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Temperature Sensitivity of Various Powders

Found this on the web on how various powders are affected by the increasing or decreasing of temperature.    8)
Yes, I realize speling is a chalunge for sum of us...I am inkluded in that grup, so pleze fourgiv me. Ski-U-Mah!

Re: Temperature Sensitivity of Various Powders

Reply #1
@Stugotz

Are these charts from an article you read. I’m curious what the numbers in the unlabeled columns are. If it is an article please provide a title or link. Thanks.

Jerry

Re: Temperature Sensitivity of Various Powders

Reply #2
@Stugotz

Are these charts from an article you read. I’m curious what the numbers in the unlabeled columns are. If it is an article please provide a title or link. Thanks.

Jerry

Those figures represent the FPS increase or decrease per degree of temperature increase or decrease.
Yes, I realize speling is a chalunge for sum of us...I am inkluded in that grup, so pleze fourgiv me. Ski-U-Mah!

Re: Temperature Sensitivity of Various Powders

Reply #3
Got it. Thanks!

Where did you find the chart in the internet?

Re: Temperature Sensitivity of Various Powders

Reply #4
Got it. Thanks!

Where did you find the chart in the internet?

Unfortunately that page is no longer available.

https://ballisticxlr.com/2015/05/15/powder-temperature-sensitivity-data/
Yes, I realize speling is a chalunge for sum of us...I am inkluded in that grup, so pleze fourgiv me. Ski-U-Mah!

Re: Temperature Sensitivity of Various Powders

Reply #5
Bummer. Thanks for trying to track it down for me thought. 👍

Re: Temperature Sensitivity of Various Powders

Reply #6
Powder "sensitivity" is completely application dependant, as can be progressivity.  Everyone thinks that a "stable" powder doesn't change speed, when in fact it's constantly changing speeds to compensate.

. The real culprit is the primer anyway, with wild swings possible in output. The powder merely has to work with what it's given, or try and adapt.   It's the $0.03 part that always screws you, isn't it?
I'm a firm believer in the theory that if it bleeds, I can kill it.

Re: Temperature Sensitivity of Various Powders

Reply #7
Powder "sensitivity" is completely application dependant, as can be progressivity.  Everyone thinks that a "stable" powder doesn't change speed, when in fact it's constantly changing speeds to compensate.

. The real culprit is the primer anyway, with wild swings possible in output. The powder merely has to work with what it's given, or try and adapt.   It's the $0.03 part that always screws you, isn't it?

When most people speak of powder sensitivity they are referring to temperature sensitivity and as a match shooter who weighs almost everything including primers I find your remarks misleading.
With all controllable things equal all powders will increase or decrease velocity with the rise and fall of the ambient temperature, humidity etc. Some powders hold the extremes tighter than others, this is what people are referring to here.
As a primer sorter I'm in complete agreement the 3 cent part which is now a 6 cent part can screw the whole thing up.
Dave

Re: Temperature Sensitivity of Various Powders

Reply #8
I know what they mean, but they don't.  A "stable" powder is constantly speeding up or slowing down it's burning rate. That's the point, it compensates for the change in input energy.

Dr. Denton Bramwell has done a pile of work on this, going clear back to the Varmint Hunter magazine days. You can read a bit of his work, over on the RSI site.
https://www.shootingsoftware.com/tech.htm

I'm a firm believer in the theory that if it bleeds, I can kill it.

Re: Temperature Sensitivity of Various Powders

Reply #9
.The real culprit is the primer anyway, It's the $0.03 part that always screws you, isn't it?

When was the last time you bought primers?
Yes, I realize speling is a chalunge for sum of us...I am inkluded in that grup, so pleze fourgiv me. Ski-U-Mah!

Re: Temperature Sensitivity of Various Powders

Reply #10
I know what they mean, but they don't.  A "stable" powder is constantly speeding up or slowing down it's burning rate. That's the point, it compensates for the change in input energy.

Dr. Denton Bramwell has done a pile of work on this, going clear back to the Varmint Hunter magazine days. You can read a bit of his work, over on the RSI site.
https://www.shootingsoftware.com/tech.htm



In my mind, and I believe most other shooter’s, the term “temperature stable” refers to an observed relatively stable muzzle velocity of a powder charge over varying conditions and most specifically with varying ambient temperature. Very few shooters are trying to measure burn rate or collecting chamber pressures when assessing powder heat stability. They are collecting muzzle velocities.
 Something in the powder composition obviously has to has to change the normal burn  rate to increased powder temperature. Using the terminology that burn rate “speeds up” and “slows down” is incomplete at best, and I suspect that terminology serves to confuse the subject and  “wow” the naive.   The same stability of muzzle velocity results would be created by a powder formula that is simply not as sensitive to changes in ambient temperature relative to a temperature sensitive powder - ie the sensitivity of a stable powder to cold or heat is “buffered”.  Burn rate speeding up or slowing down is jumbo jumbo to me. Using H4350 as an example, even very stable powders show some degree of increased burn rate with an appropriate amount of increased ambient heat. To me, that says the burn rate doesn’t slow down (chamber pressure went up, MV went up -right? ; how could burn rate go down). It makes much more sense and is a less argumentative explanation to say that burn rate just didn’t increase in as linear of a response to temperature change, as it would in a temperature sensitive powder. There is a difference between true burn rate and relative burn rate. Another way of stating this point would be to say: in a stable powder burn rate goes up with heat, but not as much as with unstable powders - it’s a relative change, or a “relative” slow down not an absolute slow down as your posted wording seems to imply.  Maybe you could clarify for us what you were trying to say that I may have misinterpreted.

Re: Temperature Sensitivity of Various Powders

Reply #11
I know what they mean, but they don't.  A "stable" powder is constantly speeding up or slowing down it's burning rate. That's the point, it compensates for the change in input energy.

Dr. Denton Bramwell has done a pile of work on this, going clear back to the Varmint Hunter magazine days. You can read a bit of his work, over on the RSI site.
https://www.shootingsoftware.com/tech.htm

Always a pleasure when you make the rounds with your condescending remarks.....
Dave