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Moly Coat?

Discussion in 'Handloading and Reloading' started by atlanticfire, Dec 6, 2009.

  1. atlanticfire

    atlanticfire Well-Known Member

    Hello Fellas.
    Was at a range this weekend. interesting place. I don't believe they had any rifles in there from this century.:uhoh: But anyway. .. They had boxes of bullets. When I say boxes I mean like small pallet loads.:what: I have no Idea where they came from, and I didn't ask. I did find dozens of boxes of Sierra Game and Match kings, which I generally use. From 165 GR to 200gr. But here is the question. The boxes where opened and it appears that someone has moly coated all of them. Now they do look good, no visible signs of anything bad and the moly coat appear to be well done. I suspect this is when they had some many or this old guy got tons of bullets that are not desired. So what do you think? If I can pick them up dirt cheap would it be worth it, or is it just better to stay away?
  2. longdayjake

    longdayjake Well-Known Member

    Never used moly but I have heard that if you use it once you should always stick to it or you will get crappy results from any bullet you shoot.
  3. Borg

    Borg Well-Known Member

    Not quite true.
    When switching back and forth with moly. it takes 10-15 rnds to settle down, going either way.
  4. zfk55

    zfk55 Well-Known Member

    Custom made tumbler top for simultaneous Moly (or hBN) impact coating and brass cleaning.

    I took a piece of 1/2" thick Sintra (expanded PVC), routed a channel on the back to fit exactly over the rim of a tumbler, cut two holes the exact size of the lower 1/3rd of two plastic jars and cut a center hole for the shaft and wing-nut.
    Slide the jars in till they're tight, add the .177 steel balls and impact coat. You can even leave the media in the bowl if you want to clean brass at the same time.
    This setup keeps the center of gravity low and the shaking is much harder and sharper without the cushion of small jars floating in the media.





    Tumbler with jars removed. The media is inside so we can do brass at the same time as impact coating.


    If you're truly interested in impact coating I can take some time and explain.

    Last edited: Dec 11, 2009
  5. Hey_Allen

    Hey_Allen Well-Known Member


    This looks like an interesting project, and one that should probably have a thread documenting it!

    I'm interested in more info, in PM if not in this thread.

  6. zfk55

    zfk55 Well-Known Member

    Glad to do it. It'll take a bit of time to assemble, but it is interesting.

  7. atlanticfire

    atlanticfire Well-Known Member

    Wow! Cool project. I guess I'm also hungry for information about the pluses of moly coating. What is its effect on a rifle barrel? Once I start using them will it be necessary for accuracy to only use moly coated? I see that you have spent time and a lot of though into your operation and would like to know what took you the route of moly coating? Sorry for all the questions, but I’m like a sponge when it comes to this kind of stuff.
    Last edited: Dec 7, 2009
  8. Seedtick

    Seedtick Well-Known Member


    Sir, that is one fine looking rig you've built!

    I am looking forward to your 'coating' post as well.


  9. zfk55

    zfk55 Well-Known Member

    Ok. We'll take this one step at a time, and it may take a couple of days for me to get a few missing photos, but this is the start.
    I'll keep adding to this thread as I'm able.
    This process applys to both Moly and hBN impact coating of projectiles. I'll explain the differences, pros and cons. With hBN there are literally no cons at all. With Moly, there are a couple. Both are intended to extend barrel life, but the hBN beats Moly but quite a margin.

    Bullet prep before hBN impact coating.

    The steel balls are .177 BBs. The projectiles here are 175gr Sierra Matchlings.

    Now it begins.
    Ball and Bullet washing.
    Hot, soapy water.




    Now they dry overnight on a Terry Towel.

    The steel balls and bullets were brand new right out of the box, but after washing, the water was grey and dirty.

    More to come with the next process.

    Last edited: Dec 8, 2009
  10. zfk55

    zfk55 Well-Known Member

    I'll most certainly cover Moly, but we use Moly for one, solitary, dedicated rifle, and that's because the bore is 17-4 Stainless Steel and electro polished. Were it not for that we'd not be using Moly at all. hBN is far superior, and if you're serious about this, I'll ask that you do a bit of reading before we continue. I'll not ask that you read the entire patent, but I'll post excerpts.

    If you're as dedicated as we are, this is the patent itself with all of the dry content.


    These are the important excerpts you'll need to understand before you continue.

    BTW........ This is a supposedly protected David Tubb secret for both Moly and hBN, but we've stumbled on it or at least our end results are as good as his.
    Our Moly coating can't be scratched off the projectile surface wtih your fingernail and is a perfectly smooth, even coating.
    Our hBN process, oddly enough, follows pretty close to the Moly process.


