Come ups and come downs

Discussion in 'Long Range Scopes and Other Optics' started by Boyd Heaton, Apr 6, 2002.

  1. Boyd Heaton

    Boyd Heaton Well-Known Member

    Messages:
    1,071
    Joined:
    May 14, 2001
    You first have to tell us the Velocity,bullet weight,b.c. of the bullet and altitude you are at.And we can get you in the ballpark.... [​IMG]
     
  2. wesley85

    wesley85 New Member

    Messages:
    3
    Joined:
    Apr 6, 2002
    Im sorry about that i totally forgot. Im shooting a Sierra 168 gr. BTHP.

    thanks
     
  3. wesley85

    wesley85 New Member

    Messages:
    3
    Joined:
    Apr 6, 2002
    Howdy, I was wondering if someone could help me out a little. I have a rem model 700 sendero chambered in a 7mm Mag. I was wondering if someone could give me the data for comeups and comedowns for my scope. the ranges i need are 100 yds through 1000yards. And if you have the data for a 10mph wind to 30 mph ill be mighty obliged.

    thanks
     
  4. Dave King

    Dave King Well-Known Member

    Messages:
    2,362
    Joined:
    May 3, 2001
    Wesley85

    The info you're asking for is not available to us (in exact terms), you need at a minimun the velocity, bullet Ballistic Coefficient (BC), ambient temperature and elevation. With this info we can give you a computer approximation which you will need to verify at the actual ranges desired.

    Here's a thread that covers this sort of thing.
    http://www.longrangehunting.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=10&t=000004

    If you don't have a chronograph you can still get come-up data from actual firing.

    First zero the rifle to hit Point Of Aim (POA) equals Point Of Impact (POI) at 100 yards.

    Now, (use these numbers as an initial go-by) adjust the scope UP 1 minute (4 "clicks on a 1/4 MOA scope). and shoot at the 200 yard target. Record the distance above or below the EXACT POA that the bullets (group) strike the target. Adjust the initial 1 minute elevation by 1/2 the error distance (if the bullet hits high then SUBTRACT 1/2 the error amount from the 1 minute and if the bullets hit low ADD 1/2 this value to the 1 minute).

    Now that you have data for 200 yards, ADD 2 minutes of elevation ON TOP of the 200 yard adjustment. this should get you very close for 300 yards. Shoot a group and measure the error either high or low and divide by 3 for the necessary ADJUSTMENT to the current scope settings. If the scope is set on 3 minutes (inches) up and the bullets are hitting 1.5 inches high at 300 yards then take .5 minutes off the elevation setting.

    For 400 yards ADD 2 minutes to the 300 yard data and repeat the verification process but divide by 4 for the correction value.

    For 500 yards ADD 2 more minutes and verify and correct (divide by 5).

    For 600 yards ADD another 2 minutes.

    For 700 ADD another 3 minutes.

    For 800 yards ADD 3 minutes.

    For 900 ADD 3.

    For 1000 ADD another 3.

    These values when added to the previous corrected value should keep you close enough to get good data.

    (These are just best guess data on my part, I didn't use a computer program but grabbed numbers from 308 come-up data and took a percentage.)
     
  5. wesley85

    wesley85 New Member

    Messages:
    3
    Joined:
    Apr 6, 2002
    Hey i appreciate the information. Ill try it when i go to the range.
    thanks