Hexagonal boron nitride advice

[Calvin45]

after much research and deliberating, I've decided to try hbn coating/barrel treating. I want to have as much know how and information at my disposal as possible. So if any of you are using it I would much appreciate your advice and experiences, and even to learn from the mistakes of others in hopes I avoid them - ie what not to do, what didn't work.... I'm going to be using it in my .300 win mag savage long range hunter on 225 grain hornady eld match bullets, first powder tested will be imr 8133 as Hodgdon shows it pushing a 230 Berger over 2800 FPS, it's temp stable and I live in a place that routinely gets over 30 Celsius in the summer and -30 c in the winter, and it should keep things clean with that copper eraser. Hbn- what did it do for you, how did you make it work?

 

[shphtr]

The search function is your friend. If you have not already I would recommend you search for quite a long and informative thread regarding HBN from I think last year. It detailed do's and don'ts, pro's and con's, advantages, different application techniques and suppliers, etc., etc., etc.

 

[Calvin45]

will do

 

[Wedgy]

The Berger 215 at ~3,000fps with H1000(one of the most stable powders ever) is a very well known combination. Check over at Long Range Only for the many pages long HBN thread.


http://www.longrangeonly.com/forum/...300wm-215-hybrid-hbn-coated-bore-bullets.html

 

[Calvin45]

I did read up a bunch more from different threads and YouTube vids. I now have a couple hundred projectiles treated with it. I'm on an extremely limited budget so I wanted to use what I had available if possible. The consensus seemed to be that steel bbs were the ideal tumbling media. I didn't go out and buy any, I cut open a bunch of the cheaper Winchester steel 12 gauge shells I had and probably won't ever use (I've decided waterfowl hunting isn't for me) to acquire the bbs. I washed them first as bbs in shotshells are often kinda greasy. I ensured the projectiles were clean as well, shaking them around in some water with dish soap, rinsing, oven drying, sure not to touch them directly with my hands. Don't know if that matters but can't hurt. At first it was not ideal. The powder clumped/caked real thick and upon scraping it off the bullets themselves didn't seem different...no impact plating happening. I discovered that when they say use sparingly they're not kidding. I didn't think I had put that much in the container with them but it was way too much. So I wiped those initial projectiles down to remove excess coating, and tumbled again (vibratory tumbler, pill jar). Much better, still not great results though. My final solution was to heat the projectiles to 250 Fahrenheit in an oven and then get them tumbling, applied a bit of new powder to the jar. Did this for all the others too, heat them up, tumble. The dimensions of my jar were such that it it spun slowly within the tumbler in a rotary manner as well. I did research the melting point of the plastic jar of course.

 

[FURMAN]

I just put the bullets in an aspirin like bottle, dump in the correct amount of HBN, and place in my vibrating tumbler for about an hour. Be sure to tape around the lid or it will rattle off. I apply an alcohol/ HBN solution to the rifle barrel.

 

[dok7mm]

Cleaning all the contamination off the bullets is critical. I use lacquer thinner to wash everything except the tipped bullets. On the plastic tipped ones, I clean them with corncob media in the tumbler for about an hour, because it's hard to get rid of ever trace of soap. I roll the plastic tips in a clean towel to clean any dust off.

I still use Tubb's mixture of hbn. I started with it 4 years ago and have had good, consistent results.

I heat them @ 190* and use the prescribed amt of hbn. Tumble about 2-1/2 hrs, roll in a towel to polish and sack them up in freezer bags.

 

[243winxb]

https://apps.dtic.mil/docs/citations/ADA568594

See link on page.

Abstract : Molybdenum disulfide (MS2), tungsten disulfide (WS2), hexagonal boron nitride (HBN), and Lubalox are common bullet coatings that purportedly reduce friction between the bullet and rifle barrel. Three different bullets, one a solid copper design, and two jacketed lead bullet designs, were tested in the 5.56 mm NATO rifle cartridge. After coating, these bullets were test fired through a chronograph with powder charges ranging from 0.52 grams to 0.91 grams. The energies of these bullets along with a control group of uncoated bullets were plotted against the powder charges. The work of friction for each combination was then determined as the vertical intercept obtained by least squares regression to a line. The different coating and bullet combinations produced changes in friction ranging from reductions in friction of 15% to increases in friction of 19%. Given the time and expense of coating bullets, the reduction in friction is not cost effective for most applications.

 

[dok7mm]

https://apps.dtic.mil/docs/citations/ADA568594

See link on page.

Interesting! I have noted that some of my rifles showed they needed .5 to 1.0+ grains of powder to regain bare bullet velocities, while a couple more showed little or no velocity drop vs bare bullets.

I would think bearing surface length, caliber, jacket hardness, bore actual dimensions, bore condition and consistency of coating would all have an effect on friction reduction.

 

[Calvin45]

https://apps.dtic.mil/docs/citations/ADA568594

See link on page.

Hey I've actually read that page before. The full article does show that hbn was the only one that had potentially significant effects. I'm just as much in it for the extended barrel life possibility though, which is pretty well established.

 

[Calvin45]

I should mention as well I'm going into some uncharted territory. One of the bullets I've coated is the federal trophy bonded tip. It's nickel plated to begin with. To the best of my knowledge there's no info out there about hbn on nickel for bullets. I did my research though and apparently they do use hbn for all kinds of industrial applications and it works with pretty much all metals.

 

[65WSM]

No naked bullets. I shoot HBN coated bullets. It is very often that the first shot from a cold clean barrel will be in the same location as the second, third, sixth, twelfth and so on. Just as Tubbs says. You also reduce the barrel heating through friction and barrel wear. The barrels last longer. It is not hard to do. Lately I have been experimenting with less knocking off the excess with the wool sock. I have shot some wonderful groups over 500 yards with absolutely white bullets. Yes you see a cloud of HBN at the muzzle.

 

[Calvin45]

No naked bullets. I shoot HBN coated bullets. It is very often that the first shot from a cold clean barrel will be in the same location as the second, third, sixth, twelfth and so on. Just as Tubbs says. You also reduce the barrel heating through friction and barrel wear. The barrels last longer. It is not hard to do. Lately I have been experimenting with less knocking off the excess with the wool sock. I have shot some wonderful groups over 500 yards with absolutely white bullets. Yes you see a cloud of HBN at the muzzle.

Thanks a bunch for sharing your experience, it's what I'm after here! That's fascinating, the "basically white bullets" thing...can't argue with results. I would have been afraid to try that, very content with you having gone first. I have follow up questions:

1. Any issues with excessive force needed to seat bullets coated this heavily? Neck tension problems? I would have thought a layer that thick would increase projectile diameter enough to affect that.

2. How has hbn affected your velocity? Everyone has a different opinion and report about this, I want to hear yours. Generally what seems to be reported is that the reduced friction lowers pressure and with it velocity, but that the lower friction, particularly regarding the initial pressure spike when the bullet meets the rifling, allows for a significant enough increase in charge weight compared to naked bullets to allow higher velocities at equal pressure. Is that your experience?

3. If there's so much hbn on your bullets that there's a "puff" when they leave the barrel, do you have any concerns about breathing that stuff in?

4. I'm intrigued by your username. Do you indeed have a 6.5 wsm? How close does it get to .26 nosler/6.5-300 wby performance?