Honest questions about bullet coating(s)

[TAJ45]

I've been instructed on waxing, read about Danzac and moly.

Mentally I'm trying to reconcile the idea of needing more powder to maintain the velocity when using moly. Is this the same for Danzac? More powder = more throat erosion apples to apples it would seem.

What are the thoughts of these mentioned plus whatever else is out there I'm not aware of?

NOT wanting to start a Ford/Chev/Moly/Danzac war, just gathering input please.

Pros and cons welcomed along with personal experience.

 

[jonbearman]

When you use danzac,moly,or HBN which is what I use reduces friction so to get speed up you will have to add possibly a half grain of powder.

 

[TAJ45]

Thanks John. What size case is this for? I'm assuming somewhat proportioanal to capacity/grains used? Would a % increase of X load be a good rule of thumb?

 

[Keith Glasscock]

Not really a percentage per se, In my 284, the velocity change (measured) was only a few fps (like 25) when going from naked to HBN. That said, the HBN didn't have very many rounds to get settled in - only 20 or so.

Different powders will have different characteristics. For example, there is an absolute cliff in the velocities of H4350 in my 284. In a very small charge change, (0.7%) I get surprising increases in velocity (like 30-40 fps).

The real answer is that everything has to be determined experimentally.

 

[stool]

word games with the same out come.

moly does NOT reduce pressure.
moly reduces friction.
reduced friction allows a moly bullet to move further/faster than a naked bullet.
this happens very fast..and basically increases the volume of the combustion chamber.....
(case volume, plus where the bullet meets its first real resistance)
this larger combustion chamber produces less pressure for the original load, and thus less velocity.

same out come, different words.

 

[brian427cobra]

I have noticed that none of the people I shoot with(most are in the PRS) shoot non coated bullets, and none of the people in my Club shoot coated bullets in 100/200 Benchrest, including the world record holder at 100, in my personnel experience of coating 155s with HbN, I chose not to coat or shoot coated bullets anymore, to me the time and expense are not worth the perceived benefits, which in my IMHO are nil.

 

[stool]

15 plus years of coated bullets.
mostly moly, and now some hbn.
basically all rifles get coated bullets but one swede.

shoot the same longer...pretty simple.
time and effort to produce coated bullets.
a tad more powder to get to a sweet spot.
i clean with chemicals..no metal brushes....

 

[tenring]

The coatings mentioned mayincrease barrel life expectancy.

 

[mikegaiz]

If you choose Molly? Use the wet application method. I have used molly for years and the wet process is a totally better and different animal. No wax required.

 

[Nomad47]

I use hBN. The bullets and the bore get coated. I don't use chemicals or wire brushes to clean, just dry patches with an occasional nylon brush.

 

[Michael Courtney]

http://www.dtic.mil/dtic/tr/fulltext/u2/a568594.pdf

We've published the most quantitative assessment of whether or not the popular coatings significantly reduce barrel friction. Short answer: they don't really. Long answer: read the paper.

 

[Michael Courtney]

Our method does not assume anything. The powder we use is a very fast powder which has been proven to have an exactly linear relationship between powder charge and muzzle energy. Most slower powders are non-linear in their response because of the non-linearity in their burn rates.

There is a popular theory that the lubricant is causing the bullet to enter the lands with less resistance effectively increasing the size of the combustion chamber and causing a reduction in velocity due to the non-linear combustion properties of nitrocellulose. Your paper doesn't mention this theory. Do you think it is bunk?

Hard to even call this explanation a theory since there is no data clearly supporting it. Reducing muzzle velocity is no proof of reducing friction, because with most powders, there is no way to know whether the reduced friction reduces the burn efficiency (thus lowering muzzle energy) more than reduced friction raises muzzle energy by requiring less work to push the bullet through the rifling.

By choosing a powder whose efficiency is not sensitive to the detailed internal ballistics, the only variable is how much energy is lost pushing the bullet through. Thus the work done by friction is accurately determined, and the lubricants do not reduce the work required to push the bullet through the barrel.

