September 26th, 2018

Safety Tip for Loading With Coated Bullets

Moly Danzac Bullet Coating Anti-friction HBN

Coating bullets with a friction-reducing compound such as Molybdenum Disulfide (Moly) offers potential benefits, including reduced barrel heat, and being able to shoot longer strings of fire between bore cleanings. One of the effects of reduced friction can be the lessening of internal barrel pressures. This, in turn, means that coated bullets may run slower than naked bullets (with charges held equal). To restore velocities, shooters running coated bullets are inclined to “bump up” the load — but you need to be cautious.

Be Careful When Increasing Loads for Coated Bullets
We caution shooters that when your start out with coated bullets in a “fresh barrel” you should NOT immediately raise the charge weight. It may take a couple dozen coated rounds before the anti-friction coating is distributed through the bore, and you really start to see the reduced pressures. Some guys will automatically add a grain or so to recommended “naked” bullet charge weights when they shoot coated bullets. That’s a risky undertaking.

We recommend that you use “naked” bullet loads for the first dozen coated rounds through a new barrel. Use a chronograph and monitor velocities. It may take up to 30 rounds before you see a reduction in velocity of 30-50 fps that indicates that your anti-friction coating is fully effective.

We have a friend who was recently testing moly-coated 6mm bullets in a 6-6.5×47. Moly had not been used in the barrel before. Our friend had added a grain to his “naked” bullet load, thinking that would compensate for the predicted lower pressures. What he found instead was that his loads were WAY too hot initially. It took 30+ moly-coated rounds through the bore before he saw his velocities drop — a sign that the pressure had lowered due to the moly. For the rounds fired before that point his pressures were too high, and he ended up tossing some expensive Lapua brass into the trash because the primer pockets had expanded excessively.

LESSON: Start low, even with coated bullets. Don’t increase your charge weights (over naked bullet loads) until you have clear evidence of lower pressure and reduced velocity.

Procedure After Barrel Cleaning
If you shoot Moly, and clean the barrel aggressively after a match, you may want to shoot a dozen coated “foulers” before starting your record string. Robert Whitley, who has used Moly in some of his rifles, tells us he liked to have 10-15 coated rounds through the bore before commencing record fire. In a “squeaky-clean” bore, you won’t get the full “benefits” of moly immediately.

To learn more about the properties of dry lubricants for bullets, read our Guide to Coating Bullets. This covers the three most popular bullet coatings: Molybdenum Disulfide (Moly), Tungsten Disulfide (WS2 or ‘Danzac’), and Hexagonal Boron Nitride (HBN). The article discusses the pros and cons of the different bullet coatings and offers step-by-step, illustrated instructions on how to coat your bullets using a tumbler.

Permalink Reloading, Tech Tip 3 Comments »
February 17th, 2018

Hexagonal Boron Nitride (HBN) for Bullet Coating

hexagonal Boron nitride bullets

For years, many shooters have coated bullets with Moly (molybdenum disulfide) or Danzac (tungsten disulfide or “WS2″). The idea was to reduce friction between bullets and barrel. In theory, this could lengthen barrel life and extend the number of rounds a shooter can fire between cleanings.

hexagonal Boron nitride bullets

Moly and WS2 both have their fans, but in recent years, many guys have switched to Hexagonal Boron Nitride (HBN), another dry lubricant. The advantage of HBN is that it won’t combine with moisture to create harmful acids. HBN is very slippery and it goes on clear, so it doesn’t leave a dirty mess on your hands or loading bench. Typically, HBN is applied via impact plating (tumbling), just as with Moly.

