I have just started to by my own equipment but have been loading for for years.
Could someone please explain the benefits of using moly coated bullets as I am just starting to reload for the 204 ruger and they are raving about how clean the bullet is.
Thanks in advance.

Keep the Son in your eyes.

Moly coating is a messy subject. I have shot moly bullets for a long time, and I can probably give you some straight, if complicated, information on the matter. Early development by the late Roger Johnston and worked on by the late Merrill Martin generated some extreme expectations for moly and a gold rush of bad knock-off coating kits supplied with iron-contaminated industrial surplus moly salvaged from metal stamping operations.

I use only impact plated moly coated bullets. Impact plating is the original NECO application process developed by Johnston and Martin. It is licensed to Sierra, Norma, and Berger. Any moly coated bullets you buy from these manufacturers will be good. I won’t vouch for any others. The moly used in the NECO process is a high purity laboratory grade molybdenum disulphide powder applied by lightly pounding it into the bullet jacket metal with steel ball bearings that have been coated with it in advance. This is followed by similarly plating the bullets with powdered carnauba wax, which keeps the moly from rubbing off on everything.

There have been rumors of moly deposits causing barrel corrosion. The claim came from just one source, and is a theoretical possibility, but appears only to occur when iron contaminated surplus moly has been employed. I have never seen it, despite some moly having been left in one of my 4130 steel barrels for many years. I doubt Sierra or Norma or Berger would continue to offer these if they were getting negative feedback on barrel life.

Where the process shines is in reducing copper jacket fouling in rifle bores that have to fire a lot of rounds between cleanings. Back before I learned about firelapping, I had a match accurized M1 Garand that absolutely would not shoot the national match course (50 rounds) without the accuracy deteriorating during the last 20 rounds (600 yard slow fire). Fouling built up so heavily, that I would be in for hours of working with Sweet’s 7.62 to remove it. After switching to impact plated moly bullets, the problem went away, and the gun could make it through a full service rifle match of 80 rounds + sighters with no problem.

A contrary cleaning issue is a tendency for a build-up of moly and carbon fouling to form at the end of the neck portion of the rifle chamber where it forms a corner with the mouth of the freebore. In very tight chambers with short throats, this build-up has been reported to cause a chamber pressure increase by jamming the end of the case neck. This should not happen if you keep your cases consistently trimmed, but a long neck has the potential to interact unfavorably with the deposit. Normal cleaning will not remove this hard deposit, as I have observed with my borescope. I used to make chamber neck cleaning tools on my lathe that would cut this deposit away. I have subsequently found that Slip 2000 Carbon Killer and Gunzilla both soften the deposit enough so that it comes out with normal cleaning. My old cleaning routine for a lapped bore was just Kroil and Iosso Bore Cleaner and more Kroil, but I now follow the initial two patches of Kroil with two patches of either Carbon Killer or Gunzilla, allowing each time to soak. Gunzilla is the slower working of the two, so I use it when I am going to leave the stuff soaking overnight.

Accuracy: In handguns I can see no difference between moly-coated and plain bullets. In rifles, at shorter ranges, moly bullets have no more accuracy than plain bullets in a fairly clean bore using singly-loaded ammunition with low bullet runout. In cartridges with more bullet runout, such as magazine fed rifle ammunition (where bullets get bumped out of alignment from slamming up the feed ramp), the accuracy of moly bullets is better. Walt Berger figured out why: At firing, the moly lubrication allows bullets to center themselves in the bore better than plain jacket bullets do. A Caveat: Moly bullets change barrel time by altering start pressure. You cannot simply drop them into a plain bullet accuracy load and expect good results. You will have to work the load up to best accuracy with the moly bullet. This usually means adding about 1% more powder. The loss of start pressure typically reduces rifle muzzle velocity about 50 fps when using the original powder charge, while adding the barrel time compensating powder will return it to pre-coated velocity. Peak chamber pressure will actually still be very slightly lower than the original plain bullet load under this circumstance.