 

[waterdog]

My opinion; I have used Tungsten Disulfide (danzak) for years. My son uses it as well as James Coffey and several others. We all do 600yd bench rest. It doesn't seem to build up in the barrel and we don't get any copper fowling. I usually clean when I get home from the match or sometime before next months match. Never clean at the match. Have shot as many as two matches without cleaning (approx. 175 rds.) Our barrels are still competitive at 2500 rds. or more.
I am and old man set in my ways so I hate to change now. Having lots of fun.
Larry Isenhour

 

[stool]

simple question.

WHY DOES A GIVEN RIFLE LOAD PRODUCE LESS VELOCITY WHEN A MOLY COATED BULLET IS USED IN PLACE OF A BARE COPPER BULLET ??


IF YOU CANNOT EXPLAIN THAT ACTUAL FACT, ME THINKS YOUR PAPER IS USELESS.

Our method does not assume anything. The powder we use is a very fast powder which has been proven to have an exactly linear relationship between powder charge and muzzle energy. Most slower powders are non-linear in their response because of the non-linearity in their burn rates.

There is a popular theory that the lubricant is causing the bullet to enter the lands with less resistance effectively increasing the size of the combustion chamber and causing a reduction in velocity due to the non-linear combustion properties of nitrocellulose. Your paper doesn't mention this theory. Do you think it is bunk?

Hard to even call this explanation a theory since there is no data clearly supporting it. Reducing muzzle velocity is no proof of reducing friction, because with most powders, there is no way to know whether the reduced friction reduces the burn efficiency (thus lowering muzzle energy) more than reduced friction raises muzzle energy by requiring less work to push the bullet through the rifling.

By choosing a powder whose efficiency is not sensitive to the detailed internal ballistics, the only variable is how much energy is lost pushing the bullet through. Thus the work done by friction is accurately determined, and the lubricants do not reduce the work required to push the bullet through the barrel.

 

[stool]

YOU APPEAR TO BE A TYPICAL TAXPAYER MONEY WASTER.

NO ONE USES .9 grams or less of a fast burning powder in 223/5.56 with copper jacketed bullets
the criteria of your so called test is unreal,
meaning the outcome is just garbage,,,,
garbage in , garbage out.

waste of time and tax payer money....

http://www.dtic.mil/dtic/tr/fulltext/u2/a568594.pdf

We've published the most quantitative assessment of whether or not the popular coatings significantly reduce barrel friction. Short answer: they don't really. Long answer: read the paper.

 

[johara1]

I don't get any copper fouling, i get the velocity i need and they shoot small, gave up on HBN tried it on bags didn't do any better there. It just sits on the shelf holding the jar down, i had to try it, but i didn't see anything to improvement or change……… zip……….. jim

 

[Michael Courtney]

simple question.

WHY DOES A GIVEN RIFLE LOAD PRODUCE LESS VELOCITY WHEN A MOLY COATED BULLET IS USED IN PLACE OF A BARE COPPER BULLET ??


IF YOU CANNOT EXPLAIN THAT ACTUAL FACT, ME THINKS YOUR PAPER IS USELESS.

Our method does not assume anything. The powder we use is a very fast powder which has been proven to have an exactly linear relationship between powder charge and muzzle energy. Most slower powders are non-linear in their response because of the non-linearity in their burn rates.

There is a popular theory that the lubricant is causing the bullet to enter the lands with less resistance effectively increasing the size of the combustion chamber and causing a reduction in velocity due to the non-linear combustion properties of nitrocellulose. Your paper doesn't mention this theory. Do you think it is bunk?

Hard to even call this explanation a theory since there is no data clearly supporting it. Reducing muzzle velocity is no proof of reducing friction, because with most powders, there is no way to know whether the reduced friction reduces the burn efficiency (thus lowering muzzle energy) more than reduced friction raises muzzle energy by requiring less work to push the bullet through the rifling.

By choosing a powder whose efficiency is not sensitive to the detailed internal ballistics, the only variable is how much energy is lost pushing the bullet through. Thus the work done by friction is accurately determined, and the lubricants do not reduce the work required to push the bullet through the barrel.

Can you provide actual data from a repeatable experiment complete with pressure curves?

Pressure curves of the moly coated case and the uncoated case are necessary to answer your question, along with full specs: case, powder, bullet, rifle, etc.

