I have been told that the folks at Powell River Laboratories, Oakridge Tennessee have stopped using moly. The "rumor" is that the molybdenum sulfide coating the barrel is hygrostatic or absorbs moisture. The sulfide plus water reacts to form sulfuric acid. This is not good for barrels.

Moly does have some advantage, mainly in reducing fouling. That is all I value it for.

Should the moly be scrubbed out of barrels to prevent acid erosion of the bore?

Should moly be avoided altogether? Or is this hogwash? I know those GS Custom bullets sure are sexy in their gray-black coats. Horrors! Moly bad for bores???

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RAB

Hi RAB,
It depends on the grade of moly that is used. Low grade (cheap) product contains impurities that could attract and hold moisture and react with some of the impurities. The container we get our moly in is left open and with Port Elizabeth right on the coast, and the rain season just about done, the powder is still exactly the way it was when we got it last year sometime.

When we first heard of this rumour, I discussed it with the chemist we consult with and he said that highly refined moly is chemically inert and suggested that we run a test. We dedicated one of our 220 Swift rifles and, apart from running a dry nylon brush through the bore after shooting, we have not cleaned this rifle since January. It has been to the range for experimental work numerous times and out hunting four times. After more than 300 shots it is not grouping the way it could, but no rust. We have been shooting moly coated 40gr HV bullets in it at 4400 fps since the beginning of 1998.

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Gerard Schultz
GS Custom Bullets

R.A.

After reading so much conflicting information on moly coated bullets I emailed Hart for their opinion.

Their response: "We do not recommend the use of moly coated bullets in our barrels as we have found no good way to remove the moly without damaging the bore."

The logic of the statement from Hart escapes me. The purpose of shooting moly coated bullets is to put down a coat of moly in the bore. Why would one want to remove all of it again?

That is like having a vehicle sprayed with rustproofing and then complaining that the car wash shampoo you are using won't remove all the rustproofing or using an anti-static cleaner on your computer screen and then complaining that the dustcloth can't get the anti static off the screen.

In any case, we found that after normal cleaning of copper and nitro fouling, any moly coating remaining in the bore cannot even be measured. If you cut a section of barrel that has been shot extensively with moly and cleaned normally, you can't even see the stuff unless you use a microscope.

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Gerard Schultz
GS Custom Bullets

: )

First you want it in, then you want it out. You are makeing a job out of nothing!!! The moly-sulfuric acid thing is bunk. Forget you ever heard it. Shoot moly bullets, don't shoot moly, do what makes you happy and seems to work best. It won't damage your bore. Agresive cleaning sure will. If moly saves you on rod strokes that is good enough for me. I shoot moly in all my rifle cartridges that use jacketed bullets. Does it make a huge difference??? No. I do however, nottice that it cleans up faster. That is all I need. The fewer times I poke a rod down the muzzle of a $500 Garand barrel the better. For what is it is worth I do use the moly prep grease at the same time. I leave the bore treated after I clean it and before I put the preservative (LPS-3) in as a last step. I have never had any rust in any bore so treated.

Bores still foul when using coated bullets, it just takes more shots to foul them to the degree that accuracy is effected. The "accepted cleaning practice" has been to use JB or some other type of abrasive cleaner. I assume Hart's statement is based on the use of an abrasive in their barrels.

One of the most knowledgeable "gun" writers that I know is M.L. "Mic" McPherson and Mic uses moly-coated bullets and that's good enough for me. I don't know if there needed for big-game hunting bullets but it can't hurt and the evidence I've seen strongly indicates it is very beneficial for high-volume shooting (prarie dogs, etc). Barrel makers are very conservative about their barrels....one says "OK" to flute and another other says "no way" or you'll void the warranty (what warranty?)...some won't sell a small coutour SS barrel and others say "why not?"

If Moly was corrosive and dangerous to a steel barrel in any way, shape, or form, just imagine what it would do to copper(bullet jackets). I have yet to see a moly coated bullet turn green. Think about it. MM

Right! I will sleep well now. I am sure you will get some BS from the barrel makers. I like the moly. I am glad to hear about the minimal coating effect in the barrel, which I always thought was insignificant anyway. I will shoot the GS Custom with abandon, but I will not bother with coating any bullets myself. Best left to the professionals, like GSC!

Gerard,
Now that I have your attention:
For Pete's sake did you ship the the .475 FN and HV bullets? I know, it has only been eight weeks and the terrorist horrors could be fouling up the mail. I picked a great time to try the regular post instead of air mail, eh?

Also, Gerard, could you possibly ever bring yourself to produce an HV and FN of 300 grains in the .375 caliber...and coat them heavily with the finest of moly? I will develop data for them for Saeed to post in the reloading pages, with the 375 RUM. PUHLEEZE!!!

I am expecting some one-hole groups.

I am trying to make my next assignment four days per week and close to home so I can do that reloading and shooting I have been dreaming about.

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RAB

Gerard __

Another "myth" I've heard or read is that molybdenum disulfide breaks down into molybdenum and free sulfur at the combustion (and friction generated) temperatures common to firearms. And we all know that sulfur is hazardous to the health of cartridge brass.

Again, bunk! Molybdenum disulfide melts at around 4700F and dissociates at about three time that temperature. Can't happen!

Feel at ease in that respect.

Good shooting.