Good Source for Hexagonal Boron Nitride (HBN)
Paul Becigneul (aka PBike in our Forum) has been using HBN for many years with good results. He obtains his HBN from Momentive Performance Materials:

HBM boron nitride source momentive hexagonal bullet coatingMomentive Performance Materials
www.Momentive.com

Sales Contact: Robert Bell
Sales Email: robert.bell [at] momentive.com
Sales Phone: Robert Bell, (980) 231-5404

HBN Results — Both on Bullets and Barrel Bores
Many folks have asked, “Does Hexagonal Boron Nitride really work?” You’ll find answers to that and many other questions on gunsmith Stan Ware’s popular Bench-Talk.com Blog. There Paul Becigneul (aka Pbike) gives a detailed run-down on HBN use, comparing it to other friction-reducers. Paul also discusses the use of HBN in suspension to pre-coat the inside of barrels. Paul observes:

We coated our bullets … how we had been coating with WS2. Now our bullets have a slightly white sheen to them with kind of like a pearl coat. They are so slippery it takes a little practice to pick them up and not drop them on the trailer floor. What have we noticed down range? Nothing different from WS2 other than the black ring on your target around the bullet hole is now white or nonexistent. Our barrels clean just as clean as with WS2. Your hands aren’t black at the end of the day of shooting and that might be the most important part.

Interestingly, Becigneul decided to try a solution of HBN in alcohol, to pre-coat the inside of barrels. Paul had previously used a compound called Penephite to coat the inside of his barrels after cleaning. Paul explains:

If Penephite was used because it was slippery wouldn’t HBN be better? … We called Momentive again [our source for HBN], and talked about mixing HBN and 90% alcohol for a suspension agent to pre-lube our barrels. He though it sounded great but that the AC6111 Grade HBN would be better for this use. It would stand up in the alcohol suspension and cling to the barrel when passed through on a patch. We got some and mixed it in alcohol 90%. We use about one teaspoon in 16 ounces of alcohol.

We started using it this fall and what we have noticed is that now that first shot fired out of a clean and pre-lubed barrel can be trusted as the true impact point. We use tuners so now I got to the line, fire two shots judge my group for vertical, adjust the tuner as needed or not, and after tune has been achieved go to my record targets. This use has saved us in time at the bench and bullets in the backstop.

You really should read the whole article by Becigneul. He discusses the use of barrel lubes such as Penephite and “Lock-Ease” in some detail. Paul also provides links to HBN vendors and to the Material Safety Data Sheets (MSDS) for the various compounds he tested.

Permalink Reloading, Tech Tip 3 Comments »
March 30th, 2017

How to Coat Bullets Using a Vibratory Tumbler

While “naked” bullets are just fine for most applications, some shooters like to put a friction-reducing coating on their projectiles. Coating bullets can benefit guys who run very high round counts between barrel cleanings. Reader Mike Etzel has come up with a simple, cost-effective way to apply HBN, Moly, or Danzac (WS2) coatings to your bullets. And you won’t need any expensive gear other than your regular vibratory tumbler and some small plastic containers.

Mike explains: “For a number of years I have been using a very convenient way of coating my projectiles with DANZAC in a tumbler. Instead of using a separate tumbler filled with DANZAC and stainless steel balls for coating applications, use small resealable plastic cake or pudding cups filled with stainless balls and DANZAC. Each cup will accommodate between 20 to 70 projectiles depending on caliber once the polishing balls and DANZAC are added. When I need to polish some cases, I insert the sealable plastic container(s) into the polishing material in the tumbler, add cases to the media, and in the process clean cases and coat the projectiles simultaneously in one tumbler. This does two operations in one session, saving on time and resources.”

While Mike uses DANZAC (Tungsten DiSulfide or WS2), you can use the same impact-tumbling method to moly-coat your bullets, or to apply HBN (Hexagonal Boron Nitride).

bullet coatings source hbn moly danzac

TIPS for COATING your BULLETS, by GS Arizona

1. Start with Clean Bullets. This is simple enough, but some people overlook it and others overdo it. Get the bullets out of the box, wash them with warm water and dish soap and dry them. No need for harsh chemicals, after all, we’re only removing some surface dirt from shipping and maybe some left over lanolin from the forming process. Don’t handle them with bare hands once they’re clean, your skin oils will contaminate them.