We've seen different brass, different primers, different powder lots, changes in atmospheric pressure or the storage conditions of the powder have significant impacts on muzzle velocity. Good science knows that all the possible confounding factors need to be held constant.

We've published the data and full experimental method that support our conclusions. Where can we find the data and full experimental method that support your claims?

No one has ever published compelling data showing that moly reduces barrel friction. We have found that it does not using a repeatable and accurate method to determine the average force of friction in the barrel.

 

[stool]

why is this "paper" a joke ??
powder choice: blue dot.
velocity limit: aprox 2600 fps vs the std of 3165 for a 55 gr bullet.
case fill: at max it was 49% vs the typical 90% plus seen normally.
case powder charge: max was 14 gr vs the typical load of 20 plus gr
operating pressure: a mere 42kpsi vs the normal 54k plus seen in normal 55 fmjbt ammo.
muzzle pressure: is 5500 from a 20" bbl vs 9000psi from a std 55 gr load
bbl pressure is under 10kpsi for the last 8 inches, while a std 55 load never falls below 10kpsi

this test/paper has nothing to do with the reality seen by active shooters with normal loads...NOTHING!


did you guys read norma's paper or talk to norma before wasting everyone's time and money ??

http://www.dtic.mil/dtic/tr/fulltext/u2/a568594.pdf

We've published the most quantitative assessment of whether or not the popular coatings significantly reduce barrel friction. Short answer: they don't really. Long answer: read the paper.

 

[stool]

you did not answer the question
it is a known published FACT.
MULTIPLE DATA POINTS OVER MULTIPLE CHRON0GRAPHS......

simple question.

WHY DOES A GIVEN RIFLE LOAD PRODUCE LESS VELOCITY WHEN A MOLY COATED BULLET IS USED IN PLACE OF A BARE COPPER BULLET ??


IF YOU CANNOT EXPLAIN THAT ACTUAL FACT, ME THINKS YOUR PAPER IS USELESS.

Our method does not assume anything. The powder we use is a very fast powder which has been proven to have an exactly linear relationship between powder charge and muzzle energy. Most slower powders are non-linear in their response because of the non-linearity in their burn rates.

There is a popular theory that the lubricant is causing the bullet to enter the lands with less resistance effectively increasing the size of the combustion chamber and causing a reduction in velocity due to the non-linear combustion properties of nitrocellulose. Your paper doesn't mention this theory. Do you think it is bunk?

Hard to even call this explanation a theory since there is no data clearly supporting it. Reducing muzzle velocity is no proof of reducing friction, because with most powders, there is no way to know whether the reduced friction reduces the burn efficiency (thus lowering muzzle energy) more than reduced friction raises muzzle energy by requiring less work to push the bullet through the rifling.

By choosing a powder whose efficiency is not sensitive to the detailed internal ballistics, the only variable is how much energy is lost pushing the bullet through. Thus the work done by friction is accurately determined, and the lubricants do not reduce the work required to push the bullet through the barrel.

Can you provide actual data from a repeatable experiment complete with pressure curves?

Pressure curves of the moly coated case and the uncoated case are necessary to answer your question, along with full specs: case, powder, bullet, rifle, etc.

We've seen different brass, different primers, different powder lots, changes in atmospheric pressure or the storage conditions of the powder have significant impacts on muzzle velocity. Good science knows that all the possible confounding factors need to be held constant.

We've published the data and full experimental method that support our conclusions. Where can we find the data and full experimental method that support your claims?

No one has ever published compelling data showing that moly reduces barrel friction. We have found that it does not using a repeatable and accurate method to determine the average force of friction in the barrel.

 

[stool]

you never got to NORMAL operating PRESSURE for a normal 55 gr load.
since you never got to NORMAL...you saw no useful DATA.....NONE.
YOU CANNOT TELL HOW A 55GR BULLET REACTS AT THE THROAT AT NORMAL PRESSURE.....
YOU NEVER GOT THERE!
your "so called" CRITERIA are a joke....

http://www.dtic.mil/dtic/tr/fulltext/u2/a568594.pdf

We've published the most quantitative assessment of whether or not the popular coatings significantly reduce barrel friction. Short answer: they don't really. Long answer: read the paper.