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Honest questions about bullet coating(s)

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

Michael Courtney said:
stool said:
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.

Michael Courtney said:
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.

We took care in our experiments to use the same lot of all components and the same chronograph. Data was taken under the same environmental conditions. We found that in most cases where a coating reduces muzzle velocity, it is because of increased friction.

A bullet in a barrel is has a propelling force (the burning powder) and a resisting force (the friction). If the friction is increased, the bullet loses muzzle velocity. Explaining internet claims of others is difficult without knowing all the facts. There are a number of confounding factors that could explain reported observations of moly reducing muzzle velocities. It could be increased friction. It could be decreased friction. It could be a change in lot number of one of the components or storage conditions of the powder or a change of primer.

How much sense does it make to demand that a scientist explain reports that he does not have full information on? And then to scoff when he asks for more details? Just because you've heard something many times does not make it true.
 
i see nothing in your "paper" where you inspected the bore to ensure IT was coated.
shooting coated bullets is a system which includes both the bullet and the bbl.

shooting in a production bbl may take 20 to 40 shots to properly coat the bbl....it maybe so poor, it may not help at all.

all your high quality test procedures and you use a run of the mill bbl !

the more i read the funnier it gets....
 
known proven facts of coated bullets
longer sustained performance.....you shoot the same accuracy longer.
extended bbl life (norma)
velocity drops with a coated bullet.

the problem with your proposal that friction is increased is that bbl life would not increase with increased friction.

all of my personal testing, every published report shows a decrease in velocity when a simple change from uncoated to coated bullets.

in my case same day same lots of powder, brass, primers and bullets. quality products in each case...lapua brass, vith powder, berger bullets.......
my chronograph is a 35p while older does use 4' spacing. the numbers do not lie...
BUT then i used real world parts and pieces.....not blue dot!

again your information is unrealistic and is of no use to a modern reloader using NORMAL LOADS AND PRESSURES.

why did you stop at such a low pressure, such a low velocity ?? did you not know where the real world was ??

Michael Courtney said:
Just because you've heard something many times does not make it true.
 
stool said:
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....

Michael Courtney said:
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.

If (as you assert) barrel friction depends on operating pressure, there is no way bullet energy would show such a strong (near perfect) linear dependence on powder charge over such a wide range of powder charges (6-14 grains) for so many different bullets.

Further, with a "normal" load, max chamber pressure isn't reached until the bullet is 1 to 1.5 inches down the barrel. The pressure as the bullet is traversing the throat is less than 40,000 psi, just as it is with Blue Dot. The faster burning Blue Dot reaches comparable pressures to ball military powders during the time when the bullet is traversing the throat.

Finally, our friction numbers are comparable with the results of White and Siewert when using the same bullet (the M855). They pushed bullets through with a rod and measured the forces with a load cell. We pushed the bullets through with burning Blue Dot. If the friction differences between pushing with a rod and Blue Dot are small, is it that big a stretch to believe the differences between Blue Dot and more common 5.56mm powders are also small?

If there is hard data showing that coatings really reduce friction, it would be a valuable addition to the conversation. For example, if muzzle velocities are reduced and you can also provide pressure curves that are also reduced by a commensurate amount, this would support a reduction of friction in that given case. However, if muzzle velocities of coated bullets are reduced, but measured pressure curves show increased pressure, then it is clear that friction has been increased by the coating.

However, my experience is that those firm in their preconceptions are usually unable to support their position with real scientific data.
 
i see nothing in your procedures where you weight sorted the bullets....production bullets can easily vary in a single lot.
plus or minus 0.3gr is the std for one large high quality bullet maker..a 6 tenths variation on a 55gr test could easily skew the results.

i see nowhere where you measured bearing length. bearing length is directly related to friction in a given shot. in custom bullets i have seen 8 tenths variation in a single lot. variation in bearing length means a variation in friction.....you never account for this in your information paper.

i do not need pressure readings to see VELOCITY . that is what a chronograph is for.
 
"Further, with a "normal" load, max chamber pressure isn't reached until the bullet is 1 to 1.5 inches down the barrel. The pressure as the bullet is traversing the throat is less than 40,000 psi, just as it is with Blue Dot. The faster burning Blue Dot reaches comparable pressures to ball military powders during the time when the bullet is traversing the throat."

the difference between 24kps at the throat and 20kpsi of bluedot is 20% more pressure .......

but i guess 20% is close enough for government work
 
one final statement and then i am done on this thread.

the mentioned report, IN MY OPINION, has no useful data for the modern shooter shooting a coated bullet system in normal operating pressures.
 
Stool...by the way, good name
Moly and other dry lubricants reduce friction...period. That's why machines with tight tolerances and a continuous work load use them. It keeps the production up and machine ware down. Do you think bullets and barrels are of a different nature? If you want inside info on moly ask Norma, or Berger, they seem to think so much of them they work them into their target line of bullets...also Lapua and Sierra. They would not spent the time, money and effort if they so no benefit.
 
stool said:
i see nothing in your procedures where you weight sorted the bullets....production bullets can easily vary in a single lot.
plus or minus 0.3gr is the std for one large high quality bullet maker..a 6 tenths variation on a 55gr test could easily skew the results.

