Temperature and Speed

[amlevin]

Not long ago I overheard the "Range Oracle" expounding to another shooter how a powder increased speed x.x fps for every degree over xx and decreased a like amount for every degree of temperature decrease below xx."

Just curious, but does such information exist, where a speed increase can be predicted that closely with temperature change? If so, it would appear to me that a temperature sensitivity chart would be a slam dunk. Where powder's temperature sensitivity could be listed as a "factor" or "relative number".

Yes, I know that some powders can be more temperature sensitive than others but has this ever been quantified and available anywhere outside of a Powder Mfr's. Lab?

Just curious if there's any substance to this info or should I just turn my ear-muff volume down so I don't hear stuff like this? 8) 8)

 

[CatShooter]

Not long ago I overheard the "Range Oracle" expounding to another shooter how a powder increased speed x.x fps for every degree over xx and decreased a like amount for every degree of temperature decrease below xx."

Just curious, but does such information exist, where a speed increase can be predicted that closely with temperature change? If so, it would appear to me that a temperature sensitivity chart would be a slam dunk. Where powder's temperature sensitivity could be listed as a "factor" or "relative number".

Yes, I know that some powders can be more temperature sensitive than others but has this ever been quantified and available anywhere outside of a Powder Mfr's. Lab?

Just curious if there's any substance to this info or should I just turn my ear-muff volume down so I don't hear stuff like this? 8) 8)

No.

There are to many variables, other than the temperature alone.

 

[BoydAllen]

Perhaps you should load a batch of ammo for your favorite rifle, and do a little chronograph work at different ambient temperatures throughout the year. There are many things that we can test ourselves, and if we are serious, I think that it is always better to do that rather than try to extrapolate from material provided by others, that may not be a perfect fit for our particular situations.

 

[amlevin]

Perhaps you should load a batch of ammo for your favorite rifle, and do a little chronograph work at different ambient temperatures throughout the year. There are many things that we can test ourselves, and if we are serious, I think that it is always better to do that rather than try to extrapolate from material provided by others, that may not be a perfect fit for our particular situations.

Oh, I agree with you. I was just curious if any information like this was ever published or if this was just another of the "Range Oracle's" pronouncements 8)

 

[wapiti25]

+ 1 on what Boyd said. It may not be linear at all temperatures.

 

[bigedp51]

Air Temperature Effects On Muzzle Velocity
By Gustavo F. Ruiz

http://www.longrangehunting.com/articles/ballistics-temperature-velocity-1.php

You can buy software for a Desktop or Mobile at http://www.patagoniaballistics.com/

 

[brian427cobra]

My 260Rem had a 6fps difference from 25 outside to 105 out in the hot TEXAS sun, H4350 is very temperature insensitive, I wish it's lot to lot consistency was the same.

 

[Dans40X]

Sensitive,Insensitive,Stable,Unstable . .

It's gun powder-it is ALL sensitive to temperature variations.

Ask a NASA engineer how a solid propellent reacts in 40 degree temps to a blown O ring!!
No it's not "Need Another Seven Astronauts"
It's more like "Not Absolutely Sure of Anything"

It's much easier to function in the tropics.
Check your insensitive powder velocities at -50 degrees ambient.

 

[Turbulent Turtle]

I believe the cold temperature compromised the integrety of the O-rings on the SRBs, which caused one of them to fail and spring a leak that allowed a jet of hot gas to go directly at the main fuel tank attached under the orbiter.

I do not believe the cold weather adversely affected the burning rate of the propellant in the SRBs, so I'm not sure what that horrific event has to do with the OP's question.

 

[K22]

The 1970, Speer Number 8 reloading manual, Page 106 contains a chart that shows the variation of muzzle velocity with change in powder temperature. The footnote with the chart contains a lot of qualifiers and states "this table will serve to indicate the direction and approximate magnitude of the effect of temperature change. In other words, it's not absolute.

I make no claim to the accuracy or usefulness of this table only that it was published which I believe is what the poster asked.

PS - This was my first reloading manual.

 

[jonbearman]

Mine too,I still have it in the library.