Powder Temp Sensitivity

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  • Seabee

    Old Timer
    Oct 9, 2011
    517
    Left marylandistan to NC
    I emailed Western Powders asking about temp sensitivity of their Ramshot line of powders and received the following reply.

    Most of our powders are not insensitive, and will show some effect at hot and cold temperatures.

    However, we test at -40F and +125F and the deviation in most cases are ca 3% to 5% at these extreme levels. Therefore most shooters do not notice much difference under normal practical hunting conditions.

    More elaboration on the subject:

    Complete temperature stability can only be achieved with tubular extruded powders designs, either with double base (NG) and/or with other coating technologies.

    Because the ballistic performance at extreme temperature is completely dependent on the specific combination, it is very difficult to quantify and qualify.

    Our standard powders perform very well at extreme temperatures, and usually pass the strict military requirements by a large margin.

    This is a subject that often fraught with misconceptions and inaccuracies.

    The term is used loosely by manufacturers without qualifying the subject, and is obviously exploited for marketing purposes and perceptions.

    The facts are:

    Although powders can be improved, it’s really only possible with advanced coating procedures and additives which increase the cost.
    A particular powder can be improved re temperature stability for certain combinations, within a certain envelope which is specific to the following three main parameters/aspects
    The caliber.
    The weight of the projectile/bullet.
    The performance level.

    If any of these parameters/aspects go beyond or outside the intended ratio/s, the results will change and the performance will sometimes be different.

    It is also very important that when a comparison is made, that all conditions re weapon i.e. components primer, case, bullet and the velocity are equal, and preferably done at the same time on the same day.
     

    PowPow

    Where's the beef?
    Nov 22, 2012
    4,713
    Howard County
    I like Western Powders. They put out a great loading manual and data as well. I am not surprised by their candor. Thanks for sharing, Seabee!
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    The other reality is few people shoot when it is -40 and when it is +125.

    For hunting, it is a pretty narrow band of temps. So the thing to do it, do your load development in the same conditions as you hunt.
     

    Melnic

    Ultimate Member
    MDS Supporter
    Dec 27, 2012
    15,362
    HoCo
    I"ve always wondered about "temp insensitivity". The reason is that there is more to say a POI change than just the powder.
    Expansion and contraction of the barrel, bullet and the density of the air are all factors that come into play are they not?
    Wouldn't you want a powder that compensates for how the other factors of temperature affect the POI change?

    Say the temperature is high, doesn't that cause the bullet to no lose velocity as much in hotter thinner air, Don't you want the powder to then slow it down?
    And don't you care about the POI change at the desired target distance, not necessarily constancy at the muzzle?



    Just wondering about all that.
     

    dist1646

    Ultimate Member
    May 1, 2012
    8,801
    Eldersburg
    I remember Tubb telling a story about having issues with his ammo at Perry one year. He placed the ammo under the A/C vent for a while and problem went away. It got me to thinking about transporting my ammo while it was in the A/C and then being out in the sun all day at a match. Now, I try to keep it in the shade for shorter matches or in a soft cooler for temp consistency.
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,928
    Socialist State of Maryland
    When I used to compete, in summer I kept my ammo in a can with ice bags. In the winter I used to put hand warmers in the can. Now these were not the Australian powders that are supposed to be resistant to temp but, if I didn't do what I did, I believe I would have lost more matches.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    50,025
    I wonder...

    When I used to compete, in summer I kept my ammo in a can with ice bags. In the winter I used to put hand warmers in the can. Now these were not the Australian powders that are supposed to be resistant to temp but, if I didn't do what I did, I believe I would have lost more matches.
    I noticed when I go up to shoot with the Hooligans, my hand loads perform differently there than they do at home(DC area). Sometimes I go there in the winter. Would that be a temperature issue or maybe an altitude issue (or, don't say it, a shooter issue...:lol2:)?
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,928
    Socialist State of Maryland
    I noticed when I go up to shoot with the Hooligans, my hand loads perform differently there than they do at home(DC area). Sometimes I go there in the winter. Would that be a temperature issue or maybe an altitude issue (or, don't say it, a shooter issue...:lol2:)?

    At the temps they shoot in the winter, you should heat your ammo in a blast furnace. :lol:
     

    j8064

    Garrett Co Hooligan #1
    Feb 23, 2008
    11,635
    Deep Creek
    At the temps they shoot in the winter, you should heat your ammo in a blast furnace. :lol:

    Now now, even -5 ain't cold enough to keep Hooligans away from the range...
    We dress warmy...

