Moly coating?

[Mnguy56]

New to the metallic reloading. Can anyone give me some insight into doing your own "moly coating"? Appears to be just a "powder" on the bullet that really does not adhere, or.....?
Friend of mine does it in the vibratory case cleaner. Moly and bullets in a small jar that he lets bounce around for about 92 minutes.
What all benefits are derived? Less coppering of the bore? Better accuracy?
Any comments most welcome and thanks for taking the time to respond!

[Gabriel's Hobo]

I use factory moly'ed bullets exclusively in my High Power service rifle ( Bushy DCM Rifle). The main reason I use them is for the easier cleanup. I also go longer between barrel cleanings with them due to the lessened fouling. I have not tried coating my own so can't help there. You may find that you need to increase your case neck tension to hold them more securely. I'm using a RCBS full length sizer and no crimp for over 4000 rounds and have had no problems, but YMMV. On case neck tension, going over approx. .004" will not help, because the elasticity of the brass will be exceeded. In other words, the bullet will become a very poor expander button and will not be held one bit tighter.

[30Cal]

I shot them for about a year and a half. I found the "benefits" didn't amount to much at all. I did find that it promoted pitting.

[castnblast]

Moly coating is a salt so to speak. It will increase barrel wear. I generally avoid moly bullets. my $.02 worth..

[mc223]

Moly has been beat up and praised for years.
I have been coating my bullets for nearly as long as moly has been out there, and have no corrosion or pitting or any other Ill effect. I do not believe it is like "salt" and I do not believe it causes wear to a barrel.
I coat my bullets in a Thumlers Tumbler(Rock polisher) I put a teaspoon of moly powder in the tumbler barrel with a couple hundred bullets and a couple hundred regular "BBs". Tumble for a couple hours, seperate the bullets and BBs from the moly in a kitchen flour seive, polish in an old towel and seperate the BBs from the bullets with a magnet.
The moly will be well bonded to the bullets. Called impact plating.
In a direct comparison of the same bullet type and weight and the same powder and charge weight. A moly coated bullet's velocity will be lower due to less resistance both in entering the barrel and traveling down the barrel. Powder charge would then need to be increased to obtain the same velocity as was acheived by a "naked" bullet.
I have not seen an increase in accuracy using a moly coated bullet. I can shoot more between cleanings. Accuracy does not seem to fall off due to fouling as soon as it would with non moly projectiles.
If you choose to us moly you will need to pretty much commit to using the stuff. You can not shoot a few moly bullets then a few non moly bullets and expect good performance from either.
There is a ton of info on moly and other coatings in cyberland. Do some seaching and make your own decision whether moly is right for you and your intended use.

[Unclenick]

There are several benefits to the moly process, and a couple of warnings to be careful how you go about it. Most of the complaints about the process, such as the pitting and rust promotion cited above come from employing moly that is of low refinement and has free sulfur in it in enough quantity to react with moisture to form sulfurous (SO3) acid radicals that promote corrosion, or which has been recycled from metal stamping operations and actually contains small amounts of free iron that easily rust and seed rust in adjacent steel by oxygen exchange. Inexpensive moly comes from that source.

This is one process where trying to save cost simply doesn't pay.

Sierra and Berger and Norma all license the original process patented by NECO. This method uses a laboratory grade pure moly and drives it against the jacket surface with steel shot in a process called impact plating, as MC223 said. This improves the adhesion of the moly to the bullet. In a recent piece in Precision Shooting, the process's co-inventor, Merrill Martin pointed out that much of the moly on poorly coated bullets gets blown off the bullet as the case neck expands to release it and before it moves forward to the throat, thus negating much of the coating's advantage. So, it is not surprising that people who got the non-patent process kits and had the rust trouble also didn’t see much benefit.

The NECO process also overcoats the moly in carnauba wax to make it less dirty to handle and to discourage moisture. I don't see corrosion or verde gris on bullets coated by this process despite some having been in my less-than-bone-dry basement for many years now. If acid radicals were forming, the copper would have revealed it faster than steel. Sierra, Berger, and Norma would not be using this process if it caused corrosion of their stock or of their customer’s guns.

Like Gabriel's Hobo, I shoot moly in competition and have for years. It allowed my old DCM Garand's barrel to shoot 100 rounds without cleaning or losing accuracy, where it had always fouled badly and lost accuracy after about 30 rounds before I tried moly. I later found firelapping it helped even more, but that's another whole story.

