Barrel burnout

[Hugnot]

The tungsten sulfide, WS2, acts like a dry lubricant but when exposed to oxygen and water, acting as a catalyst, to form sulfuric acid, a stong oxididizing acid & tungsten oxides - like corrosion & rust & wet pre shot conditions. A steady diet of WS2 under warm & humid condtions would promote rusting & associated pitting in both 416R & 4140 steels. I don't plan to mess with WS2. I will continue to use the relatively benign 91% rubbing alcohol.

 

[Mikecr]

I've never seen a trace of rust on patches. Been using WS2 since the 70s (instead of moly).

A Comparison of Tungsten Disulfide and Molybdenum Disulfide

Tungsten Disulfide (WS2) and Molybdenum Disulfide (MoS2) are two of the most popular industrial dry film lubricants. Both are similar in many ways

ws2coating.com

 

[Hugnot]

My thinking is that both Tungsten Disulfide & Molybdenum Disulfide are sufides and being such are subject to decomposition where air (oxygen), water (moisture) and warmth (heat) are present. A product of sulfide decomposition would be sulfuric acid, corrosive stuff. The wikipedia explanation in regard to WS2 decomposition is sort to academic but gives some idea of the decomposition process. Granted, rifle barrel bores are sort of dark inside (no light of suitable wavelength) but the other elements like water (moisture) & heat are present. "Monolayer" means 1 molecule thick and it is likely that any WS2 coating would greatly exceed that. Long term exposures of WS2 to moisture & heat were not addressed. Looks like sunshine, humidity & warmth might make for WS2 liabilities on exposed chrome-moly steel surfaces.

I can't see any advantages of appling internal lubrication to rifle bores because any lubricant would be quickly worn off by hot powder burning gas & bullet friction. Chrome oxide would be formed on stainless steel barrel surfaces and that would act as a protective coating retarding rust, shown by rusty patches. Tiny micro size pitting might occur, not visible by bore scope magnification.

Tungsten disulfide - Wikipedia

en.wikipedia.org

"Although it has long been thought that WS2​ is relatively stable in ambient air, recent reports on the ambient air oxidation of monolayer WS2​ have found this to not be the case. In the monolayer form, WS2​ is converted rather rapidly (over the course of days in ambient light and atmosphere) to tungsten oxide via a photo-oxidation reaction involving visible wavelengths of light readily absorbed by monolayer WS2​ (< ~660 nm; > ~1.88 eV).[8]​ In addition to light of suitable wavelength, the reaction likely requires both oxygen and water to proceed, with the water thought to act as a catalyst for oxidation. The products of the reaction likely include various tungsten oxide species and sulfuric acid. The oxidation of other semiconductor transition metal dichalcogenides (S-TMDs) such as MoS2​, has similarly been observed to occur in ambient light and atmospheric conditions.[9]"​

 

[Mikecr]

I can't see any advantages of appling internal lubrication to rifle bores because any lubricant would be quickly worn off by hot powder burning gas & bullet friction.

I believe that, and WS2 cleans right out (far easier than carbon).
An advantage is in dry pre-fouling, with the first 5 shots being good and normal fouling taking over.

Somehow, WS2 can function as a 'universal' fowling.
If I were to shoot ~25 shots with a given powder, that gun would likely not shoot well with another powder until I've removed the 1st fowling, and refouled with the different powder. But, if I dry prefoul with WS2, I do not need to refoul for any different powder.

Another advantage, if bullets are also coated, is a strong mitigating of copper fouling.
I also like WS2 over other coatings, because it cleans out easy and it does not affect muzzle velocity.
So it's very easy to manage.

If I were to leave my bores uncleaned, in bad environments over time, then I can picture a cost for coating (like corrosion).
But that is never what I do.
If I take a gun out and shoot it once, or not at all, but subject it to bad conditions, then I fully clean it back at the house.
If I take it out of state for a week of hunting, I don't leave the gun in the back of my truck or anything. I treat it as well as my wife.
And when I get back home, I clean it.
Maybe that's why I've never had a problem with it.

 

[pdog shooter]

this is a shilen barrel with about 2000 22-250 thru. best I ever had, would shoot anything. best loads about 1.5 moa when barrel in condition below

 

[pdog shooter]

I can tell right away that you guys are way beyond my reloading level but I remember impact plating with HBN years ago. Not sure if it made any difference because it would be an automatic barrel swap after every p dog trip. Don't think that's been mentioned yet

 

[VinceMule]

In 1989, we found an unmolested p. dog town with compass and map, 11miles wide x 17 miles long. I shot the barrel out of a Seely Masker-made Custom with a Shilen barrel in one day, 800 hard fast rounds, I don't think I missed as the longest shot was 300 yards. IMR 4064 did a number on that Shilen barrel.

We started doing some research on which powders are easier on barrels, Win 760 was the winner at that time. Later on, AA2700 is the coolest burning powder made on the Heat Index chart, and the chart was not wrong in the many 22/250, AI, 243, AI, 220 Swifts, and 6 Rem and AI's that we shot out. AA2700 is in the burning rate of the 4350 area.

Bad day shooting at that time due to wind was around 600 centerfires and a normal day for me was 1000, while pard hammered out 1200 per day. We carried a five gallon bucket of ammo for each rifle, about 1200-2000 packed in Quart Glad freezer bags, rolled up tight with 100 rounds per bag. We simplified things after 4 years to a couple of cartridges, 223, 6 BR, 243 AI. All chambers cut with the same reamer, headspace the same.

After the first two years, we put Hart barrels on all guns as they cleaned up easier and the 416 Stainless steel sure takes the heat better than Chrome Moly barrels. Pard became a dealer for Hart barrels and we ordered them 10 at a time.

When Varmint Hunter magazine came out in 1993, that put an end to our p. dog shooting. From '79-1993 we hammered dogs hard. We then focused on Ground squirrels and Jack Rabbits.

No doubt that the 22/250 is an amazing round, easy to load for, accurate to 1/2" at 200 yards easily.

 

[sholm]

When looking at the charts - Do you think that the number of rounds can increase if sufficient time is always given between shots. Most of my shots(28 Nosler) are done in a manner where I shoot a round - walk to the target and back to mark it and then repeat - usually at least 3-5 minutes between shots when shooting at 200 yds and when shooting out to 600 longer. It takes me a while to get through a 10-12 shot session - I hoping that I'm extending the life of the barrel plus also simulating somewhat of first shot on a animal each time.

 

[Mikecr]

Do you think that the number of rounds can increase if sufficient time is always given between shots.

By letting the bore cool a bit, you won't shorten the accurate barrel life. But don't confuse that with gain.
Letting bore heat soak into outer barrel over a 1min shot rate will give you full life, but a 2min shot rate will not add to barrel life.

I think to gain accurate barrel life we would need a way to seal the surface of a bore -that doesn't hurt accuracy.
Something impervious to our heat, and flexible/durable enough to last.