OzFclass

Hi all,
Just after a brain pick on HBN. I was doing some reading on the subject and it appears this stuff isn't just a size standard. It seems the production process provides for a fine powder of approximately 0.5 microns, but this isn't the stuff needed to provide the lubricity we are after because it agglomerates. A further process makes the particulate a bit bigger (around the 10 micron size) and in this form it is a flat platelet that considerably increases it's ability to reduce friction.

Another snippet that I found was that there seem to be 2 methods of application. One describes pretreating the barrel with HBN held in suspension in alcohol, the second is the bullet application where it's applied the same as moly.

I note that in the moly thread here, some folks experienced a problem with applying the HBN to the bullets evenly and was wondering if anyone had tried to simply wash them in an alcohol/HBN solution and let them dry (same as the barrel pre treatment)?

Tim, the hBN may be of no use to you in a stainless barrel. It won't imbed properly in the stainless with the 90% alcohol mix. It works fine on chrome moly barrels. However EEZOX another product of Canada can penetrate the pores of stainless and allow the application of the hBN on stainless. I know of no other product. Below is a picture of my EEZOX, and a bag of hBN where you can clearly see the supply details on the label for the hBN. I got the EEZOX on Ebay. There is an Australian company selling the gear too, but I have not got it at my fingertips at the moment and they describe the application to stainless barrels.

You should be aware that the hBN is primarily used to prolong throat life, rather than accuracy. Unlike moly it is not hydrophilic. It is easily removed from a barrel with alcohol. It should not be applied over an ammonia copper solvent. It helps to warm the barrel a little.

The hBN penetrates the jackets well and it does not matter if the powder is brushed off. It applies better to the jacket if they too are preheated heated. Its not as shitty to use as moly powder, but I wear a mask all the same when handling it.

Found the site Tim. http://www.totallyballistics.com.au/#!projectile/c1yws

Note: Don't let EEZOX near your chamber, the brass may not seal.

Thanks Dave, I'm not entirely sure I'll be going down the hBN route, but if it's easy enough to clean I may just give it a bash.

In reading I've come across many proclaimed benefits and many contradictions. It might be easier just to go moly lol

What are the pros and cons of moly vs hbn?

Don't believe all the claims of better ES/SD. I have one barrel which was bought alive by using HBN, but the next few I tried it in got much worse ES/SD compared to shooting bare bullets.

BATattack wrote:What are the pros and cons of moly vs hbn?

hBN
Like all things shooting there are plenty of ideas and plenty of contradictions.
Some swear it reduces (or eliminates) cold bore variations, plenty contradict this though.
Many say it eases cleaning, some suggest it's just hiding the problem.
Many say it reduces pressure/allows higher velocities, but there are those who deny this as well.

I'll go with Rod ( I find it's generally a safe option) and say it probably depends on the barrel.

hBN is cleaner to work with than Molly and there is a consensus that it's easier to remove from the barrel.

Molly
General consensus is that it does reduce pressure and does allow higher velocities, but again there are exceptions.
It's dirty, but easy to work with.
It takes a few foulers to get it back on line after cleaning.

For me, given hBN seems to be pretty easy to apply and remove, I'll probably give it a go and see what happens. If I can gain some benefit great. If not, clean the barrel and try molly.

With all that said, I just shot half the lead up and Queens with naked bullets and no cleaning. All I'm looking for is a bit more velocity, but this may not be the barrel to do it with.

If it ain't broke,,,,,

I agree with what Barry and Frank have said on the other thread about moly. In fact, Alan would know I was not a big fan of Moly, as I put it to him years ago, that the jacket is in fact a lubricant and mentioned to him that the early buttoned barrels were electroplated with copper before the button was pulled through. We later went to a Teflon material in manufacture.

I did some experiments dipping the bullets in this stuff too. Early groups were amazing but turned to sh... The Teflon was galling as was pointed out to me - but ok for the button process.