2. Get Everything Hot — Real Hot. This is probably the single most important element in producing good-looking moly-coated bullets. I put the tumbler, the drum and the bullets out in the sun for at least 30 minutes before starting and then do all the tumbling in direct sunlight. On a summer day in Arizona, everything gets to the point that its uncomfortably hot to handle. If you are tumbling in the winter, you should heat the bullets in some form, a hair dryer can be useful, but they will cool off in the drum if you’re tumbling in cold temperatures. Your best bet is to plan ahead and do your coating in the summer. I coated about 3000 bullets in a couple of days recently to see me through our winter season (we’re a bit reversed from the rest of the country in terms of shooting season).

Permalink Bullets, Brass, Ammo, Reloading 5 Comments »
September 8th, 2016

Reloading Tip for Coated Bullets — Adjust Loads Cautiously

Moly Danzac Bullet Coating Anti-friction HBN

Coating bullets with a friction-reducing compound such as Molybdenum Disulfide (Moly) offers potential benefits, including reduced barrel heat, and being able to shoot longer strings of fire between bore cleanings. One of the effects of reduced friction can be the lessening of internal barrel pressures. This, in turn, means that coated bullets may run slower than naked bullets (with charges held equal). To restore velocities, shooters running coated bullets are inclined to “bump up” the load — but you need to be cautious.

Be Careful When Increasing Loads for Coated Bullets
We caution shooters that when your start out with coated bullets in a “fresh barrel” you should NOT immediately raise the charge weight. It may take a couple dozen coated rounds before the anti-friction coating is distributed through the bore, and you really start to see the reduced pressures. Some guys will automatically add a grain or so to recommended “naked” bullet charge weights when they shoot coated bullets. That’s a risky undertaking.

Instead we recommend that you use “naked” bullet loads for the first dozen coated rounds through a new barrel. Use a chronograph and monitor velocities. It may take up to 30 rounds before you see a reduction in velocity of 30-50 fps that indicates that your anti-friction coating is fully effective.

We have a friend who was recently testing moly-coated 6mm bullets in a 6-6.5×47. Moly had not been used in the barrel before. Our friend had added a grain to his “naked” bullet load, thinking that would compensate for the predicted lower pressures. What he found instead was that his loads were WAY too hot initially. It took 30+ moly-coated rounds through the bore before he saw his velocities drop — a sign that the pressure had lowered due to the moly. For the rounds fired before that point his pressures were too high, and he ended up tossing some expensive Lapua brass into the trash because the primer pockets had expanded excessively.

LESSON: Start low, even with coated bullets. Don’t increase your charge weights (over naked bullet loads) until you have clear evidence of lower pressure and reduced velocity.

Procedure After Barrel Cleaning
If you shoot Moly, and clean the barrel aggressively after a match, you may want to shoot a dozen coated “foulers” before starting your record string. Robert Whitley, who has used Moly in some of his rifles, tells us he liked to have 10-15 coated rounds through the bore before commencing record fire. In a “squeaky-clean” bore, you won’t get the full “benefits” of moly immediately.

To learn more about the properties of dry lubricants for bullets, read our Guide to Coating Bullets. This covers the three most popular bullet coatings: Molybdenum Disulfide (Moly), Tungsten Disulfide (WS2 or ‘Danzac’), and Hexagonal Boron Nitride (HBN). The article discusses the pros and cons of the different bullet coatings and offers step-by-step, illustrated instructions on how to coat your bullets using a tumbler.

Permalink Bullets, Brass, Ammo, Reloading 4 Comments »
June 30th, 2016

Efficient Method for Bullet Coating with Moly, WS2, HBN

Reader Mike Etzel has come up with a simple, cost-effective way to apply moly or danzac coatings to your bullets. And you won’t need any expensive gear other than your regular vibratory tumbler and some small plastic containers.

