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December 10th, 2024
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.
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October 17th, 2024
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).
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).
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August 20th, 2024
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.
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October 27th, 2022
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.
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October 29th, 2019
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.
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September 8th, 2016
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.
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September 8th, 2014
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.
Moly and WS2 both have their fans, but in the last couple of years, some 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.
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 Kb>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.
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:
Momentive Performance Materials
www.Momentive.com
Sales Contact: Robert Bell
Sales Email: robert.bell [at] momentive.com
Sales Phone: Robert Bell, (980) 231-5404
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September 24th, 2012
Gear Review by Boyd Allen
Just about everyone knows that Wilson and Redding make neck-sizing bushings. But few shooters seem to be aware that RCBS produces bushings. In fact, RCBS does make quality neck-sizing bushings, including very nice Tungsten Disulfide-coated bushings.
As a companion product for their Gold Medal bushing-style dies, RCBS produces its own line of sizing bushings, that have a couple of notable features. First, along with plain steel bushings, RCBS offers bushings with a distinctive, dark gray Tungsten Disulfide (WS2) anti-friction coating. Redding offers bushings in bare “white” steel or with a gold-colored Titanium-Nitride anti-friction coating. Wilson bushings are plain steel with a shiny silver finish. Though the Redding and Wilson plain steel bushings may look like stainless, remember that these un-coated bushings need to be kept oiled or they WILL rust. In normal use, you shouldn’t have to worry about rust on the Tungsten Disulfide-coated RCBS bushings.
Comparing coated bushings, Redding’s gold TiN-coated bushings look pretty, but the WS2 anti-friction coating on RCBS bushings seems to work as well. Tungsten Disulfide (WS2) has an extremely low coefficient of friction — 0.03 compared to 0.6 for Titanium Nitride. Accordingly, the RCBS WS2-coated bushings can work with minimal neck lubrication. When I actually sized necks with the RCBS WS2-coated bushings, the “smoothness” of the neck-sizing operation seemed on a par with other quality, coated bushings.
Another notable difference with the RCBS bushings (compared to other brands) is that RCBS stamps the bushing size onto the outside of the bushing, rather than on the top. RCBS puts the bushing diameter on a reduced-diameter band that runs around the circumference of each RCBS bushing. I think that this is a good idea because it eliminates the possibility that raised edges from the stamping itself might interfere with proper bushing alignment*. (Remember that the top of the bushing — where size marks are stamped by other bushing-makers — contacts the retaining cap in the die during sizing.) Putting the size marks on the outside also makes it easy to distinguish RCBS bushings from other bushing brands.
The other feature that I like is the shape of the entry chamfer on the bottom of the RCBS bushing. This chamfer is large and angular, rather than curved. This is only a guess, but I think that it may do a better job of letting the bushing align itself with the case as it is inserted into the die, and do a better job on brass from chambers that allow more neck expansion. (The picture shows the smaller chamfer at the top of the bushing.)
That about wraps it up, with the exception of one small point. While MidwayUSA has a wide selection of RCBS bushings, other retailers need to do a better job of stocking these bushings. I got mine from RCBS, but you may have trouble finding them in many online catalogs, or on dealers’ shelves. Hopefully this small review will help to increase awareness of RCBS bushings, and more retailers will carry them.
*As you probably know, stamping displaces metal, some of which is raised above the level of the surface that was stamped. Although it can be argued that shooters have gotten some pretty spectacular results in spite of any cocking of neck bushings caused by their being stamped on top, I am sure that a lot of us would prefer to have things as straight as they can be, and moving the stamping to a recessed band that runs around the outside of the bushing helps accomplish this.
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March 28th, 2010
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.
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