Burn Rate Chart Inconsistencies

jski

jski

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I’m was looking for the relative (to other powders) burn rate for True Blue and so far I’ve found 58 from LoadData.com, 44 from Grafs.com, and 22 from hodgdonpowderco.com relative numbers where smaller means faster burning.

Some of this might be explained by there are different powders in the charts but the overlap of powders makes this a small contributor to explaining the large differences.

No doubt this inconsistency can be found with many powders. What’s the deal with this?
 
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I have not been able to arrive at a thing beyond similarities In burn rate and certainly must test a bit for myself before accepting IMR 4064 is exactly like Norm 202 just because they are next to one another on the chart.
 
Burning rates are considered approximate and vary depending on the parameters and conditions of the test. And a powder's behavior is influenced by the particulars of each cartridge. So a burn rate chart is really only useful for finding powders of similar burning characteristics that might be suitable for a given cartridge. If one cannot find pressure tested loading data for a particular powder/cartridge combination, it would be better to find a powder for which there is suitable data available.
 
The answer is pretty much encapsulated in the warnings on the charts, this is off the only one I have handy:
Burn rate charts can never reflect the differences between powders in the correct proportion, and can only place powders in approximate burn rate envelopes.
NEVER USE THESE TO DETERMINE/CALCULATE LOADS - ALWAYS REFER TO REPUTABLE LOAD GUIDES/MANUALS.

BBarn said:
Burning rates are considered approximate and vary depending on the parameters and conditions of the test. And a powder's behavior is influenced by the particulars of each cartridge. So a burn rate chart is really only useful for finding powders of similar burning characteristics that might be suitable for a given cartridge. If one cannot find pressure tested loading data for a particular powder/cartridge combination, it would be better to find a powder for which there is suitable data available.
Click to expand...
^ this.
 
jski said:
Some of this might be explained by there are different powders in the charts but the overlap of powders makes this a small contributor to explaining the large differences.
Click to expand...

"Faster" and "Slower" are qualitative, I don't know what unit of measure the MFG use to create a standard to deviate from or what tolerance +/- they allow or if different mfg's use the same standards.

That could make for things that are difficult to quantify. Probably why they are not even in the same order in all charts...
 
jski said:
No doubt this inconsistency can be found with many powders. What’s the deal with this?
Click to expand...

Industry wants ill informed consumers who make irrational choices. They are not going to put definitive information in the public domain that will allow the public to determine powder duplicates (HP38 & W231, W296 & H110), nor to show infinitely small differences between powders within groups.

Burn rate charts are appropriately vague, and while they have a gross utility, they are futile if you are "trying to measure to the thousandths with a wooden ruler".
 
I've never seen a powder vary that much. On Hodgdon's chart it's with the fast handgun powders between VV N310 and 320. On the loaddata.com chart it's on the opposite side of the spectrum and between N340 and 350.
 
AJC1 said:
True blue, long shot and Silhouette are all friends at the same camp. Hs-6 can also hang out.
Click to expand...
Those are all grouped close together on the loaddata.com chart. On the Hodgdon chart they are all grouped together except True Blue and it isn't even close.
 
There is no "industry standard" for measuring burn rates. Some burn the powder in the open. Others burn it in a pressure vessel.

As a result of differing testing methodologies, there can be no basis from which to compare one company's burn rate with another company's data.
 
GeoDudeFlorida said:
Burn rate charts are interesting, not informative.
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Nothing definitive can be gleamed by looking at a burn rate chart, but they are informative in the fact that they should show which powders have a similar burn rate. It doesn't mean they can use the same load data or even that powders next to one another will have same uses in similar cartridges. But it is odd to have a powder that jumps from a fast pistol powder in one chart to a moderately slow pistol powder in another chart. Is Is Ramshot True Blue slower or faster than Ramshot Zip? What about compared to other popular powders like Unique, Power Pistol or HP-38?
 
