I recently mounted an RTS2 V4 on my primary open gun; it's my 4th, all V4s. No problem with zeroing or adjustments, and the dot stays on, as designed, on all of them. Plenty of up and down adjustment; just have to remember that it's a lot more clicks at 15 or 20 yds than we're used to at 100 with rifles.
I also turn the lock screw out 1-1/2 to 2 turns before adjusting. Don't forget that the elevation screw will turn (freewheel) in both directions even if the lock screw is tightened down, since it locks the diode plate,not the elevation screw, and that can fool you into thinking you're adjusting the elevation when you're not. The windage screw will turn (in one direction), but it's also not changing anything unless the lock screw is turned out.