Hex Boron Nitride (hBN) Bullet Coating
Updated 10/22/1008

The hBN Bug finally bite me.  I got some of David Tubb’s 117 gr. Boron Nitride Coated Bullets and I generally liked the appearance and feel of the bullets. Although the bullet coating was not as smooth and clear has I thought it might be. I still have not shot any of David’s boron coated bullets. I am waiting for the throat to wear a bite longer on my 6XC more before I start using them.

Finished Bullets
Clear Hex Boron Nitride Coated bullets after towel wipe

There has not been very much talk going on about the New Boron Nitride coating as I thought there would be by now. I could not find anyone actually selling the hBN powder specific for bullet coating.  There is a Canadian Company, Lower Friction that has many types or grades of dry lubricants including Hex-Boron Nitride powder.  Finally one day I spotted a paragraph in an article on bullet coating at 6mmBR.com that mentioned something about the sizes or grades of Hex-Boron Nitride being used to coat bullet.
“The two particle sizes appropriate for bullet coating are 70 nm (MK-hBN-N70-Nano) and 0.50 micron (MKhBN-050). Some shooters prefer the smaller 70 nm version, while others say the larger 0.50 micron works fine. Lowerfriction.com sells 70 nm HBN for $90.00 per pound, and the 0.50 micron HBN for $79.00 per pound”, October 2008.

3 grains of Hex Boron Nitride Powder
I am using three grains per batch of 50 to 100 bullets.
Batch sizes vary based on bullet size and how I feel.

I settled on the fine 70 nanometer powder and I had to order a pound of the stuff. So I ordered a pound from the Canadian Company and got 14 ounces US.  After actually coating some bullets I am very pleased with the appearance and smoothness of the 70 nm hBN coating.  I think my coating is a little thinner then the coating on the Tubb bullets I have. I think my coating looks better than the Tubb coating, smoother and clearer. Comparing the two coatings to peanut butter, mine are smooth and creamy and Tubb’s are chucky. I imagine that the coater for Mr. David Tubb runs much larger batches than I do and I might be seeing some mechanical surface scarring on the bullet surfaces.  The extra powder seems to ball up on itself I my coating process and is easily separated out when removing bullets and pouring the balls back into the jar. I seem to see something like little powder chucks on my bullets from Tubb. I also think the Tubb coater might be using the coarser (0.50 micron) hBN powder. However so far I am very pleased with my coated bullets smoothness and appearance.

Peanut Butter Jar Process
Peanut Butter Jars in the Tumbler Process.
Extra sieve type top used to separate bullets from corn cob.

I am using my same peanut butter jars in the Thumbler's Tumbler process that I have used to moly coat bullets.  In fact I am using the same steel balls. That is after I washed the steel balls.  I sprayed some Fantastik to the jar of steel balls and shook them. Then I added some Ivory disk soap and hot water and shook again.  Rinse and rinse until water was clear of soap bubbles while pouring the balls back and forth in a couple of bowls.  The washed and rinse steel balls still had a burned brown color on them.  I dried the balls in the oven at 170 F for a couple of hours and after cooling I put them in the corn cob jar and tumbled for 24 hours.  The balls got the bright steel color back.  So same balls but new jars for both the steel and new corn cob.  Moly dust verses hBN dust, dust is dust.  There is no such thing as good dust that will not screw up your lungs.  I have a little power vent system that filters the air on my work bench which worked okay for moly dust.  I turn the vent on and work in front of it.  After reviewing the MSD Sheets on powdered boron nitride, it appears to be about the same as moly dust and better than coal or cement dust.

Coated Bullets
Fresh out of the tumbler.

The coating process is much better than Moly, no black mess.  My coating process times are the same as I used for Moly.  Three hours of tumbling in the corn cob and three hours of tumbling in the steel balls with 3.0 grains of hBN Powder. The bullets look something like sugar coated donuts when I dump the jar of steel balls with the freshly coated bullets into my sieve to separate.  The coated bullets wipe clean to the touch with a little towel rub down and remain very slippery.

Before Final Wipe
Before final towel wipe.

I most likely have white powder all over the place but you can't see it. Another nice feature about using hBN powder is I can throw the towel I used to wipe the bullets clean into laundry area and have the towel washed.  When I tried that with a towel I used to wipe moly bullets the towel was rejected, "that towel is to dirty for my washing machine". My bottom line so far is the hBN coats just like Moly without all the black mess, just some white mess you can not see.  My coated bullets have a clear satin finish and if any of it builds up in my rifle’s bore the guys with bore scopes will never find it. I will know shortly if the hBN works as well as moly.  I have a good bench mark for my 6XC barrel using 107 grain bullets and my 22BR using 80 grain bullets.  I have shot up all my moly coated 80 grain bullets and have about two range trips left of moly coated 107 grain bullets to shoot.

10/22/2008 Shooting Update
I have shot the hBN coated bullets a couple of times now at 600 yards and everything seems to be okay or a lot like Moly. Funny thing is the hBN coated bullets are shooting higher by 7/8 MOA.  I have to check the speed and see if it has changed enough for that POI change.  Good news is I had a string of fifteen shots with less than 1.5 inches of vertical which is the best I have ever seen with my rifles.  However is that do to the hBN or bullet pointing? 

If anyone would like to try using the 70 nm Hex Boron Nitride powder, I have made a few small bags with 500 grains of the hBN powder.  Enough to between 10,000 to 16,000 bullets based of what I am doing so far.  $20.00 includes shipping, just Email me to check availability.  Gone

Larry Medler

Rifle Silhouette Shooting

Silhouette Ballistics

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Released - October 11, 2008
Revised - January 12, 2010