Powder temperature sensitivity?

[windwalker]

I have looked and done a couple searches for a list that shows the varying degrees of sensitivity to temperature of different powders by manufacturer and not found much. Is there a list or something that is compiled somewhere??

Thanks
Windwalker

 

[338 Mollett]

I agree with dmoran ,depending on your shooting needs find a good shooting load and put it through the paces .Shoot 20 and see how it holds up. On average Hodgdon powders have tested more stable for me.

 

[wapiti25]

If you work up a HOT load in the winter/cool months don't expect it to be OK when it is 100 degrees or left sitting in the sun. I have ruined cases doing this years ago. The powder was H335 in a 308 Win.

 

[wapiti25]

The Hodgdon powders that come from ADI have had work done that makes them more temperature stable than others.

 

[expiper]

single base will have less "mood swings" with temp changes but double base will give more vel.,,and when it gets hot so do they !!! sorta like women ,,,,Roger

 

[vtmarmot]

Ramshot Tac is generally held to be less temperature sensitive than most double-base powders. However, if you've got a slow target puller at 600 yards and let one cook in the chamber for a couple of minutes, you'll be 2 feet over the target. Happened to me twice, and then I learned better. Jack it out and put in a cold one!

 

[gmorganal]

I saw a list of several powders on this forum once where someone had tested six or eight powders at different times of the year, and 8208 xbr showed the least variation of all of them. My memory tells me it was Donovan Moran that posted the info. If I'm wrong, let me know.

 

[amlevin]

I have basically two loads for my rifle. One that I developed while wearing long johns and the other while wearing t-shirt. I then just take whatever load matches my "uniform of the day" 8)

 

[windwalker]

Thanks to all for the reply's. Basically I was looking to see if someone had developed a general listing of powders. I changed a 300 RUM load from RL25 to Retumbo due to noticing some pressure issues at altitude and cold. Seems as if the Retumbo is a little more stable. Working on a load for a 7-08 now, usually try to develop in the heat, but timing this year just did not work out, just got the gun back from the smith. Typically it seems to me that if the load is ok in 100* plus temps it will be ok when it's cold. Anybody else think this holds somewhat true?
Thanks again for the insights and wisdom.

 

[kyreloader]

Thanks to all for the reply's. Basically I was looking to see if someone had developed a general listing of powders. I changed a 300 RUM load from RL25 to Retumbo due to noticing some pressure issues at altitude and cold. Seems as if the Retumbo is a little more stable. Working on a load for a 7-08 now, usually try to develop in the heat, but timing this year just did not work out, just got the gun back from the smith. Typically it seems to me that if the load is ok in 100* plus temps it will be ok when it's cold. Anybody else think this holds somewhat true?
Thanks again for the insights and wisdom.

What bullet weight will you be loading?

 

[windwalker]

I'm going to try to get a load for the 120 BT's first. Built this one for my wife and this should be ample for the coyote sized deer we get to shoot at most times. I have a fair selection of different powders and will try a few to see what I come up with. I have alot of Win 748 and 760, a good amount of RL15, 17 19, 22 and 25. But it seems Varget might be a good one to look at also and i only have a few small jugs. I will probably use the Federal 210's as I have plenty. Headed out now to put a few together and head em down range.

 

[nevadabrass]

Absolutely! There have been many tests on this subject. Many have been published and some data is contradictive but I'll give you my own personal results.

