Learning the Vortex Viper PST FFP 4-16×50 rifle scope
Just finished my first range visit with my new scope. The rifle is a Tikka T3 Lite SS in .308 Win. I've got the Mountain Tactical 20 MOA base. I have it mounted in 30mm Weaver Tactical 6-hole Medium rings.
This scope has really excellent detents (or clicks) on the windage and elevation knobs! And the graduation marks are easy to read. While I am still not getting the phenomenal (<.5 MOA 3 shot) groups that I was hoping for, I decided to do the "shoot the box" drill with this scope and see how well I managed to level the scope during installation. I think I did pretty darned well! I fired 12 shots (four 3 hole groups), with the first shot 3.0 mils Up above the zero (my POA for the entire drill). My second group was 2.3 mils Right. My third group was Down 3.0 mils and the last group was 2.3 mils back to the Left, completing my "box" and returning to my zero. Not all of my 3 shot groups for this drill were admirable, but I did demonstrate that the scope adjustments work as advertised. And I couldn't have gotten a more perfect vertical change in POI when I made my elevation adjustments! The bad:
I'm still scratching my head over the parallax adjustment (or AO–adjustable objective). This is the first scope that I've ever owned that has this capability, so it is new to me. And I didn't really know, for sure, what to expect. In theory, I'm supposed to be able to adjust the knob until the target comes into sharp focus. And at that point, I should be able to move my head slightly up and down and side to side (keeping the rifle completely still) and not notice any difference in the alignment of cross hairs to the target (aka no parallax error). First, there was nowhere on that knob that I could manage to bring the target into “sharp focus”! Second, while it was quite blurry on either extreme (0 and infinity), there was not much noticeable difference between about the 50 and 500 markings on the focus knob! So very seldom did I feel confident that I had eliminated parallax error. For most of my shooting, I simply trusted the distance markings on the focus knob, since I could not ascertain any difference subjectively.
Well, I started this theme–had to finish! The ugly would be the spread on my 3 shot groups. Several times I'd have 2 out-of-three shots one atop the other, but alas, the third shot would seem to always “stray from the fold”.
I'd appreciate any advise from other shooters regarding how to adjust out parallax.
Log in to reply.