Moly attracts water and leads to problems and hBN won’t hold up in stainless too well. Both of these materials add more variables to contend with and I simply can’t be bothered with the mess and messing around for competition rifles.

hBN may be better in reducing throat wear, not from wear and tear of projectiles, but by preventing the shooter from scrubbing out the throat with brushes, abrasives etc in order to remove carbon because the carbon will be less inclined to bind to steel. When I got the hBN, I was thinking it had greater ability to handle heat and the possibility it was about 4 times more slippery than moly. But there are issues with it binding to stainless steel.

As far as accuracy improvement, I noticed no difference except the tunes were in a different place due to the pressure curve.
I know Alan, in the early days, had a new barrel that only started performing well with moly. But I would place the use of these additives in the remedial category in this situation.

I come back to a point, that a barrel should be slugged before it is fitted to find tight and loose spots which are often a result of a poorly lapped barrel due to a trainee in the shop etc. Lapping in manufacture should only be a slight touch up to take the whiskers off. It is the bullets that do the lapping. That is different from a redial lap. Apart from the carbon issue at the throat, any pressure points in the bore will collect fouling and just maybe the coated bullets reduce the staggering of velocities in such barrels due to their slipperiness. In a quality barrel, such a problem is less likely where it has a courser lap rather than being polished which is counter-intuitive to some.

With regards the claim of reduced extreme spreads due to neck tension relief, sometimes things can be too slippery and its harder to get uniform tension with different batches of cases that may vary in hardness or wall thickness at the neck. I’m a believer in firm neck tension to assist a complete powder burn for accuracy.

With the use of overbore chambering, where a lot of heat is generated, hBN would hold up better than moly disulphide if you really felt the need to go there to prevent polishing the bore. Too smooth a bore attracts fouling, like Plasticene sticks to glass and not a rough material like a blackboard. I used to give a barrel a re-minor lap at about 700 rounds with a chamber nip to freshen the throat when I was keen. The results were more certain than with the coatings. David.

I believe it is a mistake to think we can significantly reduce barrel wear - especially near the throat - with friction modifiers.

At 50,000 psi and elevated temperatures chemical reactions happen very fast and are far from normal experience.

Think of it as a Gas Plasma a bit like an Oxy Torch periodically flashing through that throat.
Chemical consequences far outweigh physical abrasion as a cause of steel removal under these circumstances.

This also makes any comparison with Cu coating during Button rifling far less relevant.

Peter Smith.

I actually agree with you Peter, and my point about the copper was to simply state it is a lubricant and why would you add a lubricant as in the case of Moly, to another lubricant such as the copra nickel of the jacket. There are more variables to contend with using moly, and simplicity is easier to deal with. Yes, I agree you can not avoid the gas erosion that you mention in the plasma state to a great extent and so the copper lubricant is not relevant in this context but I can also say having used moly the throat wear was improved either.

But the hBN is said to make it harder for carbon to bond. In that situation throat life may be extended. However, I feel that a lot of throat wear is shooter induced by abrasives and polishing in order to remove carbon. That is not a gas erosion issue.

When melting metals with an oxy torch in a small crucible, it does not take much in the way of an impurity or slag to insulate the material being melted. It does not take much salt in water to raise the boiling point, like it does not take much, only a pinch of chemical to take air bubbles out of molten aluminium before casting it. Not being a specialist in this area, I can not be certain how moly or hBN would act.

If shooters are going to use a lubricant, I have supplied the methods for its use and if people feel inclined to use one for reducing first shot elevation issues, then I would prefer hBN.

A long time ago, on the compensation threads, I posted the graphs of pressure, temperature and velocity where it can be seen it usually took a few shots for velocity to settle. I think there is something in the temperature variance that these coating may well dampen but at a marginal level. There is the consideration of a reduction of pressures with these lubricants and the associated heat loss.

The issue becomes marginal. I think the time and energy spent on doing these things have to be balanced, but those who experiment just might click onto something.

