scope height measurement

Discussion in 'The Basics, Starting Out' started by pvanwyk, Jul 26, 2006.

  1. pvanwyk

    pvanwyk Active Member

    Messages:
    40
    Joined:
    Dec 23, 2004
    Gentleman,
    how do I go about measuring the scope height for input into a ballistics program. I have a stock standard Rem Sendero in 300 RUM, with medium Badger rings and 20MOA picatinny rail. I have doubts as to where I should measure because of the 20MOA incline on the rail. From what I can see on the ballistics charts there seems to be a very small effect when changing scope height in a ballistic table. Can one make an assumution on the scope height i.e. 1.77" and will this still be accurate out to distances of 750yds if you're off by 0.2" ?
     
  2. Guest

    Guest Guest

    Good question. Here's how I do it. Scope Pre cant (20 MOA) is invariant to the measurement. The gun is my latest toy from Kirby. It's a mdl 700 .308 with a Holland QD brake, trigger job and scope rail holes bored out to #8. I added the Loopie 3.5-10x50 VX-III and the stoney point target nobs. Not shown in the pic is the muley pod. Last weekend it was shooting bugholes from the Harris bi-pod with my non-fire-formed brass doing load development. Everyone should own a .308

    Because of a bug in the forums software, I had to create the page on HERE on my site. The experts will likely have a more accurate approach and a faster approach - but this is fast, easy and accurate enough that any error is pure noise. (Note the rough guesstimate error is pure noise).
     

  3. LRHWAL

    LRHWAL Well-Known Member

    Messages:
    422
    Joined:
    Jan 11, 2006
    Scoops,

    I heard about your new rifle on Saturday at a 3-Gun shoot of all places (some of us here do those things too).

    Off the topic, but congratulations on your new acquisition. I look forward to taking a look at your new toy.

    Wim
     
  4. pvanwyk

    pvanwyk Active Member

    Messages:
    40
    Joined:
    Dec 23, 2004
    B1G_BORE,
    you're the man. Excellent, couldn't have asked for better. You're right about the 308. Have just got mine back after a rebuild. Pac-Nor match barrel (that's all that's available in South Africa), McMillan A5 tactical stock, 700 action, and once again Badger rail and mounts. Scope is IOR 4-14 x 50. Looking forward to the weekend to see how it performs.

    Howzit Wim, you have to come along and play some time. First group fired from my 300RUM after sighting in measured out under 1/2 MOA. Looking forward to my hunting trip next weekend. Not sure if the Springbuck are though /ubbthreads/images/graemlins/grin.gif
     
  5. overbore

    overbore Well-Known Member

    Messages:
    308
    Joined:
    Oct 14, 2004
    2scoops: I have been swapping scopes almost daily on new rifles and use this procedure: 1/2 scope diameter, plus ring height to bottom of scope, plus base thickness. To these, I run a coated rod down the bore then measure with dial calipers from center line of rod up to the bottom of the base allowing for slight sag in magazine well. This is the meaurement I enter into my Pesja ballistics program and it works out accurately to be within 0.10" at 100 yds on paper. /ubbthreads/images/graemlins/cool.gif Overbore
     
  6. D.P.

    D.P. Well-Known Member

    Messages:
    225
    Joined:
    May 21, 2004
    2scoops
    Give Badger a call I believe med badger rings on a badger rail and 700 action are 2.013"
     
  7. Ridge Runner

    Ridge Runner Well-Known Member

    Messages:
    987
    Joined:
    Dec 13, 2002
    use calipers to take 3 measurments
    1) from top edge of scope to lower edge of barrel
    2) diameter of objective where you took measurement #1
    3) diameter of barrel where you took measurement #1
    Now add measurements 2 and 3, take 1/2 of the total off of measurement #1 this is your sight heigth measurement for your ballistic program.
    RR