Retumbo - Powder temp V's velocity

Discussion in 'Reloading' started by Topshot, Dec 15, 2011.

  1. Topshot

    Topshot Well-Known Member

    Messages:
    1,085
    Joined:
    Nov 3, 2008
    Has anyone got any data on the effect temperature has on Retumbo powder with regards to muzzle velocity?

    My chronograph is a bit unreliable so I am looking for some help.

    Just want to get a feel for how sensitive this powder is to changes in temperature and to what effect. Faster, slower, magnitude?

    Also any info on H1000 would be great as well.

    Thanks
     
  2. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,708
    Joined:
    Jan 21, 2008
    I have done some work with my 6.5x284 loaded with 140vld's and 59 gr of Retumbo. My Chrono tests seem to indicate a 15-25 fps velocity difference from 25F to 80F. I am not completely confident of chrono data especially when testing on a 25F day and comparing to data aquired back when it was 80F. But, this appears to correlate well when I plug my baseline data into my ballistic program and do some actual field testing at extended ranges at the actual temperatures. Bottom line is that I get pretty close when I plug temperature changes into my ballistic program. Just my experience.
     

  3. chad44

    chad44 Well-Known Member

    Messages:
    148
    Joined:
    Jan 20, 2011
    Hogden claims that any powder with extreme on it won't be effected by temp. Both those powders are labeled as extreme. I have not tested this but I've seen guys online test it by using a cooler to freeze some rounds on a hot day and their test showed no difference. It was the guy from long range pursuit tv show.
     
  4. midnightmalloy

    midnightmalloy Well-Known Member

    Messages:
    526
    Joined:
    Jun 25, 2010
    Go to longrangepursuit.com and in there tech or do it yourself section there is a test of this you can watch. Prettygood stuff.
     
  5. Topshot

    Topshot Well-Known Member

    Messages:
    1,085
    Joined:
    Nov 3, 2008
    I contacted ADI who make this stuff. This is the reply that I got below, for what it is worth.
    I do know that they test in 24 inch barrels so that may have some effect?
    My results with my rifle seem to indicate a change of 25 fps so this is within the range that they state but over a smaller temperature range.

    It is interesting to see that they start their testing at -0 degrees. Strange things happen at the freezing point of water so a step change at this temperature might also be possible?

    Looks like more testing required with my rifles.

    *************************************************************

    Thank you for your enquiry of 7/12/2011 with regard to reloading using ADI Sporting
    powders.
    ADI propellants have a built-in technology which provides superb ballistic thermal
    insensitivity. The change in velocity over the temperature range of -0°C to 50°C is
    generally less than 30 fps. Unfortunately, we have no data measured in the particular
    firearms you mention: we perform our testing using test barrels in a controlled,
    laboratory environment. The components used will also effect the ballistic thermal
    insensitivity.
    Extreme caution should be taken and loads should be worked up accordingly. Refer to
    our website at www.adi-powders.com.au or our 5th edition handloaders’ guide for more
    information, warnings and reloading safety.
    We thank you for using ADI Sporting Powders.