how many MOA?

Discussion in 'Long Range Hunting & Shooting' started by smoak, Mar 19, 2003.

  1. smoak

    smoak Active Member

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    Mar 16, 2003
    IF I have my 300 RUM sighted in at 100, then how many clicks should i make to have it on paper at 500? 700? 1000? By the way i have a leopold 6.5X20X50 Long Range. I am shooting a BC of .47 @ 3300 fps.
     
  2. Dave King

    Dave King Well-Known Member

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    May 3, 2001
    Smoak

    I will provide a link to the site for a free on-line calculator that can provide your answer.

    I can't give you the exact answer because you have left off some of the variables.
    http://www.eskimo.com/~jbm/ballistics/traj_basic/traj_basic.html

    You don't state the ambient temperature nor geographic altitude (I see you've stated Florida) where you will use this data.

    A short lesson in approximation:

    A standard set of come-ups that I have used for years with the 308 Win will provide a very close set of data for nearly any proper rifle. Figure the 308 Win data as a base value of 1.0 and figure the magnums and flat shooters at a value between .66 and .75.

    Yds Come-up (in MOA)
    100 -0-
    200 -2-
    300 -3-
    400 -3.5-
    500 -3.5-
    600 -4-
    700 -4.5-
    800 -5-
    900 -6-
    1000 -7-

    These are individual come-ups, you must add this together to get a total come-up in MOA. As an example, 500 yards is 2 + 3 + 3.5 + 3.5 or 12 as a total. You come-up for the 300 will be in the .66 range I'd guess... about 8 MOA of UP over your accurate 100 yard ZERO.

    To use these calculation programs correctly, you use a 100 yard zero and record the "drop" at the ranges desired. Once you have the "drop" you back-calculate the elevation requirement. For a .47 BC round at 3300fps and "STP" conditions the drop as stated (displayed by JBM) is stated as 36.8 inches. 36.8 / 5 (500 yards) is 7.36 inches, now convert this to MOA by dividing by 1.047 and you have 7.02 MOA up needed for 500 yards. (My quick rule-of-thumb 8 MOA estimate would have had you 5 inches low on the target, close enough for beginning data. )

    [ 03-20-2003: Message edited by: Dave King ]
     

  3. sscoyote

    sscoyote Well-Known Member

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    Feb 26, 2003
    Smoak, if you don't have a ballistics program you ought to get one. It sure makes the job easier, and will get you on paper quicker, and cheaper. Try Exbal by Gerald Perry. I think it's only $35, and it calculates comeup clicks for you, and it is just slick to work.
    www.perry-systems.com
     
  4. BountyHunter

    BountyHunter Writers Guild

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    Jun 13, 2007
    smoak

    Couple things.

    1. buy the ballistics calculator program.

    2. understand that 1/4 MOA is not 1/4 inch, it is .262 inches. Just like difference in yards and meters. Got to know it.

    3. Scope clicks may be in MOA, 1/4 inch or something else even thought the scope is marked 1/4 inch. Scope marked 1/4 inch have been documented as far as .282 inch.

    4. You do not know what your scope clicks really are without testing to find out.

    5. Decide what you are really asking for, Ie What are your comeups in MOA, inches,or number of actual scope clicks for your scope. All may be different. But what you want should be tied to what your scope will give you, otherwise you are converting everything.

    6. Go to Dan Lilja's website and read his article on preparing a "drop chart" and determining what your scopes click values really are.

    BH