measureing pressure with chronograph help???

Discussion in 'Reloading' started by ndthwacker, Jan 12, 2013.

  1. ndthwacker

    ndthwacker Member

    Messages:
    14
    Joined:
    Oct 20, 2012
    Hi i just purchased a chronograph so i can start fine tunning my reloads for my 338 lapua. I have done some research but did not come up with what i was looking for? so i guess my simple question is how do i use my chronograph the callculate pressures. is there a a formula i can use? also i have a 26in barrle 28 with a brake? dose the brake make a differnce? i have been only reloading for a year, so i have alot to learn. i have been making my reloads relativly safe. I do have one good load that i shoot out to 700 with h1000 and 300 gr otm at .10 off the lands. But want to know my 'sd' and 'es'. and most of all what pressure im at right now.
    thanks marcus
     
  2. KRP

    KRP Well-Known Member

    Messages:
    591
    Joined:
    Dec 25, 2007
    Chronographs measure speed not pressure. A lot of chronographs will calculate standard deviation and extreme spread for you, if not the formulas are readily available online.
     

  3. ndthwacker

    ndthwacker Member

    Messages:
    14
    Joined:
    Oct 20, 2012
    Thanks KRP, I know that they meassure speed but i also thought there was a formula u can get a fairly close pressure estimate from the speeds you are putting out? i could be totally wrong but i thought u can do it? if u cant how do i get my pressures without going by pressure signs alone?
     
  4. KRP

    KRP Well-Known Member

    Messages:
    591
    Joined:
    Dec 25, 2007
    You can get the equipment to measure pressure, it isn't going to be cheap though. No good way I know of to guess pressure, you'll need to monitor signs of over pressuring with your components regardless of velocity.