Guide to Bullet Coating

Coating Bullets with Tungsten Disulfide

For fans of coated bullets, here is a step-by-step bullet-coating guide. This article explains how to apply dry lubricants to jacketed bullets using two methods. In Part I of this article, Kevin Osborne shows how to coat bullets with a vibratory tumbler.

There are other ways to coat bullets, but both these methods work. The first method is ideal for shooters on a tight budget. Most shooters already own a vibratory tumbler, and the small containers can be obtained for little or no money.

Tungsten Disulfide is also known as “WS2”, or “Danzac”. (Danzac was a trade name for a Tungsten Disulfide-based product; Danzac is no longer produced, but many people still use this term.) Tungsten Disulfide seems to possess most of the benefits of Moly, but with a higher temp rating. Some people feel WS2 is easier to remove from a barrel than Moly because it does not build up as thickly. Both Moly and WS2 contain sulfur, which can cause corrosion if free sulfides combine with moisture.

To Coat or Not to Coat?
Should you coat your bullets at all? That remains a hotly debated question. We won’t attempt to answer that here. Many shooters, particularly varminters and High Power shooters, believe that application of WS2 helps their shooting. High Power shooters are required to shoot long strings of fire with no opportunity to clean. Varminters typically fire a lot of rounds at very high velocities. If coated bullets can reduce copper and powder fouling, that allows a varminter to spend more time hunting and less time cleaning. Some other shooters coat their bullets because they believe this reduces friction and heat in the barrel, which should extend barrel life.

If coating bullets with dry lubricants can reduce friction/heat, extend cleaning intervals and, possibly, make barrels last longer, then why doesn’t everyone shoot coated bullets?

Well, there is no free lunch. By reducing friction, bullet coating has the effect of reducing pressures in your barrel. This means that you’ll get less velocity with coated bullets than naked bullets, given the same powder load. Anti-friction coatings are Speed Robbers. You can expect to lose 20-80 fps after coating your bullets, maybe more with large cartridges and bullets with long bearing surfaces. In order to get back to the velocity you had before coating your bullets, you’ll need to adjust the powder load upwards–perhaps a half-grain or more. That’s not a problem … IF you have extra capacity in your case. If you’ve already maxed out your case capacity, you may need to change powders, or just accept the slower velocity as the “price” of coating your bullets.

WARNING!! Do NOT automatically increase your powder charge after coating your bullets. As with all reloading, start with a KNOWN SAFE MODERATE LOAD for naked (un-coated) bullets of the same type/weight and work up in small increments, checking for pressure.


Coating Bullets with Tungsten WS2

by Kevin Osborne

In this section, I’ll show how I coat my bullets with Tungsten Disulfide (WS2). Step by step, you’ll see a batch of 34gr, 20-caliber Dogtown bullets being coated, start to finish. Here they are fresh out of the box:

STEP ONE: Organize Gear and Components
I use a standard, inexpensive vibratory tumbler. My unit is a Frankford Arsenal Quick-N-EZ. I use two sizes of pill bottles. The shorter bottles will hold one hundred 20-caliber bullets and the larger will accommodate 200 bullets. NOTE: These quantities are for small, 20-caliber bullets. The capacity would be less for larger calibers.

STEP TWO: Add Pellets
You need some metal pellets to impact-plate the dry lubricant on to your bullets. For burnishing media I use standard .177 BBs. Any brand will work (but see comment below). With the small bottles I put 3/8″ worth of BBs in the base of the bottle. The larger bottles get a 1/2″ layer. Uniform steel balls probably work best. Consider also that steel shot can be separated from the bullets with a large magnet.

STEP THREE: Add Dry Lube Powder
After adding bullets and BBs, drop in the Tungsten WS2. NOTE: With fresh burnishing media (BBs) you need to put in extra WS2 because you will be coating the BBs as well as the bullets! Just dump it on top of the bullets, close the bottle, give it a few shakes by hand for good luck, then drop it in the tumbler.

STEP FOUR: Tumble Containers
You will want to tumble your bullets for at least 30 minutes. To verify if your bottles are rotating (like the drum in a clothes dryer), leave the tops of the pill bottles exposed in the bowl so you can see them spin. NOTE: Some folks will tumble their brass at the same time. I have gone away from tumbling brass while coating bullets as I think it was interfering with the rotation of the bottles. [Editor’s NOTE: Some shooters like to tumble for as long as 3 hours. The correct time will depend on your tumbler and the type of bullets.

STEP FIVE: Inspect Your Bullets
Pull one coated bullet from your tumble bottle and polish the bullet by hand. If it is coated to your liking, you can polish the rest of them. If the sample is not coated evenly, switch on the machine and tumble the bullets some more.

STEP SIX: Move to Polish Container and Shake
I use a RubberMaid-style container for the first polish. This will be bigger than your tumbling bottle. Line the container with paper towels and fill with bullets from your tumbling bottle. To cut down on the mess and to not waste WS2, I pull them from the bottles with a pair of tweezers. This keeps your hands clean. If you have access to a paper shredder, shred some newspaper and put it in with the bullets. If you don’t have a shredder, just use the paper towel. Put the lid on and shake the bullets for about 30 seconds.

At this point you could call it good, but you will end up with black hands after reloading. (This is not a problem if you use gloves).

STEP SEVEN: Final Polish
I like to give the bullets one final, manual polish. You will need to get an FPD (Final Polish Device). I simply put the coated bullets in the sock and shake for another 30 seconds or so.

The Final Result–Coated Bullets
The entire process of bullet coating with WS2 can be accomplished in an hour or less. It can take more time if you clean your bullets. To date the only bullets I have cleaned were some old tarnished hollow points for my 264 Magnum. All new bullets I do go right in from the box. However, I know other shooters prefer to clean their bullets first.