Hexagonal Boron Nitride

Tried that last week and the first round down the barrel dropped the primer out when I ejected the case. Some 12-15 shots later of other loads I shot a second round of the same load as the first with no issues. These were loads designed to find the top end velocity with the 6.5 Sherman/140 A-Max/R26 combination(3324fps). In the future I will be firing lighter loads when first coating the bore. I also noted that it took 1 shot of a coated bullet before the velocity settled down in both my rifle which has 1500 rounds through it and my son's which only has a couple hundred.

Cliff

Can you describe the solution you swabbed into your bore? How much HBN powder into how much alcohol?

Here's one informative article on treating bores with an HBN/alcohol solution;
hBN again, and this time I'll leave it. in SwissProducts Discussion and Support Forum

Or you could ask jfseaman!!! He's a real pal... :)
 
I'm not applying a whole lot of science to the bore coating. I put a bunch of powder in a pint jar with some alcohol, shook it up to make a slurry, and dipped my patch in to run the barrel. You can see it coat because the slop is all over the chamber and the crown and you just wipe that off. It may make the barrel last longer, but I really don't know. I just want consistent cold bore shots.
 
Can you describe the solution you swabbed into your bore? How much HBN powder into how much alcohol?

Here's one informative article on treating bores with an HBN/alcohol solution;
hBN again, and this time I'll leave it. in SwissProducts Discussion and Support Forum

Or you could ask jfseaman!!! He's a real pal... :)

Good info in the link. I mixed mine a bit thicker than he suggests, I swabbed the bore with an undersized brush, wrapped with a patch saturated with the HBN/alcohol mix followed by a dry patch. I probably used 3 of the large measures in the kit with enough alcohol to get it a little thinner than pancake batter. It covered the patch well.
Hmmm... it doesn't sound very precise or scientific as as I look at in writing:rolleyes:

Cliff
 
Cliff,
I found quite a bit of additional information from a number of additional Google searches. They all describe the mixture as approximately 1/2 to 1 teaspoon HBN to 16oz alcohol. Not a paste. A paste will undoubtedly increase pressures. One guy even provided the weight of HBN per pint of alcohol. The minimum recommended alcohol content was always 91%. And the folk that sounded like they'd had the most experience at this preferred a 99% alcohol solution. I bought a quart of denatured alcohol from Trustworthy. Again, I haven't coated any bores yet. In spite of that, I'm certain I know more than jfseaman, about just about anything and everything. :D Which isn't saying a whole lot ... :)

The consistency isn't described anywhere near what you described. More like skim milk consistency and appearance than thin pancake batter. I think you likely had too much HBN. Certainly more than what others report using. After swabbing the bore, they then allow the alcohol to evaporate prior to firing a bullet down the barrel.

The 99% alcohol was preferred for two reasons, as I recall. The HBN mixes better in the higher alcohol concentration, and the 99% alcohol solution evaporates faster than the 91% rubbing alcohol. That's a summary of the infomation I collected on HBN coating of bores. They all also said clean the bore squeaky clean prior to swabbing with the HBN/alcohol solution.

The guy presenting info on the SwissProducts Forum I provided the link to, apparently has a patent on HBN coating of bullets and/or bores. I didn't try to find and read his process, as described in the patent. He seems to believe that the HBN is more or less permanently impregnated into the bore surface by firing the first bullet down the treated bore. But the majority of those reporting in various forums didn't normally speak to that "fire impregnation" of the HBN into the surface of the bore - one way or the other.

Information on the HBN coating of bullets and bores isn't very thoroughly presented at any one source I could find. I mined multiple Forums to put together what I considered a fairly complete description/process. And of course, some folk felt like they had the only "best and correct methods". On the internet, there are plenty of self-proclaimed experts. I error on the side of letting the reader know my experience and knowledge. And provide links to the sources of information I mined information from.

And then there's jfseaman...
 
The next rifle bore I will get some denatured alcohol and thin the mix down quite a bit. 16 oz. is a bit more than I might use in a lifetime, 2 oz. of slurry may be a little more in line.
Thanks
Cliff
 
Yeah, 16oz is a LOT of solution. I provided the recipe I most commonly found while researching. It may be that making 16oz of solution is preferred in order to help ensure the appropriate HBN concentration is obtained. In order to avoid too little or too much HBN in their solution. For example, if you try to mix up 1 or 2oz of solution, you may want to research this and add the HBN by weight, because being off a tad with a volumetic HBN measurement will cause a much larger change in HBN concentration than if mixing up 16oz of solution. Myself, I was planning on mixing up either 8 or 16oz. Even 8oz will likely outlast me. However, 16oz of solution is still relatively low cost, compared to the cost of everything else we spend money on in the pursuit of our shooting and hunting hobbies, and it will help ensure I end up with the recommended concentration of HBN in solution. I think I paid ~$12 for a quart of denatured alcohol.

I may Google research again and try to relocate the source of the information that had the portion of HBN expressed in weight, per volume of alcohol. But like I stated, most folks were simply recitiing a volumetric portion of HBN per 16oz alcohol.
 
Come to think of it I may use a bit more than I was thinking. I have a 30-338win mag. with a .298 bore that has been given the Tubbs final finish treatment and is in prime condition to be HBN treated! Then there is the 250AI, 300WBY.........

Cliff
 
Come to think of it I may use a bit more than I was thinking. I have a 30-338win mag. with a .298 bore that has been given the Tubbs final finish treatment and is in prime condition to be HBN treated! Then there is the 250AI, 300WBY.........

Cliff

From what I've read, I would expect the MVs and POIs to settle down within ~2 HBN coated bullets fired down a fresh HBN/alcohol treated bore.

Would appreciate your sharing any additional HBN experiences with your other rifles... It'll be a bit before I'll be gathering any data from direct experiences with my coated bullets.
 
Round 2 of mine is this week. I narrowed down the load and this week I chrono and develop the ballistics chart. Chrono will tell all I think.
 
Stumbled onto this thread.

A treasure of info.

I'm gonna get some of this stuff and give it a go in my big girl.

We're shooting CEB 377s with 144-150 gr of H-50 BMG for velocities in the range of 2975 to 3184.

CEBs are machined thus have super fine machine marks which may well lead to increased copper fouling. The few shot's I'm fired seem to copper foul considerably more than the 350 SMKs.

It certainly looks like the HBN will allow a reduction of velocity to about 3125 which seems plenty to me, and give those pricey cases a bit of a longer life.

The CEBs shoot great in the 10 twist Pac Nor.

We'll see what happens.....
 
Here is something that I know about this. Maybe of help and might not be. I used it in a ai and a custom throat gun. Before you go into using this, you in my experience have to be able to go up at least 2-5 grains in powder capacity. And this works way better with a given load charge and powder. I have heard of gains of 100+ fps but seem the norm is 20-50 fps. I know rl 33 and retumbo gave me no improvements with coated over naked. But then I went to h1000 and the first thing that happened was I went from 2955 fps to 2875 fps. And to gain back my velocities I went up a grain and that put me at 2940, and went up 3.5 more grains to find pressure. But adding two grains gave me 3003 fps. I only had 50 coated bullets. So these are all gone and I went to clean this back out and shoot my old 2955 load and even after 35 rounds and soaking the barrel I am running 2875 avg. I have no idea how long it takes to get this out, but maybe cheaper and quicker to just coat the bullets. I have a curiosity of what happens when the bullet tips are full of this stuff, if they open the same or not?
 
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