close
Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Hunting > Long Range Hunting & Shooting

Long Range Hunting & Shooting Nightforce Optics

Reply

density altitude

LinkBack Thread Tools Display Modes
  #1  
Unread 01-04-2011, 08:27 PM
Platinum Member
 
Join Date: Feb 2008
Location: IOWA
Posts: 2,087
density altitude

Is anyone using density altitude cards for there come ups as a backup to their electronics and PDA?
Reply With Quote
  •   #2  
    Unread 05-09-2013, 06:16 PM
    Silver Member
     
    Join Date: Jun 2003
    Location: Aussie in Italy
    Posts: 425
    Re: density altitude

    Hey Trueblue, density altitude is possibly the single most important factor in exterior ballistics predictions. However unfortunately outside of aviation circles it is not widely known or understood, nor is it used by software, making it essentially pointless.

    DA gives us the effective resistance of the air on the bullet given the temperature, atmospheric pressure, altitude and humidity. Most programs must combine these factors if you enter them in, and make something similar to a DA calculation, but as a stand alone factor it could be viable replacement for the weather based variables we input.

    By all means, use a Kestrel 4000 and log DA when shooting and you will be able to determine how your load performs in different places at different times of year, at different altitudes and temperatures with more accurately than by temperature and altitude alone.
    Reply With Quote

      #3  
    Unread 05-09-2013, 10:34 PM
    Gold Member
     
    Join Date: Feb 2013
    Posts: 912
    Re: density altitude

    "300 RUM, DA3000, 10MPH"

    0400 -0002.2 -001.5 0700 -0010.0 -002.8 L1
    0410 -0002.5 -001.5 0710 -0010.3 -002.8 L1
    0420 -0002.7 -001.6 0720 -0010.6 -002.9 L1
    0430 -0002.9 -001.6 0730 -0010.8 -002.9 L1
    0440 -0003.2 -001.7 0740 -0011.1 -003.0 L1
    0450 -0003.4 -001.7 0750 -0011.4 -003.0 L1
    0460 -0003.6 -001.7 0760 -0011.7 -003.1 L1
    0470 -0003.9 -001.8 0770 -0012.0 -003.1 L1
    0480 -0004.1 -001.8 0780 -0012.3 -003.2 L1
    0490 -0004.4 -001.9 0790 -0012.6 -003.2 L1
    0500 -0004.6 -001.9 0800 -0012.9 -003.3 L1
    0510 -0004.9 -001.9 0810 -0013.2 -003.3 L1
    0520 -0005.1 -002.0 0820 -0013.6 -003.4 L1
    0530 -0005.4 -002.0 0830 -0013.9 -003.4 L1
    0540 -0005.6 -002.1 0840 -0014.2 -003.5 L1
    0550 -0005.9 -002.1 L1 0850 -0014.5 -003.5 L2
    0560 -0006.2 -002.2 L1 0860 -0014.8 -003.6 L2
    0570 -0006.4 -002.2 L1 0870 -0015.1 -003.6 L2
    0580 -0006.7 -002.2 L1 0880 -0015.5 -003.7 L2
    0590 -0006.9 -002.3 L1 0890 -0015.8 -003.7 L2
    0600 -0007.2 -002.3 L1 0900 -0016.1 -003.8 L2
    0610 -0007.5 -002.4 L1 0910 -0016.4 -003.8 L2
    0620 -0007.7 -002.4 L1 0920 -0016.8 -003.9 L2
    0630 -0008.0 -002.5 L1 0930 -0017.1 -003.9 L2
    0640 -0008.3 -002.5 L1 0940 -0017.4 -004.0 L2
    0650 -0008.6 -002.6 L1 0950 -0017.8 -004.0 L2
    0660 -0008.8 -002.6 L1 0960 -0018.1 -004.1 L2
    0670 -0009.1 -002.6 L1 0970 -0018.5 -004.1 L2
    0680 -0009.4 -002.7 L1 0980 -0018.8 -004.2 L2
    0690 -0009.7 -002.7 L1 0990 -0019.2 -004.2 L2
    1000 -0019.5 -004.3 L2

    Yes I do and here is an example. My ballistics engine allows for an input for density altitude to correspond to a specific air density. I use the Kestrel 4000 to compute density altitude. DA is easy to use and only requires one input unlike many ballistics engines that require input of baro pressure, altitude, temp and humidity. Both methods produce the same results however only the DA method requires one input.
    __________________
    Shoot CONFIDENT, Shoot SMART, Shoot STRAIGHT
    Reply With Quote
      #4  
    Unread 05-10-2013, 01:36 AM
    Silver Member
     
    Join Date: Jun 2003
    Location: Aussie in Italy
    Posts: 425
    Re: density altitude

    Good news, so what is the software you use?
    Reply With Quote
      #5  
    Unread 05-10-2013, 06:20 AM
    Gold Member
     
    Join Date: Mar 2004
    Location: Las Vegas, NV
    Posts: 610
    Re: density altitude

    I use DA. The "Shooter" app for Android uses DA as one of the inputs for calculating its solutions.

    Jeffvn
    Reply With Quote
      #6  
    Unread 05-10-2013, 06:35 AM
    Platinum Member
     
    Join Date: Jan 2005
    Location: OK
    Posts: 2,133
    Re: density altitude

    Jim, yes I print out a set of cards that range about 3000' in DA above and below the actual elevation I will be shooting at. I then confirm DA during the day with a Kestral. If you shoot an area often enough and your kestral goes down, you should have gleaned enough local knowledge to swag out a pretty good estimate of the DA based on past experience.
    Reply With Quote
    Reply

    Bookmarks

    Thread Tools
    Display Modes


    Similar Threads for: density altitude
    Thread Thread Starter Forum Replies Last Post
    Air Density and Pattern Density Broken Brow Turkey Hunting 0 06-30-2011 09:21 PM
    Air density and bullet travel houston Long Range Hunting & Shooting 5 07-08-2010 09:54 PM
    Sectional density ? ol mike The Basics, Starting Out 5 03-06-2007 10:01 PM
    Trying to decide whether or not to interface Density Altitude into TRA Michael Eichele Rifles, Bullets, Barrels & Ballistics 12 01-19-2007 09:33 PM
    Powder Density ? edge The Basics, Starting Out 2 11-18-2005 07:41 AM


    All times are GMT -5. The time now is 09:25 PM.


    Powered by vBulletin ©2000 - 2016, Jelsoft Enterprises Ltd.
    Content Management Powered by vBadvanced CMPS
    All content ©2010-2015 Long Range Hunting, LLC