Dr. Ken Oehler was involved in some measurements published in Precision Shooting magazine that showed moly plated bullets appeared to have slightly higher ballistic coefficients than plain bullets. This was a velocity loss between one screen at 120 yards and another at 1000 yards. The better B.C. causes a slight improvement in long range accuracy through a corresponding reduction in wind drift. This, again, is due to the improved bullet alignment in the bore Walt Berger reported. When a bullet exits a muzzle with any degree of tilt (and we are talking fractions of a degree, here) the nose of the bullet undergoes a coning motion, describing a slight helix through the air that reduces with distance if the spin rate is fast enough. The NRA book, Handloading, reported experiments done firing 826 rounds of M72 match ammunition after first segregating them by runout in the loaded cartridge. The 172 grain FMJ match bullet was found to group about a quarter MOA larger for each .001” of runout in the loaded cartridge, up to about .004” of runout, above which further tilt was self-corrected by the bullet aligning in the bore. Based on Berger’s observations, all the above numbers would have been reduced if the bullets had been moly coated because of better self-aligning in the bore. The resulting lower coning motion just out of the muzzle reduces drag during the first part of the bullet’s flight and before it settles. Keep in mind the coning is a mater of a circle just a few thousandths of an inch in diameter, but it doesn’t take a lot to increase drag at bullet velocities.

If you are just beginning to get involved in serious reloading, I would try to perfect plain bullet loading first, then start working with moly. It adds the above mentioned cleaning concerns and may mask bullet alignment problems you should address with your tools and technique. I would keep those variables isolated by leaving the moly experiments for later on, when you have something to compare it to.

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"First contemplation of the problems of Interior Ballistics gives the impression that they should yield rather easily to relatively simple methods of analysis. Further study shows the subject to be of almost unbelievable complexity." Homer Powley

A very thorough explaniation to your inquiry.

Let me add that home coating tends to eventually have most of the reloading equipment covered with the stuff and it is difficult to remove. I always wore latex gloves when handling the coated bullets and still ended up looking like a coal mine worker.

When it's time to clean the bore, you've got quite a job on your hands. Folks talk about Kroil cutting the moly from the bore, but the only thing I've found effective is Bore Tech Moly Magic, plus lots of elbow grease and bronze bristle brushes. Prior to using moly coated bullets the bore MUST be pristine clean of any traces of copper, or you'll get a layering effect that's really a mess to clean.

There is a velocity loss due to less bullet friction, so previous loads have to be worked back up incremently to achieve the same velocity and accuracy levels.

All said and done, the excess moly I have on hand is used for things that get squeaky and I don't mind the lube mess left behind. All bores have been scrubbed back to bare metal and only jacketed or cast bullets are pushed down them. My .02, anyway!

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"Firearms only have two enemies - rust and politicans" author unknown

I tried a few boxes of Sierra Moly coated bullets. I, personally, saw no improvement in the accuracy of either of the guns I tried them in. I know there are some that claim much improved accuracy, and it may really be true. It just didn't work any better in my guns than naked bullets.

If you plan to coat your own bullets, use a 500ml poly bottle for the moly and bullets. I've coated many this way with no trouble at all. You do not need any steel shot as the tumbling action inside the bottle will burnish the moly into the metal surface. I used the method recommened by Dow Corning one of the major suppliers of moly powder. My info go's back to 1991 product sheet by Dow Corning. The people at Neco have read the same sheet.

You can tumble two bottle's of bullets and come out with perfectly coated bullets in about a hour. The 500ml size will fit sideways in the tumbler and not create a mess. Just strain out the excess moly (you don't use much). Give them a light tumble in ground corn cobs to take off the dust, your ready to go.
Also you can get Dow Corning moly powder from any industrial supply house that handles machine tools.

As for removal Dow recommends Oakite Stripper R-6 or Wyandotte 11 Cleaner. Both are high alkline chemicals, just like garage floor cleaner. They are water base, use with care, when clean flush with clean water and apply oil or rust protection. TF

Did you work up the load separately? Were you running long strings between cleanings? Were you magazine feeding? Did you do any long range (beyond 300 yards) shooting with them? Just trying to get an apples-to-apples comparison. As I tried to say before, single-loading low runout cartridges in a frequently cleaned barrel at ranges of 300 yards or less, isn’t going to take any real advantage of the coating, IMHE. But I sure would be interested to hear what you tried?

