question about setting up a drop chart

Discussion in 'Long Range Scopes and Other Optics' started by mac69, Dec 16, 2007.

  1. mac69

    mac69 New Member

    Messages:
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    Joined:
    Dec 16, 2007
    HI there, i have just brought a bushnell 10x40 fixed power elite scope and i am wanting to make a drop chart out to about 600m.
    the ballistic data provided for the 308 round is
    0@200m -8.8@300m -26.3@400m -55.2@500m

    as i am new to this game can anyone give me a guide as to approx how many clicks i will need to go up on my target turrets to be within cooeee of the target if it set to 0 at 100m

    thanks
     
  2. Buffalobob

    Buffalobob Writers Guild

    Messages:
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    Jun 12, 2001
    If you would go into your profile and fill in some information such as your geographic location it would be helpful. This will then give us a clue as to what animals you hunt. It will also let us know whether you are from a country that uses meters or one that uses yards.

    Secondly, what you need to know to build the drop chart is the muzzle velocity and the ballistic coeffecient of the bullet.

    Now then while we are waiting on you, here is lesson #1

    Some scopes are adjustable in MOA and some in inches. It becomes important to know which at ranges past 500 yards. No matter what, the math is the same.

    Correcting one inch or one MOA on the elevation turret will give you a one inch change at 100 yards, a two inch change at 200 yards and a three inch change at 300 yards and a four inch change at 400 yards and a five inch (or MOA) change at 500 yards. Knowing that piece of information makes it easy to back calculate the scope turret changes for different distances.

    For example if your bullet has a drop of 20 inches at 400 yards then to calculate the turret corrections you would divide 20 by 4 and get five inches (or MOA) of turret adjustment. The reason you divide by four is that you have 4 hundred yards.

    Finally, there is the old saying that if you give a man a loaf of bread he will be back tomorrow for another, but if you give him a skill he can get his own loaf of bread. With that in mind, you should go to this link and use it frequently.

    JBM - Calculations - Trajectory

    When you provide the needed information we can help you along a little more.