    :innocent0
     

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    Seabee

    Old Timer
    Oct 9, 2011
    517
    Left marylandistan to NC
    Is the part below "More elaboration on the subject" them or you?

    Everything after the colon is Western powder's response.
    Sensitivity is a bit overrated for us out here in the east I think. Out west, you may start a match at 35* and end it at 100+. I do a LOT and I mean a LOT od powder testing for every cartridge I have, just to find out what works best in various ways and I do it with various methods. For the most part, we wont notice it if we work our loads in similar conditions that we will hunt or compete in. I see more difference due to altitude changes than temperature in MD. I hunt in the mountains and have to work loads here in the flatlands. Western Powders has been awesome to work with and I have great respect for thei advice. They suply me data for wildcats immediately. They have a great wealth of data that is unpublished, just ask for it. There are a few powders I've had issue with as far as temp in some cartridges and wont use them. Wont get into that here. Im working with IMR Enduron powders at the moment in several cartridges. I just wanted to share what WP had said abouit. Cheers
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    50,025
    Everything after the colon is Western powder's response.
    Sensitivity is a bit overrated for us out here in the east I think. Out west, you may start a match at 35* and end it at 100+. I do a LOT and I mean a LOT od powder testing for every cartridge I have, just to find out what works best in various ways and I do it with various methods. For the most part, we wont notice it if we work our loads in similar conditions that we will hunt or compete in. I see more difference due to altitude changes than temperature in MD. I hunt in the mountains and have to work loads here in the flatlands. Western Powders has been awesome to work with and I have great respect for thei advice. They suply me data for wildcats immediately. They have a great wealth of data that is unpublished, just ask for it. There are a few powders I've had issue with as far as temp in some cartridges and wont use them. Wont get into that here. Im working with IMR Enduron powders at the moment in several cartridges. I just wanted to share what WP had said abouit. Cheers
    Thanks for that. I've been considering my problems were due to altitude. I'm just not the learned on the matter. guess I've got reading to do.
     

    bpm32

    Active Member
    Nov 26, 2010
    675
    Thanks for this, OP. It’s refreshing that Western will be so clear in their response.

    Nitroglycerin production is a huge, huge pain. You generally can’t move it around, so double base is typically made in the same place (like at the old Radford site, where Alliant—or whatever their official name is now—uses BAE NG to make double bases). The big reason why double base powders are still used so much is that they’re better for ambient temperature fluctuations than single bases. I have pistol cycling issues in the winter with single bases like Clays or N310, and have to switch to Alliant Bullseye.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    I"ve always wondered about "temp insensitivity". The reason is that there is more to say a POI change than just the powder.
    Expansion and contraction of the barrel, bullet and the density of the air are all factors that come into play are they not?
    Wouldn't you want a powder that compensates for how the other factors of temperature affect the POI change?

    Say the temperature is high, doesn't that cause the bullet to no lose velocity as much in hotter thinner air, Don't you want the powder to then slow it down?
    And don't you care about the POI change at the desired target distance, not necessarily constancy at the muzzle?



    Just wondering about all that.

    Except the problem is, when it is hot, the powder increases pressure and velocity, not decreases. So it makes everything worse.

    Same with cold, less pressure, less velocity.
     

    Seabee

    Old Timer
    Oct 9, 2011
    517
    Left marylandistan to NC
    I tested IMR-4166 today in my 7x57ai. Barnes 120 gr TSX. Temp 92. Keep in mind I shot 3 shot groups as this is just a hunting rifle but all but 1 group has ES of 6 or less and SD under 5.
    The best group numbers was ES 0 and SD 0.3 but it measured out at .990 group size and this was the max load.
     

    Uncle Duke

    Ultimate Member
    MDS Supporter
    Feb 2, 2013
    11,720
    Not Far Enough from the City
    I tested IMR-4166 today in my 7x57ai. Barnes 120 gr TSX. Temp 92. Keep in mind I shot 3 shot groups as this is just a hunting rifle but all but 1 group has ES of 6 or less and SD under 5.
    The best group numbers was ES 0 and SD 0.3 but it measured out at .990 group size and this was the max load.

    Damn! Even for 3 shots, I've never had spreads and deviations that tight. Do you attribute this to the 4166, or you have some other things going on? Ever used it in other cartridges?
     

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