My experience with HBN in just one barrel from new;
Using HBN factory coated bullets, throat wear was in my opinion similar if not worse than any other barrels I've used, .045" wear in 850 rounds so ok not bad. After aggressive cleaning it took about 5 shots to settle down but then went extremely well. The one thing I didn't have to worry about was carbon. I probably cleaned it more often than i should have but it shot very well for 6 ranges without issue and always straight into the 6 ring if I did my part.
I have about 400 coated rounds left then onto naked bullets. When i shot TR i used my .308 for many Queens events over 3 days without cleaning & without having fouling issues so is HBN worth it, i'm not sure, maybe helps with carbon.
Geoff

I always seem to come in at a tangent so I will throw my two bob's worth in.
I have used HBN for the past 5-6 years with various results. In the preliminary stages I was trying to find a major difference between HBN and Moly. Initially there was very little that I could discern other than the mess Moly left. I ended up forwarding eight samples of different HBN. samples of various applied coatings to a Lab in the US. that returned Electron Microscope photographs of 15,000 and 25,000 magnification showing the spread and density. Wow! The return information recommended not to use any more than 1 grain of HBN. per 100 rounds in the coating process. Any more and it looked like mashed potatoes covering the projectiles which was totally wasted. It was also considered that too much would be detrimental and add fouling of the rifling. The recommended suggestion was the coated bullet should only indicate a very slight discoloration. Following this, I found a discernible improvement. Next step was the bore!
Again, too much was being deposited with a wet solution which then ended up clagging the barrel after 100 rounds. What to do? I then carried out another experiment. I decided to free flow a very, very small and I mean small amount of HBN. in the cartridge powder column. Beware, this was at my own personal risk and others should not follow. But I did find no detrimental effect in performance, but rather an improvement of consistent velocity, accuracy and lack of barrel fouling. Needless to say I use it all the time now. I will say no more before I am hung by the testicles.

Xcalibre,
I am impressed with your work. Thanks for sharing. Hard to beat good science. David.

Xcalibre,
I think you have given the powder companies a bit more to think about. I'm thinking, burn rates can be influenced by a lot of things, whether they be single or double based powders, how long the grain is or how hollow it is. On top of that graphite is used to control burn rates too and it also doubles as a lubricant; and a suitable medium is of course ether. Ok, what else can be added to the mix in minute quantities to minimise carbon bonding, not really affect burn rates, maybe a tad, but that would mainly come from reduced pressures by way of lubrication of projectiles as well. How about we drop just a tiny amount of hBN in a container and tumble the powder with it? There would be no need for a wet medium and the burn rates would be consistent as the hBN would be distributed evenly.

A long time ago I used to drop molly powder on top of some shotgun pellets and whizz a case neck around to lubricate the case neck. But I noticed changes in pressure as I had not mollied the barrel because moly was creeping into the throat. I dropped the idea due to inconsistencies thinking there were associated problems with neck tension. I think you have hit the nail on the head with a more suitable lubricant. Well done, you have clicked onto something with an inquiring mind, smarts and practical hands on application. David.

Williada,
Thank you for the comments. You are right and that's exactly what I did do by thoroughly mixing varying amounts in grains per 500g. of powder. In testing I observed a minute fail point of complete combustion energy and backed off 50% as a plus or minus baseline. The mixing process was carried out by hand tumbling and vortex funneling of both ingredients to a very very light discernible colour change in powder texture throughout. In some grades of powder you cannot see it. I now use that one amount in all grades of the common powders I use. Over a period of time I have altered a few things slightly, these being a very small further HBN reduction, a reduced barrel cleaning regime and bullet cladding process. Advantages I have found to date have been, definitely less barrel and case fouling, more consistent burn rate, lower SD, improved accuracy compared to with and without and extended barrel cleaning periods. Some of the boys here now on the range are running bare bullets with just the HBN powder loads and swear by that alone.