I guess you missed the paper where we compare bullet weight variations with manufacturer specifications.

See: http://www.dtic.mil/dtic/tr/fulltext/u2/a555976.pdf

Berger's spec is +/- 0.1 grains for their 62 grain bullets, and the Berger bullet we used was measured on a precision laboratory scale and shown to meet the spec. The other bullets we tested were not as tight with their weight tolerances, but the single digit uncertainties we measured in the average velocities show that weight and dimensional variations did not skew our results in any way.

Weight and dimensional variations certainly can have effects in friction and muzzle velocity, but our consistent muzzle velocities and small uncertainties show that our results were not negatively impacted by the small dimensional and weight variations of the bullets we choose. We did see a bad box of Nosler Ballistic Tips with weight variations (standard deviation) of over 0.1 grains, but most boxes are under 0.05 grains. The box of 50 TTSX bullets we used had a weight standard deviation of 0.068 grains, as determined from measuring every bullet on a precision laboratory scale. There are bullets out there with much larger variations in weight and dimensions, but we've measured thousands of bullets, and we choose appropriate bullets for this experiment.
 
madderg said:
Stool...by the way, good name
Moly and other dry lubricants reduce friction...period. That's why machines with tight tolerances and a continuous work load use them. It keeps the production up and machine ware down. Do you think bullets and barrels are of a different nature? If you want inside info on moly ask Norma, or Berger, they seem to think so much of them they work them into their target line of bullets...also Lapua and Sierra. They would not spent the time, money and effort if they so no benefit.

There is a definite marketing benefit, and there does seem to be a benefit in many barrels with respect to reducing fouling. Reduced friction? No, not really.
 
Not sure where they got their info, but Lyman stated in one of their loading manuals that coated bullets had a small percentage of velocity drop over uncoated bullets BUT the pressure decrease was a slightly larger percentage. Therefore, if the charge was increased back to the original pressure of the uncoated bullet, velocity of the coated bullet would be higher than the uncoated bullet.
 
Nomad47 said:
Not sure where they got their info, but Lyman stated in one of their loading manuals that coated bullets had a small percentage of velocity drop over uncoated bullets BUT the pressure decrease was a slightly larger percentage. Therefore, if the charge was increased back to the original pressure of the uncoated bullet, velocity of the coated bullet would be higher than the uncoated bullet.

This is a common assertion, but we've never found it backed up with measured pressure curves. If the pressure curves were not measured, it is just a guess, not a real explanation. The explanation may sound consistent with the assumption that coatings reduce friction, but the pressure curves themselves (with and without the coating) are needed to be sure.
 
Doesn't matter. Coating works for me and I will keep right on coating my bullets AND bore. My barrels were borescoped by a fellow forum member, and he said they looked like they had one hundred or so rounds thru them instead of the actual 1000 rounds.
 
Nomad47 said:
Doesn't matter. Coating works for me and I will keep right on coating my bullets AND bore. My barrels were borescoped by a fellow forum member, and he said they looked like they had one hundred or so rounds thru them instead of the actual 1000 rounds.

If your goal is improved barrel life, you may be right.

But the claim of reduced friction and reduced pressure so you can safely add more powder is problematic from a safety point of view, since the claim of lower pressure is unverified.

Do any bullet manufacturers recommend higher max loads for their bullets when they are coated? Do any of the powder manufacturers recommend higher max loads when using their powders with coated bullets? Yet many times I've heard that when one switches from uncoated to coated bullets, a reloader can safely add powder until he reaches the velocities achieved with uncoated bullets.

The Martin patent (EP19990306437) even claims that MS2 allows for safe velocity increases of 2-5% and that WS2 allows for safe velocity increases of 5-10% "at normal pressures." A 10% gain in velocity at "normal pressures" would require a 50% reduction in barrel friction.

If your goal is longer barrel life or improved accuracy, you may be fine. Our experiments were not designed to test these claims. If your goal is reduced friction, the bullet coatings fall far short of the claims in the patent.
 
Safe reloading practices dictate you start over when changing ANYTHING, including switching from uncoated to coated bullets. So anyone that switches from uncoated to coated bullets AND increases the charge is a fool.
 
I might be able to muddy the waters a tad, BUT Im just extrapolating info/ data. Blue Dot is described as being linear in burn rate, however or but, Alliant has stringently advised that it not be used in creation of certain handgun loads. I dont know the particulars, but this does suggest that there are unexplained excursions of pressure. Combinations of certain bullet weight in certain calibers………………? And to add more to the confusion, cast bullets V. jacketed in handguns, Lyman #49 is the resource here. They are using a universal receiver raher than a revolver or vented system. Frequently cast bullets produce more velocity than jacketed while using the same or closely similar powder charges. And I know that I can push a cast bullet through a barrel with moderate force, but I aint about to try that with a jacketed bullet. Single base powders are linear in burn /pressure/velocity curves(I have so Read, in manuals and info put forth by manufacturers). So now I can say Im utterly befuddled by the "findings" put forth here. Ive used WS2 for quite a while and like the lack of fouling and the extended shooting strings it "SEEMS" to provide. I haven't paid much attention to any additional propellant requirements since Ive only worked up the load once. 223. 22BR, 308, 6X44, 7mmWSM, 300WSM, 6.5-284 all have been coated. All except the 6.5 "seemed" to respond favorably. I guess Ill keep using the WS2, Im thinking of trying the hBN I've got the first trial didn't coat as I expected. Any how can this all be explained?
 
