I had an ml3 (very similar) with a larue flip to side mount and magnifier.
I found under magnification that the dot was "bean shaped". I did like to 2 moa dot.
With practice and a proper zero, 300 yards should be very obtainable. Some will say even further, but that's what I felt comfortable with.
I did find that hold overs/hold under are not as precise with the dot though. @ 300, the dot becomes 6 moa and under magnification it can become a little difficult.
For the cost, i've since upgraded to a acog.