Robert

Here is link to a article on moly. http://www.precisionshooting.com/aug98.html

Hi RAB,
I had a whole bunch of e-mail this week of parcels arriving. Seems like a plug was pulled somewhere. If you don't have yours by Monday or so, drop me an e-mail and I will do the neccessary. If you consider the design of the HV range, you must bear in mind that a 300 grain HV is going to be about the length of a jacketed lead round nose flat base bullet of about 370 grains. Such a bullet will need a one in thirteen or tighter twist to stabilise and that means that, from some 375s, they will keyhole regardless of distance. Even if the rifle is one in thirteen or twelve, a bullet of that length will always be more prone to failure than a shorter one. See the picture at http://www.zibycom.com/members/002245268/Site2/375380gr.html for a prototype 380 grain 375 bullet (not one of mine) and what happens to them in wetpack. In buff and ele things will probably get worse especially if they are driven hard. An FN at 300 grains could work in the right twist barrel but would need 378 Weatherby case capacity to out-perform the 270 gr FN. You may sense a bit of reluctance on my part to go down the "long and heavy" (and slow) route

Robert,
Thanks for the info, I did not know the temperatures could go that high. We used to offer coated as well as uncoated bullets while I tried to make up my mind about moly. Once all the facts were in, it was a simple choice and we now offer uncoated bullets only as a special order item.

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Gerard Schultz
GS Custom Bullets

Here is a link to one of the best, no BS articles on Moly I've ever seen:

http://www.jarheadtop.com/books.html#

scroll down to the book: "Care Cleaning and Sportsmanship" and click on the link to sample chapter 4. Its a great review of how moly works, what it is, and its positives and negatives including electron microscope images of moly particles.

I will tell you that moly has extended the serviceable life of my match barrels from around 3800 rounds to around 6,000 rounds in my .308.

Gerard,
I think what the good doctor is looking for is a looooong range HV bullet for a .375 rifle. There are not many choices out there for those who like to shoot big bores at long ranges. I bet one would work great in a State Arms Mach V rifle (.50 BMG necked down to .375).

RAB,
I may be mistaken, if I am, please correct me. Also, be sure to let me know how the 705gr semi-boreriders shoot in your JAB when you get a chance to shoot them.

Gerard,
Thanks for the response. So you are going to make me use 300 grain Barnes X-Bullets instead of the GSC product? I agree that too long in the shank is a bent bullet waiting to happen, but the darn X-Bullet is a monometal copper bullet that works superbly. I am drawing the line at 300 grains. I know that a 300 grainer of any make can out do a 350 grainer of similar make in penetration. 300 grains is all I am asking for. It is such a universal weight for the .375 bore.

Of course I will put the lighter 265 grain HV and 270 grain FN to good use, even though they do look stubby, but how come Barnes can do it and you can't? It escapes me. Has adequate testing been done?

I would use the 300 grainers in 375 RUM and 378 Wby rifles at 2700 to 3000 fps. I am sure your bullets will do it.

That is light and fast not heavy and slow in my view.

BMG,
You are right about long range use I have in mind. I am trying to line up some easier work so I will have more time to shoot...those 705 grainers in the 510 JAB.

I put in a 14 hour day today, including hospital rounds on 18 patients, family conference...ICU, CCU, admissions from the ER, and Mr. and Mrs. John Doe can't accept that Mom has ALS and can't get off the ventilator...it has been hell. "Too Long Have I Hunted the Mammoth ... Today!" I have to start over again in about six hours and do it for three more days straight before this session of hell is over. Get the drift?
Best Regards,
RAB

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RAB

RAB,
If you thought stooping to blackmail will work to get you a 300 grain 375, you were right I will do some external ballistics with a 300 gr HV in the first half of November and see how they go. What is the case capacity in water of your 375? I have a 375H&H and it does not do well with monometal bullets over 270gr but a bigger case fares better as we have seen with the 378s.

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Gerard Schultz
GS Custom Bullets

BMG: How accurate is this MACH V rifle ?
Gerard: It is simply necked down .50BMG . . . I think 300gr bullet at 3750 fps or so . . .

Gerard,
What a good guy you are! I will be shooting them in the 375 WBY, 375 RUM, and 378 WBY.
I would guess that the case capacities of these would be roughly 95, 105, and 115 grains of water respectively. I will do my best to look up the precise answer or weigh the water myself.

I bet even Saeed would be interested in an HV and FN combo of 300 grain .375 bullets. After all, they already come coated with the finest moly and he won't have to waste the time of coating X-Bullets himself.

What a great guy! Thanks again.

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RAB

RAB,
I feel the pain. My motto is 'Make hay while the sun shines' and recently I've needed sunglasses & SPF 45 ;-) I hope you have time to visit your family soon, you know, the .510's - .458's - .416's - .375's - etc.

Jiri,
My friend has one and the thing is extremely accurate. Klaus (the guy in WI that makes them) has had some HV solids over 5000fps hence the name of Mach V.

[This message has been edited by BMG (edited 10-29-2001).]

RAB, Thats ok, don't hassle with the water capacity, we have the 375s you have on record. I thought you might have something interesting like that necked down 50 that was mentioned. As a matter of interest, we had a 30-06 on the range last week and ran a 1.38" long spitser boattail at 3950 fps. We are going to have some fun with this one.

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Gerard Schultz
GS Custom Bullets

Gerard,
Nothing that "interesting," as the 375 Mach V, for me, thank you. I am a very dull guy, some even say I am a "big bore." That sounds like an incredible 30-06 load. Now that is interesting! Can you divulge more?

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RAB

[This message has been edited by R. A. Berry (edited 10-30-2001).]

There is a fair bit of work to do still, the target speed in a 308 Win is 4100 fps and with a BC of 0.590, the 10mph wind drift at 1000 metres is 21". This seems like a good thing. It will be interesting to see if we can make it workable and useful for some application. I must admit to a holler and a whoop when we fired the first two from the 30-06 and the Oehler read 3949 average. Recoil was about like a 223.

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Gerard Schultz
GS Custom Bullets