I started using it a few years ago for my match bullets and even coated some of my .30 cal. Ball bullets. I find it less tedious than wet tumbling brass or trimming once fired Lake City brass (AArrrgh!). I had been intrigued by Moly bullets and have bought them before. I got this email from a club member and decided to try the HBN powder, it was very cheap. I never noticed my scores or confidence level going through the roof that would be "Magic".
MOLYBDENUM DISULFIDE AND HEXAGONAL BORON NITRIDE LOW FRICTION COATING OF BULLETS
In the early 1990s coating bullets with Molybenum Disulfide became widespread. A Model 70 Winchester rifle of mine had a barrel that would begin to shoot bigger groups and change zeroes after firing 60 to 70 rounds in a rifle match. With Molycoated bullets the zeroes and group sizes were still constant after shooting many more rounds. How many more was never determined because the bore was cleaned after every match or shooting session. More powder is needed with coated bullets for the same velocity as naked bullets but higher velocities are possible with safe pressures. The limit is case capacity with slower burning powders.
Available for coating was a regular, “thick,” Thumblers Tumbler and a “thin” Tumbler donated by a friend. Both have hexagonal bodies with circular flanges that allow rotation. Lyman Media is used in the thin Tumbler to degrease naked bullets. It might be that the surface of a bullet is “prepared” to more readily accept the Moly coating by the tumbling. A couple of hours do the job. A plastic dish or shallow bowl, a sort of sieve with slots in the bottom is used to separate the bullets from the media.
Steel shot with a diameter of about two tenths of an inch is used in the thick Tumbler. Not much Moly powder is need to coat a couple of hundred bullets after the shot has been used at least once. Tumbling usually takes about three hours. The shallow bowl is used to separate the bullets from the shot when coating .30 caliber bullets. The slots are too big for .22 bullets and an electromagnet is needed to separate them from the shot, a cumbersome and messy operation.
At one time several thicknesses of paper towel under a batch of newly coated bullets and several thickness on top and “worried” around were used to remove excess Moly and “polish” the coating. That has been changed. Newly coated bullets are now “massaged” in an old and thick sock to polish.
One drawback with Moly is that a clean barrel needs from a few shots to a dozen shots before the bore is sufficiently recoated to make the zero and group size settle down. A friend over cleans barrels until a patch comes out pristine white. He went back to naked bullets to eliminate having to shoot to recoat.
Some people recommend a thin Carnauba wax coating over the Moly. This makes the bullets less messy to handle. Lapua (or was it Norma?) claims that coating increases ballistic coefficients and wax coating increases that ballistic coefficient a bit. I don’t add wax to Molycoated bullets. I’ve made wooden bullet “tweezers.” With them I can pick that last bullet from a box. I use a seating die that has a side port. With the tweezers I can pick up a bullet and put it in the seating die port without handling the bullet. In fact, from the time that naked bullets are poured out of the box into the thin degreasing Tumbler until a cartridge is loaded into a rifle chamber, the bullets are never touched by human fingers.
Several years ago I began to coat bullets with Hexagonal Boron Nitride (HBN) powder. About the same time I became afflicted with atrial fibrillation. That gave me a pulse rate in the 90s with an irregular heart beat like Morse code. I couldn’t walk a hundred yards to put up targets and return to the firing line without feeling like I needed to lie down. A little over a year ago I had a procedure at Heart Hospital in Oklahoma City that has apparently fixed that problem and my pulse rate is back to a regular 60. I hadn’t shot HBN coated bullets enough to learn how many fewer shots are needed to condition a clean bore, which is one of the claims about the benefits of HBN over Moly
Coating bullets with HBN has been resumed at the Duncan, Oklahoma White House. Naked bullets are degreased in the thin Tumbler as before. Steel shot is not used in the thick Tumbler to apply the HBN coating. Degreased bullets are put in a plastic Ovaltine jar with a closed lid along with a small amount of HBN powder. The plastic jar is an almost perfect fit across the flats of the thick Tumbler. Tumbling of a couple of hours gives a good coating. Massaging in a sock removes excess HBN powder and polishes the coating. The HBN coating procedure is a lot less messy than coating with Moly.
It’s probably feasible to partially fill the space inside the thick Tumbler not occupied by the Ovaltine jar, with Lyman Media, and degrease some bullets while coating others.
Bullets that had previously been Molycoated have had that coating removed in the thin degreasing Tumbler and the newly naked bullets coated with HBN. Molycoated bullets have been pulled from loaded ammo and the bullets recoated with HBN. There seems to be no difference in the coatings of new bullets and recoated bullets.
One of the benefits of coated bullets is that a bullet positioned slightly off alignment with the start of the rifling will more easily tend to align itself with the bore when fired. The nose of a bullet aligned with the center of the bore does not follow a helical path up the barrel and is more accurate. Maybe coating bullets does enhance accuracy.
My son, the chemist, has said that the crystalline structures of Moly and HBN are similar, if not identical. That structure is what makes the coatings slippery.
As to the “slipperiness” of coated bullets? A loaded cartridge with a Molycoated bullet can easily be picked up with the thumb and trigger finger grasping the ogive of the bullet. With a bullet coated with HBN this is very difficult to do.
With the possible and maybe probable increase in the Ballistic Coefficient and accuracy of coated bullets I believe that coating bullets is worth the trouble and that coating with HBN is preferable to Moly coating.
James S. White
Jim White was a young Marine at Okinawa, wounded by a single bullet through both knees. He retired from Halliburton after many years as an engineer. Distinguished, President's 100, many trips to Camp Perry.
In closing, It most likely is not worth it. I will still coat Match bullets, because I have enough of it to last 3 life times. To me since I am set up to do it, it is not the hassle one might assume and deep inside it is like looking at the old Moly bullets I used to want to buy. (Sigh....) Magic...
