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Am guessing this has been shared before and I am conmvinced some know it by heart- but I thought I would share anyway. It is pretty complete. http://www.reloadbench.com/burn.html
When a country is well governed, poverty and a mean condition are something to be ashamed of. When a country is ill governed, riches and honors are something to be ashamed of
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Taken from chuckhawks.com- an article by Randy Wakeman titled
"Why Burn Rates Are Meaningless"
Perhaps you have looked at various "Burn Rate Charts" and wondered what good they are. Well, you have good reason to wonder. Burn rate charts seldom agree. There is no specific meaning for "burn rate," so it shouldn't surprise us that the numbers don't agree. They mean nothing by themselves.
What amateurs call burn rate is not used by professional ballisticians to develop loads. The actual term closest to burn rate used in interior ballistics is "Relative Quickness."
Relative quickness is defined by "closed bomb tests," which quantify pressure rise in a sealed container. However, professional ballisticians do not use relative quickness for load development, either. A closed bomb relative quickness value does not translate into any type of value outside of that 'closed bomb' test. Powder performance varies widely by actual application. Relative quickness is one of several preliminary considerations when assessing a powder's suitability for a particular application by ballistics, but nothing more than that.
Relative quickness does not tell use the physical shape of a powder, its composition, or the types of coatings. It cannot tell us whether a powder is single-based, double based, or triple based. It does not tell us the heat of explosion, the progressive / degressive gas creation values, the ignition characteristics, and so forth. There is no way to translate a double-based powder performance into a single-based powder performance level with any accuracy. Even further, relative quickness does not define the erosiveness of a powder, the residue left by a powder, its ability to meter properly; and on it goes.
Energy content of nitrocellulose varies by manufacturer. It varies by the amount of nitrogen in the nitrocellulose. The more nitrogen, the more gas a powder can make. Once you have a specific type of nitrocellulose the energy content is further controlled by the addition of nitroglycerin, which is basically what constitutes a double-based powder. Now you have further considerations, as nitrocellulose and nitroglycerin do not behave the same way as temperature changes. The amount of nitro percentage varies by powder to powder, and with it its performance in a specific application.
All this combines to make burn rate charts something to ignore, or to view with very little importance placed on them. Professional ballisticians do not use them at all, simply because they have no particular meaning. Ping-Pong balls are nitrocellulose, but not many of us would bother cutting them up and attempting to use them in a firearm.
Last edited by kenjs1; 01/04/13.
When a country is well governed, poverty and a mean condition are something to be ashamed of. When a country is ill governed, riches and honors are something to be ashamed of
. Confucius
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With all due respect to Chuckhawks, I am not a professional ballistician, and I use the burn rate chart to identify potential overlaps when I am considering a new powder to invest in. I certainly don't use them to discern charge weights or anything else, but it's nice to know where a powder sits relative to it's competitors.
Regards,
Tom
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I agree with tominboise, I to use these charts. Knowing a powders "relative quickness" is useful. In defense of Chuckhawks there are a few powders that have varied positions depending on the chart you refer to, and some that shoot well in calibers in spite of being outside of the optimum burn rate. However that does not make the charts something to ignore. Like allot of the information out there, it's there to help us make decisions, come to our own conclusions, use our brains.
If I had a pet peeve it would probably be that too many of us are too quick to share our opinions on forums, without the experience to back it up. I can respect "I tried that and it didn't work out for me" allot more than an opinion. Forums are a good resource, to share experience, and failing that, to at least get some varied opinions.
My opinion and experience is that burn rate charts are useful, perhaps not gospel, but useful all the same.
I do wonder where CFE 223 would be in "the" chart, my opinion is that it is close to BLC-2, requiring a bit more powder to achieve the same pressure, usually giving the same or slightly more velocity. I've used it in the 22-250, 8x57 and 350 RM, can't say Ive noticed any less copper, but it does give uniform velocities, and some pretty fast load without excess pressure.
Time to step off the soap box.
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Taken from chuckhawks.com- an article by Randy Wakeman titled
"Why Burn Rates Are Meaningless"
Perhaps you have looked at various "Burn Rate Charts" and wondered what good they are. Well, you have good reason to wonder. Burn rate charts seldom agree. There is no specific meaning for "burn rate," so it shouldn't surprise us that the numbers don't agree. They mean nothing by themselves.
What amateurs call burn rate is not used by professional ballisticians to develop loads. The actual term closest to burn rate used in interior ballistics is "Relative Quickness."
Relative quickness is defined by "closed bomb tests," which quantify pressure rise in a sealed container. However, professional ballisticians do not use relative quickness for load development, either. A closed bomb relative quickness value does not translate into any type of value outside of that 'closed bomb' test. Powder performance varies widely by actual application. Relative quickness is one of several preliminary considerations when assessing a powder's suitability for a particular application by ballistics, but nothing more than that.
Relative quickness does not tell use the physical shape of a powder, its composition, or the types of coatings. It cannot tell us whether a powder is single-based, double based, or triple based. It does not tell us the heat of explosion, the progressive / degressive gas creation values, the ignition characteristics, and so forth. There is no way to translate a double-based powder performance into a single-based powder performance level with any accuracy. Even further, relative quickness does not define the erosiveness of a powder, the residue left by a powder, its ability to meter properly; and on it goes.
Energy content of nitrocellulose varies by manufacturer. It varies by the amount of nitrogen in the nitrocellulose. The more nitrogen, the more gas a powder can make. Once you have a specific type of nitrocellulose the energy content is further controlled by the addition of nitroglycerin, which is basically what constitutes a double-based powder. Now you have further considerations, as nitrocellulose and nitroglycerin do not behave the same way as temperature changes. The amount of nitro percentage varies by powder to powder, and with it its performance in a specific application.
All this combines to make burn rate charts something to ignore, or to view with very little importance placed on them. Professional ballisticians do not use them at all, simply because they have no particular meaning. Ping-Pong balls are nitrocellulose, but not many of us would bother cutting them up and attempting to use them in a firearm.
Long winded sumbitch... I use burn rate charts to work up loads all the time. If it were as complicated as he pretends it is, they wouldn't sell the schit for $25.00 a pound. Travis
Trump being classless,tasteless and clueless as usual. Sorry, trump is a no tax payin pile of shiit. My young wife decided to play the field and had moved several dudes into my house
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ken, That's a good one. I like this one as well from Ramshot's site. I like the side by side comparison a little better. http://www.ramshot.com/wp-content/uploads/2010/12/burn_rates.pdfTravis
Trump being classless,tasteless and clueless as usual. Sorry, trump is a no tax payin pile of shiit. My young wife decided to play the field and had moved several dudes into my house
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Thanks for the ramshot list, too. I will print it and put in next to the other one.
Regards,
Tom
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Thanks Travis -will keep it handy. I was thinking folks might the comparisons useful and your ramshot one makes it easy.
Last edited by kenjs1; 01/05/13.
When a country is well governed, poverty and a mean condition are something to be ashamed of. When a country is ill governed, riches and honors are something to be ashamed of
. Confucius
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Burn charts won't keep you safe. Just less dangerous...  Travis
Trump being classless,tasteless and clueless as usual. Sorry, trump is a no tax payin pile of shiit. My young wife decided to play the field and had moved several dudes into my house
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