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Discussion Starter #1
I picked up the Hodgdon's 2011 Annual Reloading Manual. I was looking for a chart that gave both IMR 8208XBR and Ramshot Tac.(I am working with both powders with my Socom.) I just wanted to give you an update to some of the powder range we use. This is just a general list.(#78-102)

78. IMR 3031
79. N133
80. Hodgdon Benchmark
81. H335
82. Ramshot X-terminator
83. AA 2230
84. AA 2460s
85. IMR 8208XBR
86. Ramshot Tac
87. H4895
88. N530
89. IMR 4895
90. N135
91. Alliant Reloader 12
92. AA 2495BR
93. IMR 4064
94.Norma 202
95. AA 4064
96. AA 2520
97. Alliant Reloader 15
98. N140
99. Hodgdon Varget
100. IMR 4320
101. Winchester 748
102 Hodgdon BL-C(2)

Hodgdon has also updated their site to the new burn rates, so you can check them out. www.hodgdon.com/burn-rate.html

Glenn
 

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Discussion Starter #3
Thanks Glenn. Always good to get good info.

I'm still confused by Vihta Vuori's burn rate chart compared to others: http://www.vihtavuori-lapua.com/pdfs/Burning-Rate-Chart.pdf They show IMR4064 as faster than IMR4895 or VV N-135 (which is what I've been working on most recently).
It is interesting that the burn rate chart you provided states that these are approximate burn rates, for reference only, and warns not to use for load developement.

Glenn
 

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What burns me is there are 142 powders listed in the Hornady #8 book.
144 powders listed on their web site and 173 on my old list of powders???
 

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I've never seen W748 and BL-C(2) listed as slower than AA2520, IMR-4064, R15 or Varget. I personally would look at that data with very jaundiced eyes. What were they smokin'?

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Im looking at the Hornady # 8 book now and I see..
fastest to slowest,
#74 IMR 3031
#81 IMR 4895
#90 IMR 4064
#92 RL 15
#94 Hod VARGET
#95 A2520
#98 WIN 748
#100 Hod BL-C(2)

This is way different than my old list,
 

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The VV chart doesn't look too bad.....except IMR 4064 showing up faster than 4895. No, I was commenting on the top list which supposedly came from Hodgdon. I'm not sure I agree about some things on the Hornady list either. I'm not the God of Reloading and there's lots of folks more experienced than me, but either that's sloppy publishing/ proof reading or somebody who has no real clue makin' stuff up. Doesn't matter much which it is when someone gets the wrong idea.

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Discussion Starter #9
Unfortunetely there is no standardized test these companies adhere to. It would not surprize me that some of these companies "hedge their bets." That's why it is important to work up your loads.

Glenn
 

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Im looking at the Hornady # 8 book now and I see..
fastest to slowest,
#74 IMR 3031
#81 IMR 4895
#90 IMR 4064
#92 RL 15
#94 Hod VARGET
#95 A2520
#98 WIN 748
#100 Hod BL-C(2)

This is way different than my old list,
What numbers are H-4895, IMR-4320 and A-4064 on that chart?
 

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Unfortunetely there is no standardized test these companies adhere to. It would not surprize me that some of these companies "hedge their bets." That's why it is important to work up your loads.

Glenn
It's just a ranking. They don't list actual numbers or any tolerance associated with how they measure it, so we have no idea how close one powder is to the next or maybe even 5-10 slots away.
 

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From what I've been led to believe through research and conversations with informed people, burn rate charts are based on closed bomb tests. These tests burn powder in a closed device so as to eliminate environmental influences. Additionally the closed bomb test only measures the relative burn rate of the powder at the moment of ignition. Powder burn characteristics change as the powder burns and the internal pressures change which also influences the true burn rate. Therefor burn rate charts are just a generalized rule of thumb that compares the powders initial speed of ignition.

For those of us using weapons with gas ports and pistons, we need to be concerned with how the powder burns over the time of the entire burn; in other words the powder pressure curve. There is a measurement that is used to better describe the characteristics of the powder's entire burn under varying circumstances (like the real world environment) and it is called vivacity. Powder burn rate charts do not reflect vivacity, it is an entirely different value system than what the common burn rate chart represents. I am trying to find a chart that lists all the vivacity numbers and if I ever do I would bet that the numbers would show some surprising data in regards to the burn relationships between powders

There are some powder burn rate charts that now try to display the burn rates a little more accurately by breaking the powders down into columns for each manufacturer and then listing their powders in burn rate order. This then gives us a better visual of how the powders relate to each other across brands and within the same brand. Here is an example
http://www.gsgroup.co.za/burnrates.html

I called Hornady this past Friday to try to get an explanation from them about their chart being different from most others but I haven't received an answer yet. I'll post if their answer if they respond.
 

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There are some powder burn rate charts that now try to display the burn rates a little more accurately by breaking the powders down into columns for each manufacturer and then listing their powders in burn rate order. This then gives us a better visual of how the powders relate to each other across brands and within the same brand. Here is an example
http://www.gsgroup.co.za/burnrates.html
.
That is a sweet chart! I have often wondered how powders compare to other brands, realizing a 'burn rate' chart, listed in chronological order, is not as informative as it could (and should) be.
 
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