Is drop really drop

Discussion in 'Long Range Hunting & Shooting' started by Kaos, Nov 30, 2009.

  1. Kaos

    Kaos New Member

    Messages:
    2
    Joined:
    Nov 30, 2009
    New to the sight so this may have been asked a thousand times so sorry for repost. My question is: does drop really stay constant.

    So if I zero in my gun at 100 yards and let's say it drops 3 in at 300 yards. Is it simple enough to just site my gun 3in high at 100 and be dead on at 300? And if I wanted it to on at 500 yards I site it in 40in high?

    Just trying to get my facts straight so any input will be helpful
     
  2. NomadPilot

    NomadPilot Well-Known Member

    Messages:
    510
    Joined:
    Aug 28, 2009
    Short answer: No.

    Using your example... I ran some numbers with Remington Shoot and a basic 308.

    The drop for a 308 at 300 is 26.55", and the drop at 500 is 82.42".

    To zero your rifle at 300, you want to be 5.21" high at 100. To zero at 500, you want to be 12.65" high at 100.

    If you were to zero 26.55" high at 100 (to match the drop at 300), your zero would be something around 775.

    If you were 82.42" high at 100 (to match your drop at 500), your zero would be something past 1000 - Rem Shoot doesn't go high enough to figure it out!
     
    Last edited: Nov 30, 2009

  3. britz

    britz Well-Known Member

    Messages:
    1,217
    Joined:
    Mar 11, 2007
    well, I'll say this:

    If your rifle hits 3" low at 300 yards, than you need to move up 1 inch per hundred yards to hit your target... so you would sight in at 1" high at 100. Having said that, there are few rifles that will shoot that flat.


    It is all about angle, if you move your scope 1 inch at 100 yards your line of sight will move 2" at 200, 3" at 300, 5" at 500, 10" at 1000yards and so on. you will hear the term minute of angle lots on this sight or minutes. This term refers to roughly 1.047" for every hundred yards or close to one inch per hundred.

    If your rifle hits 75" low at 500 from the original zero that you had set you will need to adjust your scope 25 inches at 100 yards (75 inches / 5.00)
     
  4. NomadPilot

    NomadPilot Well-Known Member

    Messages:
    510
    Joined:
    Aug 28, 2009
    I know it was just a math error, but to prevent further confusion, 75" at 500 yards is ~15 MOA, not 25.
     
  5. MontanaRifleman

    MontanaRifleman Well-Known Member

    Messages:
    6,068
    Joined:
    May 21, 2008
    The "rate" of drop is fairly consistant. i.e., my 300 RUM is zeroed @ 300 yds. At 400 yds the drop is 1.7 MOA, @ 500 yds the drop is 3.5 MOA (approx doubled), @ 600 yds the drop is 5.6 MOA, @ 700 yds the drop is 7.8 MOA, @ 800 yds - 10.2 MOA.

    The difference between 300 and 400 is 1.7 MOA, the difference between 400 and 500 is 1.8 MOA, the difference between 500 and 600 is 2.1 MOA, the diff between 600 and 700 is 2.2 MOA and the diff between 700 and 800 is 2.4 MOA.

    This would be good for wagging if you're shooting at rocks, but not something to rely on for hunting.

    Mark
     
  6. britz

    britz Well-Known Member

    Messages:
    1,217
    Joined:
    Mar 11, 2007
    Thanks for the correction... sorry for the confusion --> guess I should refrain from math when tired lol!
     
  7. Kaos

    Kaos New Member

    Messages:
    2
    Joined:
    Nov 30, 2009
    So I am assuming the 2nd responce is just a good reference since it differs from Remington shoot? I appreciate the help.