Back a few years ago, Sierra's Kevin Thomas integrated some moly-coated bullet experiments into their normal QA testing. Like you, he saw no improvement, and actually found that statistically, they were slightly less accurate than the plain bullets they were based on. But, he also seemed (from the limit of details in his article on the experiment in Precision Shooting) to have done nothing but substitute the moly-coated bullets into their standard test load. The test guns were all single-loaded Remington actions in machine rests, and the barrels were cleaned at the usual regular intervals. In other words, basically, he skipped everything needed to see any improved performance or even to find the basic accuracy of the coated bullets. The exception was his testing of Norma's claim of extended barrel life, which neither Kevin nor anyone else I know takes too seriously. Bore wear is not usually the cause of barrel failure, and moly does nothing to cut down on throat temperature exposure, considered by most to be the main culprit. Norma has a 100 round 300 meter target posted on their sight, fired from a 6.5x55 with 10,000 rounds of coated bullets through it. It is pretty impressive, but I’m not sure what one gun’s performance really proves? Nor do their load details appear. It could be a reduced pressure and temperature load?


jaguarxk120,

No corncob buffing step? No wax coat? I'm not knocking your process. May be fine; as I said I just can't vouch for anything but the NECO process I am familiar with. The big problem I've seen in most testing of moly-coating is lack of apples-to-apples controls. People change processes and test conditions, assuming it makes no difference, but don't do any controlled side-by-side testing to prove that. A lot of people who have found moly coating to be worthless have based that assessment on either coating by methods other than the NECO process or, as I described above, have been single-loading low runout cartridges in frequently cleaned barrels, and are shooting at ranges too short for the small BC improvement to be seen on the target.

Thanks for the cleaning information. I have long used the mild abrasive bore cleaners, like Remington 40X or Iosso Bore Cleaner, and these also remove moly with the exception of the neck corner build-up I described. I’ll give the alkaline water-base material a try on that problem area in a bolt gun. Most of the moly-coated bullets I shoot are through gas guns, though, and I don’t want to get water-based degreaser in them if I am not doing a full disassembly. Getting it trapped in between the gas cylinder and barrel on a Garand, for example, is asking for corrosion. The Gunzilla product avoids that problem.

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"First contemplation of the problems of Interior Ballistics gives the impression that they should yield rather easily to relatively simple methods of analysis. Further study shows the subject to be of almost unbelievable complexity." Homer Powley

I didn't go to extrodinary methods in my shooting. I started out simply replacing the Moly bullets in some of my proven loads that shot near 1/2 inch groups. I saw no improvement, but then too, I didn't see any shooting considerably less. I did try a few loadings and powders til I ran out of bullets to play with. I am not in any way knocking the Moly bullets, I just saw no improvement in my 2 guns. Whenever I am testing loads I single load them as opposed to using the magazine. The longest shot I can make at the range is right at 250 yards so I wasn't able to test them beyond 300 yards. Again, I am not knocking the moly bullets or those that swear by them. I just get as good or better accuracy with plain old copper bullets and I don't have to go through a couple of different solvents to clean up the copper fouling/Moly fouling. If someone has good luck with them, you certainly don't need my permission or approval to continue with them. If I had seen any real, measurable improvement at my 250 yards, I would most likely still be using Moly. My experience is certainly not labratory type investigation, but, I cannot justify the extra cleaning and cost for a bullet that does not give me something measurable even if it is only 1/8" 250 yards.