I've never seen any trace of corrosion or pitting resulting from using moly bullets, but then I have always use bullets coated by the NECO process. Sorry if that sounds like a commercial, but I've been through this discussion many times and always found people with moly problems used some inferior kit or process that cost less because it skirted the NECO patent by skipping something important. Merrill Martin describes having put a lot of experimental work into arriving at a process that produced something that really worked. It is wishful thinking to believe that his work can just be blown off for something simpler. He even mentioned the complaints about moly in his recent piece and figured they were all true for somebody somewhere who had used an inferior approach.

Back to benefits: In 1960 or ‘62 (I’d have to look it up), the NRA published an experiment by shooters using M72 ammunition in match accurized M1 Garands. The experimenters fired over 800 rounds after carefully measuring the runout of the bullets as they were seated in the cases. They found that for every thousandth of additional runout, groups opened up another half m.o.a. on the targets, until they got to four thousandths of runout. Beyond that, they saw no additional deterioration of group size.

Examination of the rifling marks on recovered bullets shows that up to a point (four thousandths, for the 172 grain LC .30 caliber match bullet), a bullet maintains the tipped attitude in the bore that it starts from the case with. On recovered bullets, you can see the rifling on the gradual slope of the ogive doesn't start at the same distance from the base all the way around a bullet that was tipped. Beyond a maximum tipping value for a given bullet and bore, the bullet is being straightened enough by entering the bore that no additional runout matters.

The main benefit of proper moly coating, aside from cleaning, was studied both by Martin and later by Walt Berger in some detail. They found that the coating allows a tipped bullet to straighten when entering the throat much more easily because the lubrication lets it slide into bore alignment with less force. Recovered moly coated bullets always show uniform rifling engraving even if they had started out tipped. The result is, the small spiral path described by the nose of the bullet on launch due to axial misalignment is largely eliminated. That reduces not only group size, but also early flight air resistance giving a small apparent increase in ballistic coefficient to the moly coated bullets. This tipping realignment matters in self-loading guns in particular, because they tend to tip their bullets as the cartridge slams up the loading ramp, even if those bullets were seated straight to begin with.

You have to do two additional things to get best effect from moly coated bullets:

1.) Remember the coating will reduce start pressure so your powder will have more trouble getting started burning. You will lose about 50 fps as a result. You will therefore need to work your sweet spot loads up over again to match or exceed your best pre-moly accuracy.

2.) Sharp case mouths resulting from a recent trimming and chamfering will scrape even the impact plated moly off a bullet. Run newly trimmed and chamfered cases over a carbide sizing ball in your sizing die or push them against a sharpened wood dowel spinning in a drill to burnish the sharp edges down before loading them.

[Slamfire]

Over the years at the Nationals, I have been squadded with some of the finest shooters in the world. There was a time when moly was the new thing, now it is fading away. Talking to these shooters, most have abandoned moly.

Why?

They have had negative results with the stuff. One Long Range Champ told me his average was lower with moly bullets. Another top ranked guy was positively vitriolic about his negative experiences. The number of people who have walked away from moly is starting to be greater than the number of people who use moly.

The barrel life claims, less cleaning, all that stuff have just not held up.

Moly, it just another thing that can go wrong. So why use it?

[cdoc42]

I started coating my own bullets exclusively with the NECO kit in 1995. Coated them with carnuba wax as well.

I never saw any increase in accuracy, although that was never really a strong claim. The major reason advocating its use was increased barrel life via longer times between cleanings.

I could never really tell if I was getting the rifle clean because the patches consistently came out black due to the moly. It was difficult to see copper as well, although presumably the moly prevented the copper adhesion.

I quit using moly and I de-moly'd all the bullets I had impacted when my 7mm STW went from sub-MOA to shooting all over the place, no matter what I did with it.

There were those who advocated only moly-coating the barrel, not the bullets, and that made sense to me. I began to believe that continual shooting moly-coated bullets left more and more moly in the barrel and contributed to the demise of accuracy in that 7STW.

I recognized that I could wash my hands with soap and water to remove any moly, so it had to be water miscible, if not soluble. So I spent one entire week, with nightly cleaning that 7STW with dish soap and water, powdered Borax, and eveything else I had on hand. After one week the patches were still black and my accuracy still was horrible. I didn't have a bore scope so I can't comment on what it looked like inside. But the rifle is worthless at this point.