As far as brands go, here's my list from most temperamental to least:

1. Ramshot (because they are all rifle ball powders)
2. Winchester (because they are all rifle ball powders)
3. Accurate (because they are mostly rifle ball powders)
4. Alliant
5. IMR
6. VV
7. Hodgdon


As for individual powders, my list is this: (I'm not going to name each powder here, just a few of the best and worst and a few of the ones in the middle)

most temperamental to least:

H380
H414
WW748
AA2460
WW760
H335
RL25
RL22
IMR4198
AA4350
VV550
H4895
IMR4350
IMR4831
IMR7828
N165
H1000
H322
H4831ssc
N170
N133
Benchmark
Varget


Even though some of the powders listed towards the bottom of the list are great for weather insensitivity, they still exhibit a need to tweek with the charge slightly in temperature changes to maintain a certain pressure. Despite some claims by some manufacturers that their powders will shoot the same from 20 below to 120 above, no powder is perfect. Temperature changes all combustables combustion. Period. It is unavoidable no matter what "coating" you use on the powder. And all powders show markedly different characteristics once the temp gets to and above 80 degrees. Loads worked up above 80 will still work accurately as long as the temp stays above 80 degrees. But loads worked up below 80 degrees F do better shot up to around 75 degrees. Or in other words, loads worked up in cool weather hold their node for a longer temp range than loads worked up at or above 80 degrees F.

I'm not sure why 80 degrees is the unlucky number, but I have seen this be the fulcrum of load development time and time again with every brand and make of powder--especially ball powders.




nevadabrass.com | www.nevadabrass.com

 

[Milo 2.0]

You're getting good answers here, but it really depends on your application. For safety sake, wapiti is spot on, a load developed during winter, can accelerate quickly in warm weather, especially letting rounds cook in your chamber.

One must just shoot in different temps to see what's going to happen, but Density Altitude will affect your load just as much as temp, even though the two can kind of correspond with each other.
If you're a hunter, you best be on top of it, target shooting at varying distances, you'll want to know what's going to happen, if you're benchrest shooting at the same target all day, and you're allowed sighters, I don't see what a big deal it would be, heck cloud cover coming over will give a 1/2 moa change at 1k.

And for temp sensitivity, some powders go different ways, Win 748, a very sensitive powder, doesn't change much as temp rises, but when it goes down, things change fast. Most powders go the other way though, heat brings ugly pressure.

In closing, if you have a supply of powder, just load it up and shoot the varying temps, and document what it does. In todays climate, you're probably not going to find the recommended powder anyway, because it was recommended and everyone jumped on the bandwagon without doing their own legwork.

 

[windwalker]

Thanks again for all the responses, Nevadabrass- that is exactly what I was looking for. Just a general indication of different manufacturers products. I have noticed similar results with the limited numbers of powders I have tried, but there are so many that I have no experience with, so your knowledge sharing may (or may not) save me a little money ;D. Milo-2, thanks for the info on the Win748 in the .223, I have not noticed this, but will be watching for it.

Again thanks to everyone who took the time to reply. It is much appreciated.
Windwalker

 

[TroyMN]

I have basically two loads for my rifle. One that I developed while wearing long johns and the other while wearing t-shirt. I then just take whatever load matches my "uniform of the day" 8)

Do you just try to keep the same velocities? Do you drop down to a slower node? Just wanted to get an idea in powder variance. One post on the website showed little over a grain change from their winter to summer load(.308). I can not see better groups between 45.5 and 46.0 of RL15 in my .308 cold days the 46.0 are slower than the 45.5 on a hot days.
Ever heard of. Hypothetical Example---46.1 below freezing, 45.7 32-73 degrees, 45.3 above 73...??

 

[amlevin]

I have basically two loads for my rifle. One that I developed while wearing long johns and the other while wearing t-shirt. I then just take whatever load matches my "uniform of the day" 8)

Do you just try to keep the same velocities? Do you drop down to a slower node? Just wanted to get an idea in powder variance. One post on the website showed little over a grain change from their winter to summer load(.308). I can not see better groups between 45.5 and 46.0 of RL15 in my .308 cold days the 46.0 are slower than the 45.5 on a hot days.
Ever heard of. Hypothetical Example---46.1 below freezing, 45.7 32-73 degrees, 45.3 above 73...??

None of my loads are anywhere near max, even for my "high node" ones (which I prefer for everything over 100 yds). In my part of the world I can adjust for temp within a .5 gr range for the two main powders I use (CFE223 and Varget).