Temp. sensitive powders ?

Discussion in 'Reloading' started by ol mike, May 21, 2006.

  1. ol mike

    ol mike Well-Known Member

    Aug 21, 2005
    What powders are considered temp sensitive?

    I'm working on loads in florida for a couple of guns using imr 4350 and 4831 -varget and h-380,and accurate 1680.
    I'll be moving to colorado in one year how much will this affect the loads going from tropical swamp country to 5000'?
    Thanks-- Mike
  2. Hired Gun

    Hired Gun Well-Known Member

    Apr 21, 2003
    All gunpowders are temp sensitive. I would never give up on a load that is working. I may adjust slightly if I happen to work up a redline in the winter and it acts up when it's hot out. I went through all that a long time ago when Varget and a couple of other so called extreme powders came out. All I got out of that was a lighter wallet. I didn't end up using any of them.

    Other than the Varget I have had excellent results with the powders you listed. I don't think the elevation change will have that much effect.

  3. accuratebrass

    accuratebrass Active Member

    Apr 27, 2006
    I have had excellent results with IMR 4350. I also wouldn't switch unless it wasn't working.

    Going from hot to cold is not going to be a problem. The problem comes from excess pressure when you shoot a load in hotter weather than initially developed. If you were moving to Florida from CO you may have pressure problems.

    Good Luck.
  4. ol mike

    ol mike Well-Known Member

    Aug 21, 2005
    Thanks for the advice!

    I keep seeing reloader powders in my manuals but i've read they're pretty temp-sens,so i've been reluctant to try them.
    Although people seem to do real well w/them.

    I just didn't want to spend hours of reloading to get the last 10th on groups and have to have it come apart in colorado. Mike
  5. MachV

    MachV Well-Known Member

    May 31, 2001
    I like and more importantly most of my firearms like reloader powders(R15,19,22&25)I did have to tweek the loads going from 1500' to 5000' a little but they shot alright.
    The biggest thing with reloader powders(especialy R22) is to buy enough of one lot to shoot the barrel out.Lot to lot there seams to be a big difference.
    R22 was the powder that cured me from starting at top book and working up/ubbthreads/images/graemlins/shocked.gif
  6. Mysticplayer

    Mysticplayer Writers Guild

    Jul 27, 2001
    The most temp stable powders I have played with are the Hodgdon Extreme extruded powders. They seem to work very well from winter to searing summer.

    Range, dial up, shoot, hit regardless of season.

    They used to be little to no change in my loads. However, recent lots have varied a bit. Enough so that I have to adjust up to 1/2 gr even with larger cases like the RUM.

    Unless you are looking for very small groups, you will probaly not notice any difference with the Hodgdon.

    If using some older tech powders, there can be a difference of up to 200fps from very hot to very cold. That will throw your drop tables way off.

  7. BountyHunter

    BountyHunter Writers Guild

    Jun 13, 2007
    The reloader powders (particularily 220 have been prone to wide lot to lot variations and you cannot safely just switch from one lot to the other without testing.