David Tubb, one of the winningest winners in all of riflery endorses the use of Hexa Boron Nitride (HBN) as a bullet coating. As a science geek I love materials that enhance existing systems, even if only marginally.
You may be familiar with Molybdenum Disulfide, which is commonly available on factory bullets or applied at home with a ball mill or vibratory tumbler. You might even be familiar with Tungsten Disulfide which is a tad more exotic and preferred by some. HBN, does the same thing as the other two without the use of sulfur in the mix. Sulfur can break off, mix with water to form sulfuric acid which can rapidly pit your rifle bore.
Personally I’m intrigued by the use of HBN to reduce bore friction, which should, in theory, allow you to use more powder. But just because something is intriguing doesn’t mean it’s worth doing. Let me explain.
Coating your bullets rarely changes accuracy. Coating your bullets rarely prolongs barrel life because it is the hot gasses and sandblasting effect of unburnt powder that case the bulk of bore wear. So while HBN is intriguing, and might give me a boost in velocity (and it might not, it all depends on the rifle) it won’t do much for either barrel life or accuracy which are the two things that concern me most. Don’t get me wrong, with millions of barrels out there I’m sure there are plenty that see improvements with coated bullets, which should be just about equal to the number of barrels that see groups open up with coated bullets.
There is also the matter of accuracy on the range, as part of a contest, as a pinnacle of skill practicing the art of marksmanship not being the same skills you need to line up your targets on an enemy and slap the trigger twice. The competitive shooters I know are very peaceful people, well aware of the lethal nature of their hobby. None of them go looking for trouble. And despite their training not being geared towards the act of killing another human being, they are better prepared to do so than someone who doesn’t train at all.
The “action shooting sports” like 3 gun or practical pistol disciplines are no slouches in the accuracy department. They don’t coat their bullets. They fire bullets. LOTS of them. And they train to fire them faster and more accurately than they did the previous match.
Train for accuracy first. Speed will come. If you coat your bullets, that is fine, I can’t justify the cost of doing so because I’d rather just buy another barrel (barrels are wear items, have a couple on hand at any time). So even though I find HBN an intriguing substance, I haven’t bothered to launch a coated bullet down my bore in at least a decade.
Because on the target line, the advantage of having a coated bullet is really the knowledge that you’ve done everything possible to optimize your hand load to get the most points out of the match. In a combat situation you will forget how many times you’ve pulled the trigger, and what load you have in the chamber won’t mean anything to you. If you compete, I hope you train to reach the apex of the art whether you bother to coat bullets or not. I also hope that no one has to fire for real, but better to be ready than not.