GUN Long range shooter, help out a noob

Discussion in 'On Topic' started by DrewDown, Oct 14, 2009.

  1. DrewDown

    DrewDown OT Supporter

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    I'm going on my first big game hunt on the 23rd, and I wanna get my rifle all set up. It's sighted in at 250 yards and I would like to use a ballistic calculator to get an estimate of how many clicks adjustment I need at various ranges. I'm runnin out of time!

    My buddy who is big into hunting recommended this site, www.biggameinfo.com and I also have a ballistic calculator on my iphone. But I honestly don't even know how to fill out the information.

    Here is the rundown on my rifle and the rounds I am gonna be shooting.

    .308 with 1:11 barrel twist. 22" barrel. gonna be shooting 168 gr HPBT Sierra Match King bullets.

    Scope is a Leupold Mk 4, 4.5-14x50. Mil-dot 1/4 MOA adjustment.


    [​IMG]
     
  2. DrewDown

    DrewDown OT Supporter

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    if it sounds like i have no idea what im talking about, it's because I don't. Thanks for any input.
     
  3. Paul Revere

    Paul Revere OT Supporter

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    :hs:

    no experience with long range shooting. good luck, sweet prince.
     
  4. GarandBobcat

    GarandBobcat New Member

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    I'm not a long-range expert by any stretch of the imagination...

    But using MatchKing bullets on animals? Just from an ethical standpoint, I'd suggest GameKing (supposed to have similar internal and external ballistics, IIRC, and much more reliable terminal ballistics) or some other controlled-expansion bullet design.

    If you want to know the clicks, I'd imagine you would need to know temp, humidity, muzzle velocity, ballistic coefficients, altitude, angle of shot, wind, etc.
    One of the experienced long-range guys can probably correct me.
     
  5. DrewDown

    DrewDown OT Supporter

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    Thanks! :wavey:
     
  6. Is it commercial ammo? Whose loading is it?
     
  7. Also, which program do you have on your iphone?
     
  8. DrewDown

    DrewDown OT Supporter

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    commercial, I have a few diff manufacteres. Federal Match, Black Hills and Federal Premium. I can big up some different rounds no problem. I just don't know if I'll be able to make it back to the range.
    Ballistic FTE
     
  9. This topic starts wars on SH.

    http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Main=118525&Number=1296618
     
  10. Ok, good. Ballistic is the best program for the iPhone.

    Use these as your parameters...

    Ballistic Coefficient: Just go to the loads menu and select the load. That sets everything until you get to Sighting Characteristics. Also, since you don't know the MV, just leave it set to 2650, it should be close.

    Zero Range: 250
    Sight Height: You can try measuring between your bore centerline and your scope centerline. I bet you it's between 2.8 and 3 inches though.

    Y intercept: leave at 0
    LOS angle: leave at 0

    In the Atmospheric Conditions section you can set your zero atmosphere to what it was when you zeroed. Then, set your current atmosphere to what you figure it will be when you shoot. The wind velocity and angle are just things that you can play with to see different wind drift numbers.

    For the Output Options you can again set them to what you want. The vital zone radius tells you what the min and max distances you can hold dead on are and still hit a zone of a given size.

    If you want to be clicking your scope to account for drop and drift (rather than use holdovers) then set the elevation units and windage units to MOA.
     
  11. DrewDown

    DrewDown OT Supporter

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  12. DrewDown

    DrewDown OT Supporter

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    according to Sierra's website the ballistic coefficient is .462. but when I enter it into my iphone app it shows up as "auto" yet it gives a specific number for other bullets. what gives?
     
  13. The iPhone is using a variable BC based on velocity. It's more accurate than the single number Sierra gives you.
     
  14. ChipOnShoulder

    ChipOnShoulder New Member

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    What do the "drag models" mean in Ballistic?

    I keep it at G1, but if you change it, the drop can change significantly.
     
  15. That's a good question. They're different ways of quantifying drag, I once found a document that explained it all, but I don't remember it off the top of my head.
     
  16. DrewDown

    DrewDown OT Supporter

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    Market Garden, You fuckin rock! thats for simplifyin it for me!
     
  17. Keesh

    Keesh New Member

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    I hope you aren't going to have to carry that rifle around much.
     
  18. DrewDown

    DrewDown OT Supporter

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    Its cool man. Can't be any heavier than the 60 lbs of gear I wear at work. lol. But naw, we arent trecking too far.

    Hey MG, I got another question, after I calculate the trajectory, there is one row that is red instead of black. and its also got an arrow pointing up. What does that signify?
     
  19. That's telling you what your maximum point blank range is to hit a target the size you specified.
     
  20. DrewDown

    DrewDown OT Supporter

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    Okay I see. Thanks. If I make it back to the range, what would you suggest to zero it at?
     
  21. Most people just zero at 100 yards. If you know what distance you're going to be shooting at, you might as well zero it there though. If you are using a mil-dot scope you can zero it wherever you want, and then use holdovers to make your shots.
     
  22. DrewDown

    DrewDown OT Supporter

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    know of any good places that explain holdovers?
     
  23. Just calculate the drop and windage in mils (mRad) and then look at the numbers. Say you're zeroed at 100 yards, and the drop figure for 250 yards is -.5 mrad, then you'd simply hold the crosshairs .5mrad above the target you want to hit. Just make sure your scope is set to its "mil calibrated" (for lack of a proper term) magnification if it's a second focal plane scope. If it's FFP, then it doesn't matter what the magnification is.
     
  24. yar1182

    yar1182 New Member

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    recommend you chrono your ammo through your gun so your working with accurate numbers, it makes life much easier. Then plug the info into your ballistic software and make some charts. You'll need your FPS data from the chrono, your balistic coefficient, height over bore, etc (been discussed already).

    As far as zero I like a 50 yard zero for 308. It gives you a good range where your typically about an inch low out to 30 yards, dead on at 50, inch high out to 125, dead on at 165, 1.5" low at 200, 5.5" low at 250, and 11" low at 300. You won't need to dope for distance as much, and it's a short walk out to 50 yards to check your zero on paper as opposed to a 100 yard or 200 yard hike.

    Doping and hold over is a whole novel to type in itself. On your first trip out I don't see you taking a shoot farther than 300 yards anyways.

    Again these numbers are generalizations on what I'm punching up on serria infinity based on data that not nessasarily match your ammo or equipment.
     
  25. DrewDown

    DrewDown OT Supporter

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    thanks yar, Not sure where I can get ahold of a chrono though
     

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