    Secondary Ion Mass Spectrometry (SIMS) testing performed on the surfaces of the internal bore of gun barrels shows that the boron nitride powder used in accordance with the present invention results in the ceramic powder particulates beingclearly embedded within the grain boundaries of the metal gun barrel. These test results show that burnishing sub-micron particulate ceramic is effective, and that continued firing of uncoated bullets will continue to experience the advantages of thepresent invention for an extended period of time. Such testing also shows that excessively coating boron nitride powder onto bullets provides erratic results and sometimes no velocity improvement. Thinner coating on the bullets provides more consistent velocity improvement.

    "This is achieved by the ceramic dry lubricant providing reduced friction and improved bullet seal, reducing vibration or "chatter" of a bullet traveling down the gun barrel. Another advantage is the elimination of gun barrel corrosion. Corrosion or rust can only begin in metal grain boundaries, which, according to the present invention, are filled with the sub-micron sized particles of the ceramic dry lubricant. Anotheradvantage is increased accuracy. This results because the bullet time-to-target is reduced as a result of increased muzzle velocity. Accuracy is increased also due to the reduced stress caused by reduction of friction and heat. Accuracy is also increased as a result of a more consistent bullet seal achieved by the present invention. A final advantage is the inexpensive nature of the present invention, which can be practiced in the field on existing gun barrels."

    A 0.308 caliber firearm was loaded with a series of boron nitride powder-coated rounds as well as a series of uncoated rounds. The velocity of the rounds exiting the barrel of the firearm as well as the temperature of the firearm barrel weremeasured in feet per second by a chronograph and in degrees Fahrenheit, respectively, to determine velocity and temperature effects of metal oxide powder implantation by burnishing the internal bore of the barrel with a suitable dry lubricating ceramicparticulate. See FIG. 7 for specific results.
    Summary of results
    20 uncoated rounds had an average muzzle velocity of 2368 feet per second and a maximum barrel temperature of 120° Fahrenheit. A first set of 20 boron nitride powder-coated rounds had an average muzzle velocity of 2732 feet per secondand a maximum barrel temperature of 138° Fahrenheit. A second set of 20 boron nitride powder-coated rounds had an average muzzle velocity of 2719 feet per second and a maximum barrel temperature of 150° Fahrenheit. The average gain inmuzzle velocity by coating rounds with boron nitride powder was 157 feet per second. The average gain in barrel temperature was 18° Fahrenheit.
    The temperature increase was likely caused as a result of the particulate being burnished into the internal bore, representing the thermal work being bestowed upon the barrel. The likelihood is that barrel temperature will be reduced as theinternal bore is further treated with particulate.


    This will be enough for your continuing with the process.
    More to come.

  11. zfk55

    zfk55 Well-Known Member

    Ok, this will apply to both Moly and hBN prep. You have the .177 BBs washed. Plour them in the plastic container filling it to the 1/3rd jar capacity. If its to be hBN, add a nominal 10 grains of hBN to the jars and seal tightly.
    If its to be Moly, add two heaping Teaspoons.

    Remember that hBN is a negative 5 micron size, so use good jars with tight lids. The smaller P-nut butter jars pictured here are ok.


    Unless you make a custom top for a standard case tumbler you'll need to place them on their sides with dense foam padding bottom, sides and top.



    Put enough padding on the top, covering the jars so as to compress them slightly preventing free movement within the tumbler.


    Turn on the tumbler and leave it to work for a full three hours.

    Secret #1: Do not place the plastic jars in a tumbler filled with tumbling media. It softens the impact within the jars. You do want a relativley hard, sharp impact for positive coating.

  12. zfk55

    zfk55 Well-Known Member

    Now we'll add the projectiles.
    With hBN, open the jars slowwwwly. If you can "smell" the hBN, it means you're breathing in the powder. Wear a mask. For Moly, just handle it slowly and carefully. Moly is incredibly messy, so wear latex or similar gloves. You're going to have black all over the place if you drop the jar, and it won't clean up easily.

    If your jar is one from the pharmacy that measures about 3"x4.5" and is 1/3rd full of impact coated BBs, you can add 50 .30 cal 175gr projectiles or 100 55gr .224 projectiles.
    For hBN add 4gr of hBN and close the lids. For Molyl, add another heaping teaspoon and close the lids.

    Place back into the padded tumbler and run for three full hours.

    Separate the projectiles from the BBs with a mesh screen large enough to easily pass the BBs. (This one is not for Moly separation)


    We use a quick release magnet to collect the BBs and return them to the jars.


    When the projectiles come out of the jars they'll look somewhat fuzzy, like this.


    Roll them around in a thick Terry towel, wipe them off and they'll look satin, like this.


    Moly pics later, and the Moly finish is quite different from the hBN finish. Do not try rolling Moly coated projectiles around in a towel. You'll get a messy surprise.

