A Lesson in Scope Parallax
I was trying to shoot an item at about 20 yards, and was coming up with about a .5” shot group. I can stack pellets at 40 yards. I found out the scope parallax was set for 100 yards by Nikon, because it was made for a high-powered rifle (It had no AO).
I turned up my nose at the Leapers name only to find out now that their scopes are everything an air-gunner could want.
Of course, to get the maximum error a person would have to be looking through at the edge of the exit pupil, and it can never exceed ½ the size of the objective lens. This means that if a person does not line up exactly on the scope axis for zeroing and every subsequent shot, then they will have added deviation from the parallax. The army calls it “maintaining the same sight picture”, and it is one of their four fundamentals of rifle marksmanship.
Before learning this I was under the impression that sight picture did not matter with scopes.
Here is the formula (I got this information from another forum where the person had dialogue with someone at Leupold and a professor).
.5 * OBJ Lens Diameter * (range to target – range to focus)/ range to focus
All units must be the same so some conversion is necessary.
Range to focus = parallax setting
It sucks to learn this stuff after the purchase.
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Last week I needed a laser for an “up the tree shot” as the target moved around I was able to get an accurate range. Because the laser is 1.5″ over bore (vs. 3″ for scope) I was able to paint the dot high on the target knowing that the pellet would land “at” or “just below” that mark.
Saved my ass and wiped his out.
The scope is fantastic for know ranges ~or~ the flat trajectory portion of my shot…. for me, 15yards -> 40yards. But for 12 yard and less shots I need the laser.
–edit , I completely missed the point that your scope isnt adjustable when I wrote this. D-oh! —
A laser mounted above the bore helps a lot with this.
Once I know holdover, windage isnt an issue as long as I can see the dot through the scope.
If I have to take a quick shot and dont have time to adjust parallax, using the laser helps a lot.
My laser is zeroed at 12 yards, and the laser dot always stays below the crosshair of the scope. The laser dot is not affected by the scope, so knowing where the pellet hits in relation to that laser makes windage error a non-issue.
If you have time to adjust, using the laser will allow you to set parallax easily without needing a solid rest.
Just shine laser, adjust parallax until dot doesnt move and your set.
If your laser is above the bore like mine, you get 2 fixed dead-on aiming points that dont change with scope adjustments.
I would like to, but Nikon said that adjusting the focus will release the seal and the waterproofing properties will be lost.
Yep. I surely did not know the calculations but, I have set my gun in a clamp
aimed at a bullseye and adjusted the parallax to be just a tad off… You can
see the crosshairs move as your eye goes from left to right… Once the
parallax is properly adjusted and the target is clear, the crosshairs stay
stationary and on target no matter where your eye is… Well to a certain
extent anyways..
I am pretty sure that you can unscrew the objective ring on your scope and
change the parallax setting to something less than 100yds…
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Perfect.
Thanks for the laser info. That makes perfect sense.