL.
the last pull together was with micro-wax but it's still heavy on the soy side and heavy oils.
I'm thinking bees wax as a bigger sponge to help hold some of the other stuff in a better suspension.
hmm I just remembered I still have some of that cab-o-sil stuff too it might make a less waxy sponge and add some friction property's that ain't so grabby like the B-wax is.

 

[Ian]

Fumed silica still scares me. Glass bead blasting and so forth. Beeswax is to bullet lube what butter/suger/eggs is to baking, add enough of it and it's hard to make something that doesn't work.

 

[JWFilips]

"hBN"........Oh My What is it? love to follow this thread!

Now Cab-o-sil I understand I use it in my gun finishes and "18th century grunge" for restoration

 

[Ian]

Hexagonal Boron Nitride. That super-fine, super-slick powder used as a dry lube but far better than mica or graphite.

 

[JWFilips]

And this can be mixed in with PC? Do you realize the possibilities!