[amamnn]

I've used moly and never had any problems. I never really saw a whole lot of benefit either. All my match barrels are hand lapped and I use good quality jacketed bullets, so I don't experience much in the way of copper fouling with or without moly. I started with the moly coated bullets and changed to using moly paste applied directly in the barrel which seemed to work a bit better in keeping the carbon build up down.

Since moving to WA from AZ, I have stopped using moly at all, having seen more than one barrel ruined in the high humidity environment here. I think using the paste gives you more control over how and how much moly is applied. Hoppes makes or at least used to make, when I was using it, a high grade moly paste. You should not have problems with black patches using paste since you burnish it onto the surface. I used to be able to shoot a single class complete match (25 rounds plus sighters) with one application. I would clean the gun thoroughly and then apply a bit of paste to be ready for the next match.

Whatever method you use, you must be sure to clean your barrel cleaner than most people usually do, especially the chamber area. all the shooters I have talked to who had problems with moly failed to clean their guns completely. I went for a little over a year here using the moly paste before I saw enough ruined barrels to convince me it was not worth the risk.

[Unclenick]

Slamfire,

I don’t know what moly methods the shooters with problems were using? That’s been a big part of the problem. Regarding accuracy and loads, my Garand 600 yard scores went from the low 180’s to the low 190’s on the NMC after switching to moly. This was my old DCM Garand, bedded and accurized except it was the original barrel. The clean gun shot 0.7 m.o.a. at 100 yards after fitting up, which is why I never changed to a match barrel, but fouling made groups fall apart during the slow fire stage. The moly prevented that.

Sierra ballistic technician Kevin Thomas ran tests of moly bullets by working them into their normal lot evaluation testing from machine rest actions. He saw a very slight accuracy loss (like a 20th of an MOA, IIRC) but didn’t adjust the loads, either. He also found no barrel life extension, getting the usual 3500 rounds, if memory serves. On the other hand, Norma has an impressive 300 meter 100 round 6.5x55 group on their web site fired from a barrel with 10,000 rounds through it. I would not have expected lubrication to extend barrel life because barrel wear is mostly throat heat stress cracking, not friction damage. I can only speculate that with some powders, reduced start pressure may mitigate the peak temperature the throat is exposed to, but this will be peculiar to some load combinations.

Based on Thomas’s accuracy experience, and knowing Sierra and the other manufacturers producing moly-coated bullets will not risk their reputations over the stuff, I have to think the people claiming accuracy problems have got some additional variable involved (see my example, below).


Cdoc42,

I can tell you how to get trace moly out of a barrel. I have a borescope, and can report one problem moly does cause with potential to deteriorate accuracy in some chamber geometries. This is a build-up of mixed carbon and moly that cakes in a ring at the step of the chamber neck where the neck narrows to freebore diameter. I expect you have some of this, and it is what you are seeing on patches. (I am also assuming here that you realize anything with abrasive qualities will blacken patches with fine steel particles (borax powder, J-B Bore Compound, Flitz, etcetera), and that you are sure you actually see moly and not steel coming out.) I used to employ a special tool I made to cut the carbon/moly ring out of my chambers, but because the moly gets mixed with carbon, I finally realized any cleaner that breaks carbon down will break the combination cake down, too. Slip 2000’s Carbon Killer should work fine. I used Gunzilla the last time I cleared some of this out. Left it wet overnight, after which normal cleaning took the ring right out. These product soften carbon cake substantially.

I am sorry your STW ran into so much trouble. It may, however, be a worst case application for moly coated bullets because of the slow powders used in those big cases. These powders are much less tolerant of reduced starting pressures than faster powders are. If you had an issue with this, you would likely have seen velocity extreme spread increase over plain bullet performance with the same powder due to the less solid ignition start.

The other problem the reduced start pressure could cause would result from there being more powder left unburned at the time the bullet exits the muzzle. Bruce Baer has reported accuracy loss in the large magnums due to muzzle funneling by burning powder particles. The hot particles from slow large magnum powders not only jet out of the muzzle at higher pressures than non-magnum chamberings produce, but gases and particulate matter still near the muzzle moments after firing get drawn partway back into the bore by the partial vacuum left behind when propellant gasses jet out. These particles are cooler and harder than they were as they exited, and are apparently abrasive enough to gradually help widen the last inch or so of the muzzle. That would get worse if reduced start pressure caused less complete combustion of the powder.

