Mark 4 Side Focus Adjustments?

Discussion in 'Long Range Scopes and Other Optics' started by Misfire, Nov 29, 2008.

  1. Misfire

    Misfire Well-Known Member

    Jan 3, 2005
    I have a few questions/concerns about the side focus on the Mark 4 scopes.

    I attempted to properly set the scope up earlier this week while on the range. I started out by adjusting the focus on the eye piece by backing it all the way out, (counter clockwise) pointing it at the sky and then turning it back (clockwise) a 1/4 turn at a time. I made sure to look away from the crosshairs and then look back between the adjustments. This went without a problem and I was able to easily achieve a nice, crisp black reticule. I locked it in place.

    The next thing I did was start out on the 100 yard range and "play" with the side "focus" until the parallax was gone (crosshairs didn't move when looking back and fourth) and the target was in focus. I followed the directions in the sticky at the top of the page that said the side turrets should be focused from the infinity end of the dial every time an adjustment is made. So, as I made the adjustments I always returned the focus to the infinity end and then dialed back until I was satisfied with the focus/parallax.

    I did this drill several times from each distance starting at 100 yards and ending at 500 yards. I did not reset the side focus cap but rather recorded what distance corresponded with each mark on the cap.

    I recorded my findings and I'm a bit confused by them.

    If we start at the infinity end of the dial and count the marks backward (clockwise) it would go something like this..

    Dot 1
    Dot 2
    Dot 3
    Dot 4
    Dot 5


    The part that confuses me is that half way between the Dot 2 and Dot 3 (2.5) is the focus/parallax mark for 100 and 200 yards works out for me. Dot 3 is the focus/parallax mark for 300 and 400 yards.

    Now the weird part is that I have to go all the way back to 2.5 for the focus/parallax adjustment for 500 yards.

    I repeated this many times and ended up with the same results. Is this normal? It seemes odd to me to go back to the lower yardage marker to achieve a parallax free fov at 500 yards.


    Last edited: Nov 29, 2008