rogn said:
I might be able to muddy the waters a tad, BUT Im just extrapolating info/ data. Blue Dot is described as being linear in burn rate, however or but, Alliant has stringently advised that it not be used in creation of certain handgun loads. I dont know the particulars, but this does suggest that there are unexplained excursions of pressure. Combinations of certain bullet weight in certain calibers………………? And to add more to the confusion, cast bullets V. jacketed in handguns, Lyman #49 is the resource here. They are using a universal receiver raher than a revolver or vented system. Frequently cast bullets produce more velocity than jacketed while using the same or closely similar powder charges. And I know that I can push a cast bullet through a barrel with moderate force, but I aint about to try that with a jacketed bullet. Single base powders are linear in burn /pressure/velocity curves(I have so Read, in manuals and info put forth by manufacturers). So now I can say Im utterly befuddled by the "findings" put forth here. Ive used WS2 for quite a while and like the lack of fouling and the extended shooting strings it "SEEMS" to provide. I haven't paid much attention to any additional propellant requirements since Ive only worked up the load once. 223. 22BR, 308, 6X44, 7mmWSM, 300WSM, 6.5-284 all have been coated. All except the 6.5 "seemed" to respond favorably. I guess Ill keep using the WS2, Im thinking of trying the hBN I've got the first trial didn't coat as I expected. Any how can this all be explained?

When anything is described as "linear" you need to pay careful attention to precisely which two variables are linearly related. Blue Dot is probably not "linear" in its relationship between burn rate and pressure. It may not produce a linear relationship between muzzle energy and powder charge in handgun calibers. We have found it does produce a linear relationship between muzzle energy and powder charge in .223 Rem/5.56 NATO and .222 Rem. This linearity holds over a wide range of powder charges.

These are experimental results that allow determination of the average frictional forces in the barrel. It does not really address theoretical questions regarding why the powder demonstrates a nearly perfectly linear relationship between muzzle energy and powder charge or how the powder might behave in other applications. It does provide the most accurate method available for quantifying barrel friction for different combinations of bullet, barrel, and coating in .223 Rem/5.56 NATO and .222 Rem.
 
I drank the Molly cool-aid back in the 80's. I do not have a scientific back ground, but have an applied knowledge of the product. Molly has changed over the years, The new "Water Application" process has really improver the overall product from what I can see. No messing with the coating thickness, finish, wax and weather wax had anything to do with the overall outcome. the water method puts on a mirror smooth finish. For a while people even mixed molly in the powder charge, and sprayed on a coating, sprayed in in their barrels. I shot molly in competition (1000 yds.) for a while, but could get a good cleaning regiment to work so stopped using it in competition. But have always used it for every thing else.

It has proven it self to me over the years in prairie dog shooting. I shoot 2000 to 5000 a year for most of the past 20 + years. I have one gun that has been a long time testbed for molly. It is a 28 in. Hart barrel chambered in standard 243 Win. no turn neck. I have only shot Molly coated 85 HPBT Sierra bullets and H-380 ball powder 36.5 gr. around 3000 Fps. To date the barrel has over 3500 shots through it and it will still shoot under 1 in. groups at 100 yds. I think that is almost unheard of for a 243. Not sure if Molly is the reason alone or the Ball powder has something to do with it. Or the two combined have produced these results. That is my story, I have the gun to prove it and I am sticking to it. 8)

Almost forgot, I have had to increase the powder charge about 1 gr. to get the same velocity with a coated bullet as an non-coated bullet in my 243. And that has held true for most calibers.
 
mikegaiz said:
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.

Agreed. IMO, the wet application method is the ONLY way to use moly. I wouldn't even mess with it as a dry coating. The difference in the end product between the the two methods is night and day. Dry can be rubbed off easily, the wet is etched into the bullet jacket material and is much more durable.

I don't shoot 5k rounds/year at PD's like Mr mikegaiz does, but I shoot several hundred and for some reason my moly'ed barrels show much less wear than the naked bullet barrels. AND yes, I have to add more powder with a wet molyed load to equal the chrono readings of a naked bullet load.
 
MC, I realize you are trying to be evenhanded in your research. But your statement that your protocol is the "best method available" becomes an overreach and defensive of the protocol. Better stated, it was the best method we could derive. Complexities and variables in this issue range to the "nth" degree. Testing and recording gets expensive and time consuming also to the same degree. A 110 barrels a dozen cartridges a hundred bullets and 2 dozen powders might be more real world representative. Not condemning just questioning. ? Could some compressed gas system such a PCP be a more consistant mode for this research. Pressure constant, velocity could/ should be very linear. Friction +/_ should be very clear.
 

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