You could check for muzzle funneling it by slugging the muzzle from the breech end and seeing if the slug gets loose in last inch or so of the barrel? The cure is to cut the wide part off and re-crown the muzzle. Given that 7 mm STW barrels only have best accuracy for 750 – 1500 rounds anyway, if you are in need of setting the shoulder back and rechambering to recover the throat, you could get the muzzle trimming done at the same time.

[Trapper L]

Mnguy56, I have bought moly bullets and have bought the kits to do it myself. I don't fool with it anymore. The only advantage I've found is that you can shoot more between cleanings before accuracy falls off. But that creates a different issue. Like cdoc42, I had problems getting the crude out of the barrel. I finally got it out using a lanolin based hand cleaner to get the moly out and then soap and water to get the lanolin out. I didn't have any accuracy issues just I'm REAL picky about patches coming out just like they went in. It is a fact that moly will coat a barrel, that's how moly works. I'm not fond of having anything in my barrel- copper, moly, carbon, feral rats, cattle, etc. I quit using it and everybody that I shoot with has quit using it as well.

It may be that the larger caliber/catridges are having issues. My 30/338 Mag would be a large capacity case like the 7 STW. Maybe the smaller cases aren't having the issue. Uncle Nick, what are you shooting? Have you tried Danzac?

[Slamfire]

Regarding accuracy and loads, my Garand 600 yard scores went from the low 180’s to the low 190’s on the NMC after switching to moly. This was my old DCM Garand, bedded and accurized except it was the original barrel.

Shooting low 190's with an original issue 30-06 Barrel !!!! Wow! That is a rare barrel. You are going to miss it when you shoot it out.

It is also quite possible that you got better, the moly may have nothing to do with your scores improving. I have seen that with a number of shooters. They do something different on the reloading bench, and quess what, they shoot a good score next match, and attribute the reason to the new reloading technique. When in fact, they got better. The ammo stayed the same.

I don’t know what moly methods the shooters with problems were using? That’s been a big part of the problem.

I just ask questions like, "what cartridge are you shooting, what bullet do you use, what powder is in the case". Since I don't moly, I don't pay attention to the details of putting moly on bullets. It is more like, "You moly?". Yes or no is good enough for me.

I am certain that the people who I have talked to, are the type that pay attention to details. I am certain they decided it was not anything they were doing before they gave up on moly.

[Unclenick]

I'm shooting service rifles and a tac rifle with moly because of the alignment out-of-the-magazine factor. I use them in the Garand (the old barrel is on its last legs, alas), the M1A, and the AR. None of these are magnum hot cartridges. My Savage 10 FP also seems to like them just fine, and I have had good results on LR targets at 800 and 1000 yards with that rifle shooting moly-coated 175 grains SMK's.

The change in my Garand scores were directly attributable to fouling. Not only could I actually watch 600 hundred yard scores deteriorate through the SF phase, but when I got the rifle back to the hutch, I would run mop after mop after mop of Sweets through it and copper just never seemed to stop coming out. It took about 6 hours of 15 minute soaks before it finally was clean. The moly cut that way down and let the gun shoot. Where before the last 10 shots would be all 8's and 9's all around the clock, with moly they became 9's and 10's and X's, same as the first 10 rounds. Just my experience with that one rifle.

The M1A had a match barrel to start with (now completely shot out; have a new Krieger out by my lathe waiting for me to finish setting up my through-barrel lubricant pump). I never really did a plain vs. moly comparison in that rifle. Just shot moly. It worked fine and was cleaning slow fire targets regularly at our local league before the tell-tale irregular uncalled flyers started that signal barrel life conclusion. I found that gun very finnicky with the 168 grain SMK's, but it would should shoot tuned loads to about 0.8 m.o.a. I still like the old Garand better at 600 yards, but prefer the M1A for 200 yard awful-hand.

The AR has one of the last run of Blackstar Accumax electropolished barrels in it. Compass lake put it together for me and it drives moly-coated tacks. It's in the 1/2 M.O.A. neighborhood off the bench. It shot the hIgh score for the year at my club last year. (Work has kept me from shooting much at all this year.) No problems. Cleans up so fast I hardly feel I've done anything.

Working in engineering and science I see many examples of people confusing the causes of things. "Well, I flipped the red switch when the green light came on, same as always, but the widgets started coming out bad. Of course, my kettle started to whistle about then, too. And I had to turn the heat up in the shop until I got my coffee ready. And, I guess I didn't watch the warning lights too closely while I was making the coffee, but that shouldn't matter. I think it must be sound waves from the teakettle whistle getting in the control panel." You get my point. Independence of variables, including psychological ones, are easy to overlook, and people experience difficulty isolating them well. Cause and effect become murky. It would be fun to do some double-blind testing of shooters and ammunition.

