Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Calculating the speed of sound

Discussion in 'Rifle Country' started by Lennyjoe, May 4, 2014.

Thread Status:
Not open for further replies.
  1. Lennyjoe

    Lennyjoe Member

    Joined:
    Dec 24, 2002
    Messages:
    6,052
    Location:
    Southwestern Ohio
    All, Looking for a good online tool to calculate the speed of sound based off of elevation and temp. Anyone have any good links?

    I took the Blackout for a test run today and am extremely happy with the results. I'm cutting down my own LC 5.56 brass, using AA 1680, 208 gr Hornady HPBT bullets. As for the rifle, its a 16" DPMS 1-7 twist, carbine gas system, AAC Cyclone suppressor, Primary Arms red dot sight and Sightmark 3x magnifier.

    The photos are of the rounds down range at 25 yards to check cycling and speed. It was 85 degrees out and our elevation was 4400 ft. 11.7 gr of AA1680 went through the chrono at 1170fps. And when I got down to 10.8 gr the bolt wouldn't cycle back all of the way. Shot 11.7gr, 11.4 gr, 11.1 gr 10.8 gr.
     

    Attached Files:

  2. Lennyjoe

    Lennyjoe Member

    Joined:
    Dec 24, 2002
    Messages:
    6,052
    Location:
    Southwestern Ohio
  3. moxie

    moxie Member

    Joined:
    Dec 30, 2002
    Messages:
    3,069
    Location:
    Erath Co., TX
  4. jerkface11

    jerkface11 Member

    Joined:
    Oct 27, 2005
    Messages:
    5,498
    Location:
    Arkansas
    I use an ap called ballistic. Just tell it the temperature and air pressure and it will tell you the speed of sound and your drop at whatever range.
     
Thread Status:
Not open for further replies.

Share This Page