poweder problems

Discussion in 'Long Range Hunting & Shooting' started by tmmcampbell, Aug 22, 2009.

  1. tmmcampbell

    tmmcampbell Active Member

    Dec 9, 2008
    Hi, just started reloading for a 7mm ultra. The rifle is the sendero with the barrel sent in to christenson arms to lighten it up. I loaded it up with 140 gr nos part, 92.5 gr of reloader 25. velosity was around 3370 and it shot quite well. This was at about 72 deg. day. I took the same load out and shot a 98 deg. day. There were pressure signs on all the brass and the bolt handle was sticky. It also sprayed bullets in about 6 inches.

    Is reloader 25 that temp sensitive? I am looking to try h4831. However a max load is only 88 gr. with this much space in my shell will I have problems with pressure excursions. I have been told if there are large spaces of air in the case you could have problems??

    What do you guys think? Thanks
  2. liltank

    liltank Well-Known Member

    Nov 3, 2008
    I'm kind of in the same boat as you with my rifle. I don't seem to be getting the same grouping abilities as with powders with less capacities. I have a load using H1000 that is almost compressed and shoots wonderfully. I then tried shooting RL17 and with even a ten degree temp change, the rifle is shooting erratic pressure sign changes and groupings. The nice thing is that I am getting the speeds I want. The H1000 load shoots considerably slower, but it group at .5MOA where the RL17 is currently shooting .733.

    I hope this helps.


  3. winmagman

    winmagman Well-Known Member

    Mar 13, 2003
    IMHO, its not so much the 10 or 20 degree swing but where that swing occurs. For example 40 degrees to 60 degrees will most likely have a minimal effect on your load, but for some reason 70 degrees to 90 degrees can get you into big trouble. I don't know why but it seems like once you get over 80 degrees it takes much less of a temp change to radically effect a load.

    That of coarse is a generalization, when and where the changes start to happen vary with powder type and brand.