Barrel break in and moly coated bullets?

[DenisA]

G'day die hard moly users who also like to break in barrels................ ..................... 2 controversial topics in one. I could have thrown cleaning carbon in there but I thought that might have finished Keith off.

I've started shooting moly'd bullets in a couple of barrels and have seen some great benefits that will keep me mollying. I'll be starting a new barrel soon and I subscribe to the idea of breaking barrels in. Not strictly following a process, but just enough that the individual barrels stops copper fouling. It make sense to me that I should break in the barrel with naked bullets, but I thought I'd ask the questions and see if I could start an argument.

I should clarify that I don't think there would be any advantage to breaking in a barrel with moly bullets, but all the bullets I currently have for the next barrel are moly coated and I think that may possibly be a negative to the break in process.

What's the consensus, to break in naked or not?

[scott/r]

Hang on, let me get a drink. This should be interesting.

[saum2]

I'm not the expert but, 2 barrels I've run-in with moly & HBN projectiles have been hummer barrels. Either they were good barrels anyway I don't know. Another barrel (7mm) was/is a hummer i used naked bullets.
Another shooter said to me some time ago that I should run in the barrel with naked and then switch to moly coated. Does it make a difference I don't know, both ways worked for me.
Your call.
Geoff

[Razer]

I will stick my neck out here.
Breaking in a barrel is equivalent to lead slugging the rough spots and machine marks out.
As long as you are running the equivalent down the barrel I would assume that it would make no difference, except, copper is usually the gauge as to whether the barrel is being run in properly/sufficiently so moly may indicate that the barrel is run in before it actually is?
The rough spots would still take the moly off the projectiles down to the copper so may make no difference, but, I, personally would use naked projectiles.
I will now retire to my foxhole ready to receive incoming shells.

[johnk]

Don't have anything that's not molied, so that's what I use - always leftovers, wherever possible the ones with the longest bearing surface.

Running in is about the same as a flu shot every year. I know I need to do it, but it never gets me excited.

[shooter mcreid]

Forgive me if this is a silly question but does moly add to the diameter? Typically how thick is the coating? I have never done it, but wondered.

[DenisA]

I will stick my neck out here.
Breaking in a barrel is equivalent to lead slugging the rough spots and machine marks out.
As long as you are running the equivalent down the barrel I would assume that it would make no difference, except, copper is usually the gauge as to whether the barrel is being run in properly/sufficiently so moly may indicate that the barrel is run in before it actually is?
The rough spots would still take the moly off the projectiles down to the copper so may make no difference, but, I, personally would use naked projectiles.
I will now retire to my foxhole ready to receive incoming shells.

Exactly my thoughts but I wasn't sure if the moly would fill the troughs and reduce the effective lapping of the peaks......... Kinda thing.

[KHGS]

As a looooong time moly user, I run in with moly. The barrels we use are all match grade & require very little running in anyway. There that was easy wasn't it?
Keith H.

[DenisA]

Forgive me if this is a silly question but does moly add to the diameter? Typically how thick is the coating? I have never done it, but wondered.

No measurable difference using my equipment which is only accurate to a tenth of a thou.

[DenisA]

As a looooong time moly user, I run in with moly. The barrels we use are all match grade & require very little running in anyway. There that was easy wasn't it?
Keith H.

Very easy. Good enough for me. Thank you Keith and everyone else.

[Tim L]

Why are you using moly when Tungsten disulphide is so much more suitable?



Comparison between Molybdenum Disulfide (MoS2) & Tungsten Disulfide (WS2)
Tungsten Disulfide (WS2) is one of the most lubricous materials known to science. With Coefficient of Friction at 0.03, it offers excellent dry lubricity unmatched to any other substance. It can also be used in high temperature and high pressure applications. It offers temperature resistance from -450o F (-270o C) to 1200o F (650o C) in normal atmosphere and from -305o F (-188o C) to 2400o F (1316o C) in Vacuum. Load bearing property of coated film is extremely high at 300,000 psi.

Tungsten Disulfide (WS2) can be used instead of Molybdenum Disulfide (MoS2) and Graphite in almost all applications, and even more. Molybdenum and Tungsten are from same chemical family. Tungsten is heavier and more stable. Molybdenum Disulfide (Also known as Moly Disulfide) till now has been extremely popular due to cheaper price, easier availability and strong and innovative marketing. Tungsten Disulfide is not new chemical and has been around as long as Moly, and is used extensively by NASA, military, aerospace and automotive industry.

Till few years ago, price was Tungsten Disulfide was almost 10 times that of Molybdenum Disulfide. But since then price of Molybdenum Disulfide has doubled every six months. Now the prices of both chemicals are within comparable range. Now, it makes more economic sense to use superior dry lubricant (Tungsten Disulfide) and improve the quality and competitiveness of final product.

Tungsten Disulfide offers excellent lubrication under extreme conditions of Load, Vacuum and Temperature. The properties below show that Tungsten Disulfide offers excellent thermal stability and oxidation resistance at higher temperatures. WS2 has thermal stability advantage of 93oC (200oF) over MoS2. Coefficient of Friction of WS2 actually reduces at higher loads.

[Razer]

Posed that question on the forum before Tim, and with all detail and where to get it, but no response.
I bought my WS2 from the manufacturers in Canada a few years ago and am still growing the arm and leg back that it cost me at the time.
It does go along way and does a beautiful job and doesn't come off on your fingers when handled.
I pulled a few WS2 coated projectiles 2 days ago and they had been sitting in the safe for about 3 years and were still evenly coated even after the bullet puller had grabbed them and dragged them out of the case.
I used the ball bearings in the jar with the projectiles and WS2, then placed in tumbler(in the media)and left them for two hours. Polished them using a length of cotton sheet(couldn't get any more pantyhose!!) Does a good job if the projectiles are given a good wash in Shellite and then left to dry before coating.

[Tim L]

I've been using it for the past year Razer, from Canada also.

I apply wet and like you say it sticks better, but that's one of the advantages, it want's to stick, particularly to stainless steel (which is good, cos that's where I want it to stick too )whereas moly and HbN don't.

I don't know what moly does, clearly it does something but I doubt it's lubricate. More likely just a boundary layer like the Egyptians using sand to move their stone, 2000 years later we can still see the damage!

[AlanF]

My 100gm of moly is about run out (after doing about 25,000 bullets ). So where can I get WS2?

[Barry Davies]

A question that keeps bugging me.
If these coatings are temp resistant up to 650 C how do they perform their design function in a chamber which reaches temps much higher than that?
Would not their properties be destroyed almost instantaneously?
Anybody have any knowledge on this?