[Bullet94]

I tend to believe David Tubb –

http://www.zediker.com/articles/mca.pdf

http://www.zediker.com/articles/mcc.pdf

http://www.zediker.com/articles/articles.html

http://www.zediker.com/tubb/tubbmain.html

[Slamfire]

David Tubb placed second this year at Camp Perry. It was good to see him out on the firing line as he has had serious knee problems. I think I saw his knees, and the surgery scars looked like little zipper marks.

Mr. Tubbs is an outstanding shooter, has won more Championships of any shooter that I know of. He has been a net positive force to Highpower as he is an experimenter, and has added products to the market that have turned out to be a good thing.

He has championed Moly, and because of his stature, that has added a lot of credence to the use of moly.

However there are a lot of very excellent shooters out there who don’t use moly. And from what I can tell, most tried moly and gave it up.

[Alleykat]

I've shot several thousand rounds of moly'd bullets through a bolt .223, bolt .243, and a .223 Bushmaster. I wouldn't ever, under any circumstances, run a moly bullet through any of them again.

The downside greatly outweighs the up, for me. Getting moly out of your barrel is a royal p.i.t.a. Moly does absorb moisture.

[Unclenick]

Again, whose moly was it and did you keep the barrel properly cleaned and oiled? The lab grade stuff has shown no sign of picking up water in my guns, but I don't leave the fired and dry afterward, either.

[W.E.G.]

I just had to have the NECO moly kit when it first hit the market.

I coated several thousand bullets, and had very good luck with them in service rifle competitions.

Problem is though, I didn't realize that the moly dust was escaping from the tumbler - and I thought I was taking solid precautions. A fine coating of moly powder got all over everything.
I moly-coated the TV set.
I moly-coated all the furniture in the rec-room.
I even moly-coated the kid.

SWMBO was NOT pleased.

So I gave up moly-coating.

[Unclenick]

First rule of hobbies of all kinds: they must be invisible to SWMBO.

[Gewehr98]

No problems, excellent accuracy, and my Krieger barrels love the stuff. I tumble the bullets in centrifuge cones with a pinch of the powder, throwing the cones in my big Lyman tumbler for about 30 minutes. I wipe them off, and use Meguiar's Car Wax as a finish coat.

I did it to minimize barrel temps and subsequent throat erosion from my 3200fps 6.5-06 wildcat, as well as reducing copper fouling. To that end, I'm quite pleased with the results. I will do the same when I finish my .220 Swift project soon.

I have to wonder about the source and quality of moly, the application techniques, and cleaning procedures when folks complain about barrel corrosion.

[Unclenick]

I think the street grade moly has been a big part of the problem and the cause of a lot of the bad experiences. There is always someone who wants to make a good thing on the cheap and winds up messing it up.

I'm surprised you are getting adequate results without steel shot impact plating. It would be interesting if you did some both ways and compared results to see if the improved adhesion doesn't help? A 6.5 may be a special case in that many of the bullets are so long they can get well onto the throat before the bearing surface clears the case neck and moly starts to experience significant gas blowby? What kind of barrel life are you getting?

[Walkalong]

Probably 75% or more of Benchresters tried them, including myself, and 99% of those who did gave them up, me included. A few still swear by them.

[Unclenick]

I'm not surprised benchresters would have little use for them. You guys are running match grade barrels that don't tend to foul badly. You clean frequently. You load ammo on equipment that produces essentially perfect bullet alignment to begin with. What's left for the moly to do? Unless you have one of the chamberings and powder/bullet combinations that see actual life extension, what would the point be?

Your point that some benchrest shooters still swear by moly bullets is significant. If these guys are succeeding in benchrest matches, they are regularly turning in groups below a quarter m.o.a.; so tight as to prove the complaints of lowered scores by service rifle match shooters are specious. If the service rifle shooter has a problem using them, some other issue with the load is involved, too. And that's very possible. Once you start altering start pressure, you are messing with barrel time and powder burn regularity. If you don't correct for that by adjusting the loads and/or choice of powder, you'll never get peak performance. Any change of a bullet or other reloading component requires reworking the load to check for peak performance sweet spots, anyway. That's just the way it is.