Gunpowder charts for temp sensitivity and burn rates

JTH

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Dec 15, 2012
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102
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Wisconsin
I’m looking for a good comprehensive source of data on gunpowder, showing temperature sensitivity and burn rates. I’ve seen some charts posted here in the past, and have found some by google search, but what I’ve found is missing powders that I see folks are using in load development for cartridges I’m interested in. Examples would be rl26 and vv565, among others.

Anyone aware of updated charts showing a wider range of rifle powders? Is there a better way to get this info?
 

ButterBean

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Here you go
 

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JTH

Well-Known Member
Joined
Dec 15, 2012
Messages
102
Location
Wisconsin
Here you go
Butterbean - I’m hoping you can help me understand this better, and how you would use the data. I’m new to reloading and my experience so far is limited to Varget and H4350, which I think are very stable powders. As I’m doing research on loads for a wildcat I'm in the process of building, I’m seeing powders referenced that seem to be less stable than those mentioned above, and I want to make sure I don’t create an unknown problem in winter that I end up regretting when I pull it out to practice in July.

Looking at the temp stability chart, it seems like the chart is organized by manufacturer with the faster powders on top, slower on the bottom, correct?

I think what’s making it difficult for me to get my head wrapped around is many of the powders listed don’t show the formula for temp stability. Is it an unknown? Is there a way to find this info?

How would you use the FPS / ‘F formula? Let’s say I’m looking to buy a couple different powders to start load development for a new caliber, and I want to be sure I develop something that is fast, but also capable of going from 20 ‘F when I’m doing load development, to 85 ‘F when I’m practicing in the summer, then back down to the 20-50 degree range for hunting season. How do you apply the formula, and is there a way you can use this to help identify a potential ‘no go’ situation, or is it trial and error?
 

Buster Hemlock

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Feb 26, 2019
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NC
Yes the powders on the charts arranged fast to slow as you go from top to bottom. Varget and H4350 are two of the most temp insensitive powders on the market, the formula that is in those charts is FPS gained or lost per *F gained or lost. It is a baseline to go off but you may find a slightly different number yourself as powder lots vary and once you change a component from what they found these numbers using which is not provided things could change. Use the numbers as a guideline similar to how you would approach load data, it will get you in the ballpark. What powder and wildcat are you looking at?
 

JTH

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Joined
Dec 15, 2012
Messages
102
Location
Wisconsin
Yes the powders on the charts arranged fast to slow as you go from top to bottom. Varget and H4350 are two of the most temp insensitive powders on the market, the formula that is in those charts is FPS gained or lost per *F gained or lost. It is a baseline to go off but you may find a slightly different number yourself as powder lots vary and once you change a component from what they found these numbers using which is not provided things could change. Use the numbers as a guideline similar to how you would approach load data, it will get you in the ballpark. What powder and wildcat are you looking at?
Sherman 7 Max, built on a Defiance XM action, so I can load heavier bullets out to 3.2 coal. I’ve seen a wide range of powders beings discussed for this, including N565, N570, RL23, RL26, H1000, Retumbo, H4350. Still gathering info.
 

FEENIX

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Dec 20, 2008
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15,513
Location
Great Falls, MT
I’m looking for a good comprehensive source of data on gunpowder, showing temperature sensitivity and burn rates. I’ve seen some charts posted here in the past, and have found some by google search, but what I’ve found is missing powders that I see folks are using in load development for cartridges I’m interested in. Examples would be rl26 and vv565, among others.

Anyone aware of updated charts showing a wider range of rifle powders? Is there a better way to get this info?
As far as temp sensitivity goes, Hodgdon extreme family of propellants is the closest chart I have seen https://shop.hodgdon.com/search?search_api_fulltext=Hodgdon Extreme Extruded propellants

The IMR Enduron series claims to do the same.
 

Buster Hemlock

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Feb 26, 2019
Messages
337
Location
NC
H4350 is going to be fast for the heavies in the 7 MAX. The others you listed are all solid options. The Hodgdon powders you listed Have all performed well for temp stability for me, RL23 has been very temp stable, RL26 a little less so but not bad at all. Haven't messed with 565 or 570 yet. Best thing to do is work up your charge when it's warmer out and then as it gets towards hunting season shoot and see how much velocity your losing. I don't hunt with a clean bore so a few days before going out I hit the range to foul the bore with a few shots and confirm zero and grab some chrono numbers so I know everything is good to go.
 

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