Mike explains: “For a number of years I have been using a very convenient way of coating my projectiles with DANZAC in a tumbler. Instead of using a separate tumbler filled with DANZAC and stainless steel balls for coating applications, use small resealable plastic cake or pudding cups filled with stainless balls and DANZAC. Each cup will accommodate between 20 to 70 projectiles depending on caliber once the polishing balls and DANZAC are added. When I need to polish some cases, I insert the sealable plastic container(s) into the polishing material in the tumbler, add cases to the media, and in the process clean cases and coat the projectiles simultaneously in one tumbler. This does two operations in one session, saving on time and resources.”

While Mike uses DANZAC (Tungsten DiSulfide or WS2), you can use the same impact-tumbling-in-a-cup method to moly-coat your bullets, or to apply HBN (Hexagonal Boron Nitride).

bullet coatings source hbn moly danzac

TIPS for COATING your BULLETS, by “GS Arizona”

1. Start with Clean Bullets. This is simple enough, but some people overlook it and others overdo it. Get the bullets out of the box, wash them with warm water and dish soap and dry them. No need for harsh chemicals, after all, we’re only removing some surface dirt from shipping and maybe some left over lanolin from the forming process. Don’t handle them with bare hands once they’re clean, your skin oils will contaminate them.

2. Get Everything Hot — Real Hot. This is probably the single most important element in producing good-looking moly-coated bullets. I put the tumbler, the drum and the bullets out in the sun for at least 30 minutes before starting and then do all the tumbling in direct sunlight. On a summer day in Arizona, everything gets to the point that its uncomfortably hot to handle. If you are tumbling in the winter, you should heat the bullets in some form, a hair dryer can be useful, but they will cool off in the drum if you’re tumbling in cold temperatures. Your best bet is to plan ahead and do your coating in the summer. I coated about 3000 bullets in a couple of days recently to see me through our winter season (we’re a bit reversed from the rest of the country in terms of shooting season).

Permalink Bullets, Brass, Ammo, Tech Tip 10 Comments »
March 8th, 2014

Boron Nitride Application Procedures for Bullet-Coating

hexagonal boron nitride bullet coatingIn our article on Bullet Coating we covered the basic principles of applying dry lubricants to “naked” bullets. This article covered the three main coating options: Molybdenum Disulfide (Moly), Tungsten Disulfide (WS2 or “Danzac”), and Hexagonal Boron Nitride (HBN or “White Graphite”). All three compounds can be impact-plated on to bullets with relative ease, using inexpensive equipment. Moly is still the most popular choice, but many more shooters are considering HBN because it is ultra-slippery, it is less messy, and it offers some advantages over Moly or WS2.

After we published our Bullet Coating feature, many readers asked for more info on HBN. Some current moly users had questions about switching over to Boron Nitride. Forum member Larry Medler has published an excellent web article discussing the process of applying 70nm HBN using plastic jars and a Thumler’s rotary tumbler. If you are working with HBN currently, or plan to experiment with Boron Nitride, you should read Medler’s HBN-Coating Article.

CLICK HERE to READ MEDLER HBN ARTICLE

After coating some bullets for his 6XC, Medler seems “sold” on the merits of HBN. Larry writes: “The coating process is much better than Moly — no black mess. My coating process times are the same as 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. So far I am very pleased with my coated bullets’ smoothness and appearance.”

hexagonal boron nitride bullet coating

Field Tests Are Very Promising
Interestingly, Larry’s HBN-coated bullets are shooting flatter, with tighter vertical, than his moly-coated bullets. Since he has also pointed the tips of this batch of bullets, it’s not clear whether the reduced drop is due to the pointing or the HBN coating, but the results are certainly encouraging: “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 15 shots with less than 1.5 inches of vertical which is the best I have ever seen with my rifles. Is that due to the hBN or bullet pointing?”

Photos courtesy Larry Medler, All Rights Reserved

Permalink Bullets, Brass, Ammo, Reloading 11 Comments »