Fas
reddog81 said:
Nothing definitive can be gleamed by looking at a burn rate chart, but they are informative in the fact that they should show which powders have a similar burn rate. It doesn't mean they can use the same load data or even that powders next to one another will have same uses in similar cartridges. But it is odd to have a powder that jumps from a fast pistol powder in one chart to a moderately slow pistol powder in another chart. Is Is Ramshot True Blue slower or faster than Ramshot Zip? What about compared to other popular powders like Unique, Power Pistol or HP-38?
Click to expand...
Faster than zip, just a tiny bit slower than Silhouette. Over two full grains faster than blue dot in 357...
 
reddog81 said:
Nothing definitive can be gleamed by looking at a burn rate chart, but they are informative in the fact that they should show which powders have a similar burn rate. It doesn't mean they can use the same load data or even that powders next to one another will have same uses in similar cartridges. But it is odd to have a powder that jumps from a fast pistol powder in one chart to a moderately slow pistol powder in another chart. Is Is Ramshot True Blue slower or faster than Ramshot Zip? What about compared to other popular powders like Unique, Power Pistol or HP-38?
Click to expand...
Information vs Inference. Information is based on repeatability and accuracy. Inference is based on logical deduction.

If I can use one set of tests and instrumentation and come up with the same chart as every lab, that is informative. If I have to adjust my testing to come up with a comparable chart, that is inference. I can infer from one chart the results of another.

Burn charts are neither informative nor inferential; but they are interesting.
 
GeoDudeFlorida said:
Information vs Inference. Information is based on repeatability and accuracy. Inference is based on logical deduction.

If I can use one set of tests and instrumentation and come up with the same chart as every lab, that is informative. If I have to adjust my testing to come up with a comparable chart, that is inference. I can infer from one chart the results of another.

Burn charts are neither informative nor inferential; but they are interesting.
Click to expand...
I've never seen a loading which does not conform to the pattern I've seen in another. Blue dot is slower in 357 than Longshot and the same is true in 10mm. I've not seen a loading where that is diffrent.
 
AJC1 said:
I've never seen a loading which does not conform to the pattern I've seen in another. Blue dot is slower in 357 than Longshot and the same is true in 10mm. I've not seen a loading where that is diffrent.
Click to expand...
Soooo. You’re saying a lack of evidence of an observation is conclusive evidence of an observable fact?
That’s an interesting form of logic.

I think I’ll check out of the discussion now before we start trying to convince each other of something because it’s a popular opinion to have.
 
I don’t put much stock in burn rate charts because of the inconsistency in them . I mainly use them as one other person said to find a powder that is somewhat close to what I was using and can’t find it . Example being I love 700X but it’s just not available so I looked at a burn chart and picked American Select for a replacement and I really like it maybe even better than 700X .
 
AJC1 said:
True blue, long shot and Silhouette are all friends at the same camp. Hs-6 can also hang out.
Click to expand...
Except when Silhouette gets cold he gets mean. The others only get angry when it’s hot out.

How things like this occur are magical to me. And like Slam said, it’s in the companies interests to keep us less than informed, so I continue to be mystified.
 
GeoDudeFlorida said:
Information vs Inference. Information is based on repeatability and accuracy. Inference is based on logical deduction.

If I can use one set of tests and instrumentation and come up with the same chart as every lab, that is informative. If I have to adjust my testing to come up with a comparable chart, that is inference. I can infer from one chart the results of another.

Burn charts are neither informative nor inferential; but they are interesting.
Click to expand...
Various powders behave slightly different under differing circumstances. Change the case size, pressure, temperature and you can change how relatively fast or slow a powder burns. However the results should be repeatable using the same parameters as the original tester. Change parameters and you end up with different results, yet they are still repeatable by someone else using new those identical parameters

Saying they are interesting but not informative makes it sound like the results are just fiction. FWIW the definition of informative is providing useful or interesting information.
 
Some maybe too close to call. Then there is lot variance and testing variance. H-110 and W-296 along with W-231 and HP-38 are said to be the same, even by Hodgdon but load data treats these as separate powders:cuss:Were these powders always the same or did something change?
 
Demi-human said:
Except when Silhouette gets cold he gets mean. The others only get angry when it’s hot out.

How things like this occur are magical to me. And like Slam said, it’s in the companies interests to keep us less than informed, so I continue to be mystified.
Click to expand...
How cold we talking, broc shot a match at about 40, and I don't go below that. Now we're even further south, so I'm interested from a technical standpoint, but it won't apply.
 
reddog81 said:
Various powders behave slightly different under differing circumstances. Change the case size, pressure, temperature and you can change how relatively fast or slow a powder burns. However the results should be repeatable using the same parameters as the original tester. Change parameters and you end up with different results, yet they are still repeatable by someone else using new those identical parameters

Saying they are interesting but not informative makes it sound like the results are just fiction. FWIW the definition of informative is providing useful or interesting information.
Click to expand...
A chart is for those who haven't used them all yet. I happen to still be one of those guys, but not for long...
 
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