    Last edited: Dec 9, 2009
  13. zfk55

    zfk55 Well-Known Member

    For the moment...... Do not use the same screen for Moly as you do for hBN. Get a seperate one and store it in a plastic sealable tie bag.
    I'll post pics when I take some new ones, but the correct finish process for the moly coated projectiles is to place them in a small tumbler with corncob media for 10 minutes, and not one second longer.
    If you've done it all correctly, the finished projectiles will be a solid, deep silver-gray and you won't be able to scratch the Moly from the surface easily at all.
    Pics when I do the next batch.

    For the moment, they should look like this.


  14. NoAlibi

    NoAlibi Well-Known Member

    zfk55 - Why are the steel BBs necessary? Wouldn't the impact of the bullets against each other suffice?
  15. tommyintx

    tommyintx Well-Known Member

    please include your source for molybdenum disulfate and hBN. i used to get "technical grade moly" from midway but since have found no reasonably priced sources. my 223 bolt loves moly 40 vmax's and btip's... 27.0 benchmark =3800 fps (not factoring in moly.. need to get the chrony out.. but i'm going to wait until it's warmer outside! [​IMG]
  16. zfk55

    zfk55 Well-Known Member

    Best price for Moly is here..... http://www.micronmetals.com/ And ask for Lab Grade, 99.9% 3 to 5 micron Moly.

    Best price for hexagonal Boron Nitride is here.... Negative 5 micron works fine. http://sandblastingabrasives.com/contact-us.html?action=success

    The .177 steel BBs are necessary for complete imact of the projectiles. Essentially its the difference between screwin' around with the process and doing it correctly and completely. The contact surface of the coated BBs is tiny, and repeated, harsh contact is what gives you a complete coverage of the projectiles.

    I'll continue with pics and procedure the next Moly run I do. Probably friday night or saturday morning.

  17. tommyintx

    tommyintx Well-Known Member

    I have had pretty good luck moly coating with lead #8 shotgun shot, with the midway moly, in a small midway tumbler i never use anymore.

    +1 on getting some purple nitrile gloves if you don't want gunmetal gray hands forever.
  18. Maj Dad

    Maj Dad Well-Known Member

    New Project

    zfk55, this has really caught my attention. I have a Ruger M77 old model in 6mm Rem that I almost used moly in some years back in New Mexico, but I think I will give the hBN a try. It will shoot into 1/2" at 200 yds with some R19 loads and medium wt bullets, and is my test bed for a lot of accuracy piddling. Do you use bearing grade .177 bbs or just bb gun variety?
    Thanks for sharing this wealth of information!
    Maj Dad
  19. zfk55

    zfk55 Well-Known Member

    BB gun type works great. We use them for both hBN and Moly.
    The hBN process is a huge deal for us. A large number of our rifles are Swiss rifles and the barrels are definitely not easily replaceable, particularly the zfk55. This one.


    Doubleing and tripleing barrel life is the main thing, but the increased tightening of groups is rather amazing.

    Barrel prep for hBN is very important, and I'll cover that next.

    Last edited: Dec 11, 2009
  20. zfk55

    zfk55 Well-Known Member

    Clean the bore/chamber/throat with Wipe Out or a like non-ammonia based copper remover. Use a carbon remover specific like Montana Extreme or a like carbon remover in the chamber and throat.

    If you have one, inspect the bore for complete copper removal with a bore scope.


    If not, be safe and use the Wipe Out with a nylon bristle brush, working up a heavy foam and let stand for a few hours.

    Dry clean completley with patches or clean swabs.
    Take a new .30 caliber cotton swab, or take your old ones and run them through the laundry or dishwasher. Dry completely.

    Short switch back to square one:
    You'll get your hBN in a container with a plastic, tape seal around the outside. Open it with extreme care and only long enough to fill a small, sealable pill bottle 1/3rd full. Re-seal the container immediately. Re-apply the exterior tape seal fully and tightly. Store at room temps in a secure place. Spill that container in a room in the house and your wife will be using a bat on you for weeks to come.
    (No, I didn't, and my wife uses Darning Eggs instead of bats)

    Screw the swab to the end of a cleaning rod just long enough to run the bore, open the hBN pill bottle, carefully roll the swab in the hBN, (close the hBN bottle immediately) insert into the bore from the breech end if possible. If your rifle won't acommodate taht, run it from the muzzle end. Go all the way through and then work it gently back and forth while slowly withdrawing the swab.
    Once its out, leave it alone. The first few impact coated projectiles fired through the bore will do the ceramic coating for you, and that's it. You've done it. From that point on fire only impact coated projectiles through that rifle. Cleaning is done with dry patches, no chemicals at all.
    For the chamber/throat area, use the right sized swab to fit into each and use Montana Extreme or a like carbon remover. Don't run any cleaning solvents down the bore.
    If you feel the need to do that once in a while, cool...... but make sure you use the clean swab and hBN process again. It only takes a few minutes. I unscrew the swab and keep it inside the pill bottle so that it remains uncontaiminated.
    To understand how it works, save me a bunch of typing and read the patent.

    I'll post process pics of the Moly setup on the weekend.


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