Testing?? I guess you could say we tested them. A few thousand shots at PD's in South Datoka. They, the dogs, blew up as usual but the cleanings were less. Did not take as long to clean once the barrel coated. Used a bronse brush with alochol to get the carbon out, then Shooters Choice on nylon brush or mop to remove any copper. We ran four gun battery's so we were always shooting from cool barrels. Shots taken from 125 to 500 yds. A good solid hit would make the dog vaporize. My partner would sometimes get a double triple depending how close they were together. But our shooting was consistant rotating guns cleaning after 20-30 rnd. and spotting for the other guy. TF

Great Thread! When I first opened up Dixie Slugs, I bought all the equipment to moly coat our hard cast heat treated slug/bullets that were to be used in rifled barrels. This setup uses the Lyman Vibrater, a seperate pair of bowls (one for the moly and one for the corncob cleanup), ceramic tumbler media, and Lyman Super Moly. We had tested MsMoly spray and did not like it. As the folks said....it's messy! We never had any build up, etc. What we did find in testing various bullets.......is the soft pure lead Foster slugs, infamous for leading, shot clean with run through the moly system. We shipped all our ammo for awhile moly coated and never had any complaints! Later we switched to a thin Alox wash that was must faster to apply (and cleaner) and still continue to use Alox today.
I still think there may be some application for moly on cast
bullets???????
Regards, James

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We've discussed moly coating of cast bullets with Marshall Stanton and he's still not too up on it. He thinks, like Mr. Gates, that a good lubricant is best for cast bullets.

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"Firearms only have two enemies - rust and politicans" author unknown

I too, bought the Lyman moly kit and found it produces beautiful results. My plan is to use polygonal rifled barrels and moly coated bullets, a-la David Tubb. When shooting varmint it's a pain to have to stop and clean after every 50 to 100 or so shots. Now however, I discover that Tubb has switched to Boron Nitride as the coating of choice. Its cleaner, leaves a clear coating on the bullet, is slicker and doesn't build up in the bore. I received the following from Superior Shooting Systems when I asked about the new technology:

"To begin, moly coating will still be available. As for the boron nitride, we will be offering a new bullet 117gr green tipped both bare and BN also the boron coating will be available to the public.Terms will be minimum of 1000 bullets @.05 cents each you pay shipping both ways and if you want to mix say 500 224/80gr with 308/168gr then you also get to sort. Not recommended that you send 224/69 gr with .224/80 gr.
Have fun
Brenda"

Tubb has reportedly gone 600 rounds between cleaning, but he uses Schneider polygonal barrels.

Now we have something else to play with!

Interesting post, Axlenut - let's hope there will be followup on the process. Think all of us would be in favor of more shots between cleaning.

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"Firearms only have two enemies - rust and politicans" author unknown

We used boron nitride on forge dies and billets in an isothermal forging process. If my memory is correct (which it seldom is anymore) these were 8,000 ton presses and the nickel alloy forgings weighed 200-300 pounds. If a part got stuck in the dies it could cost a 100k in time and lost production getting it out. If the dies were destroyed that was a million dollars down the drain.

Don't mean it will work on bullets, I just thought I would share.

Well guys, I'm a sucker for experimenting with anything new, and if someone said coating bullets with Shake and Bake reduces group size, I'd buy a case. I still don't know which type of BN they use, I found references to cubical and another that seemed to be a powder that results in a hexagonal lattice structure. Apparently BN is used in cosmetics, so it's not toxic. Then there is no mention of how it's applied, I assume by impact plating like moly, but i don't know. Whoever gets this stuff on the market for us DIY types will score a few bucks, if the process is suitable for home application. Tubb did mention that BN costs 10 times more than moly. I've got a new Cooper Phoenix on order, and I'm waiting for a blueprinted Remington 700 to be finished, so I'll send off a thousand bullets for one of them and compare BN with moly.

I have guns that will shoot non moly bullets at 4200 fps. But I don't do it, because it burns out the barrel throats and gets Copper fouling.

I can shoot much faster, but I limit my moly bullets/barrels to 3600 fps

I limit my non moly copper jacketed bullets barrels to 2600 fps.

I limit my hard cast bullets to 1600 fps.

Sounds like a perfect plan to me, tnekkc!

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"Firearms only have two enemies - rust and politicans" author unknown