Anybody hear of a neg side to HBN coating? Where is Phorwath on this? He has tried everything.
Steve
Ha ha. I was just waiting for you to ask, Steve.
I coated ~900 bullets with HBN over the past 5 days. Haven't shot a single one of them yet. I researched for many hours before deciding to proceed with it. HBN provides all the positives of Moly coating (which I've never done), without any of the negatives of Moly.
Moly burns/melts at ~ 600F, whereas HBN doesn't burn/melt till around 1,700F. Which means HBN doesn't melt or build up in the bore. HBN is a white powder and doesn't turn everything that touches it brown/black like Moly.
I'll also be coating my bores with a HBN/99%alcohol slurry prior to firing the HBN coated bullets.
Again, I've not fired a single HBN coated bullet yet. However my
'ARMCHAIR' knowledge of reported benefits includes:
1) Obtain higher muzzle velocity. I'm expecting to gain ~35fps MV with equal operating pressures. But more is possible, depending on bore/bullet bearing length, cartridge, MV, etc.;
2) Increases bore life. Less bullet to bore friction, and some claim the HBN coating inside the bore and in the throat area helps reduce throat erosion;
3) Easier on bullet jackets. Less friction = less heating up of the bullet jacket. Some have reported that they've been able to shoot HBN coated bullets when those same non-coated bullets weren't surviving the lauch down their bores. This could be of benefit to those shooting long heavy lead core jacketed bullets in fast twist rate barrels, at high speeds;
4) Less bore fouling per shot fired. More shooting - less cleaning. Competition shooters are finding they don't have to clean their bores nearly as often;
5) HBN doesn't pose a corrosion problem inside the bores. Moly in the bore is evidently troublesome;
6) Clean bore / cold bore shots yield same point of impact as the fouled bore shots. David Tubbs uses and promotes HBN due to this benefit in competition. He's been using the stuff for 10 yrs now and recommends it specifically because of the cold bore shot consistency.
7) Lower ES and SD, likely due to a number of causes. Less bore friction alone would yield lower MV spreads. There's also more consistent release from the neck with the lower coefficient of friction between bullet & case neck;
8) If you're pressuring out before reaching the next higher MV node, HBN coating may allow you to take advantage of an additional 35-80fps MV.
Here's some copy and paste information I provided to another Forum Member recently:
"
A single "container" is the round plastic pill bottle seen in the Cabela's vibratory tumbler. This container is about 1/4 filled with stainless balls, and 1/2 filled with bullets, and 1/4 air space. Add about 1/3 teaspoon of HBN powder (more on the initial use of the stainless balls since they will collect HBN also. It's important that your container be round so that it will continually roll over (rotate) in the vibratory tumbler (like a clothes dryer drum), ensuring the HBN powder is thoroughly mixing with the bullets and stainless balls during the 1 hour vibratory tumbler session. David Tubbs advised only one pill bottle at a time in the vibratory tumbler to allow best impact plating. Tubbs uses a vibratory tumbler. Not a rotating tumbler. I've read folk arguing both ways. Too much weight in the vibratory tumbler means less vigorous vibratory energy available for impact coating the jackets.
I degreased all of my bullets and the stainless balls with acetone prior to treatment. I pre-heat the bullets & stainless balls in the pill bottle in the oven @ 175F. Pre-heat oven to 175F, turn oven off so electrical element can't glow red hot, place pill bottle on a small dish and let everything soak up the heat up ~20 minutes. I've read heat assists in the impact plating of the HBN on the bullet jacket. Any oil or grease on the bullet jackets will prevent impact plating. I vibrate a single container for 1 hour in this Cabela's vibratory tumbler (made by Berry's). I've HBN coated about 500 bullets so far this weekend. All is going well. The appearance and feel on the coated bullets is similar to a teflon coating.
The light bulb next to the vibratory tumbler bowl on the garage floor is to provide some heat during the 1 hour vibratory sessions, as my garage is only about 55F this time of year.
Wear latex gloves when handling the HBN. I go outside when I'm messing with the HBN powder in order to minimize inhalation of the dust. It's not toxic, but still no sense in inhaling 0.5 micron particles of anything into the lungs. I wash my latex gloves off in water to rid them of HBN powder that gets on them when transferring the HBN powder into the pill container.
I bought 1-gallon of acetone (overkill). 1 quart of de-natured alcohol to make up a mixture of HBN to swab down my bores/barrels. 5 lbs of stainless 1/8" balls. A $60 vibratory tumbler from Cabela's. 8oz HBN powder from bulletcoatings.com. Some bore swabs from bulletcoatings.com, and I'm simply using a large pill bottle with a screw on sealing cap that I had around the house as my container for bullets/SS balls/HBN."
In response to how many bullets can I treat at one time in my vibratory tumbler?
"
Approximately:
100-125 215gr .308 Hybrids or 210gr VLDs.
75-90 300gr .338 OTMs
I'm guessing 150 168gr 7mm VLDs. Haven't done them yet. They're next.
Then I'll probably treat some Hornady Amax bullets, and some other bear/camp bullets that I also load and carry.
My pill container is fairly good sized. Check the photo. I included a ruler next to the container so you'd be able to see the dimensions of my plastic container.
I HBN coated about 750 bullets over the weekend. The treatment looks to have been successful.
You may or may not need to degrease your bullets with acetone. I had already handled many of my bullets with my hands - meplat uniformed and hollow-pointed them. I didn't want to take a chance on poor impact coating, so I de-greased all of my bullets prior to HBN coating.
And I'm sure there are many folks not heating the bullets prior to placement in the vibratory tumbler. I decided to preheat mine based on what I'd read while researching the subject.
The alcohol content for treating the bore with the HBN slurry is recommended to be at least 91%. 99% is preferable to 91%. So I purchased a quart of denatured alcohol. Walmart sells 91% rubbing alcohol cheap, but I went for the 99% alcohol solution for mopping the bore with HBN."
I'll post a few pictures of my equipment. The incandescent light bulb was set next to the tumbler to maintain a little heat in a 55F garage.
The ruler will give you an idea of the size of my pill container.
As I mentioned, I used an oven to pre-heat my bullets and the SS pellets prior to the 1-hour session in the vibratory tumbler. David Tubbs recommends 30-60 minutes in the tumbler. I errored on the high side and tumbled for 60 minutes.
