Scope Sights - Different People Different Calibration?

[shroob 9]

Hello all,

 

Just got a new scope for an air rifle and was calibrating it yesterday. Somebody said, 'You're eyes are different to mine, so the results will be different' or words to that effect. So I was wondering is this true?

 

Could a situation like this occur: I aimed the scope perfectly on the target, fired and the pellet went dead centre, then a different person tried shooting and went outside the target even though they aimed perfectly on the target?

 

Or...is it the case that if the crosshairs are lined up on a target, it doesn't matter what your vision is, that's where the pellet will go?

[walshie 2,804]

Everyone's eyes are different and everyone holds the gun differently, so the POI won't be the same for 2 different people.

[Lewis Ste 245]

The pellet drop is not going to be affected by your eyes so if you worked out the holdover/under from the zero then they zeroed the rifle the milldots should still work out as the same distance if that's what your trying to do

 

I think anyway

[pianoman 3,584]

No two people have precisely the same eyesight. That's why some wear glasses and others don't. And why wearing another persons glasses that are perfectly made to their eyesight strength renders your vision out of focus!

 

Same with scopes. That's why, unless you find a fixed focus scope that suits your eyes perfectly, an Adjustable Objective scope ( i.e. one you can focus the front lens with a turn of the front ring) is the best to go for. This also compounds the reasons why we often find we are within plus or minus a degree in error of accuracy with the rangefinding marks with a riflescope. Manufacturers know we have different eyesight-focusing strength so, the lenses are set to compromise for this. Usually in about + or - 5 or 6 yards or metres.

 

The really top end, mega expensive scopes snipers use, are precision-range calibrated to get this scope-lens rangefinding accuracy bang on the range distance set by the scope's focus on it; then, have the ability to focus your eye to that range; so you have your target exactly focused at exactly the range distance it stands from you.

 

Edited to add.

 

A pin sharp sight picture comes first; then by getting the scope reticle focused on it till it super-imposes in sharp contrast on a clearly focused Field Of View. You must not focus your eye on the reticle first-then the landscape; but concentrate on the landscape and its details in fine focus first with the reticle brought completely into phaze with your eye's view through the lenses. You must be able to view your ground and all it's details with the reticle pin sharp without having to "Split" or divide your Field of View.

 

Then zeroing the scope to that Depth of Field will give you the results of a perfectly focused scope to your eye-strength.

 

What looks perfectly sharp to me, will not look so sharp to others and vice versa.

 

Hope this makes sense!

Edited July 10, 2013 by pianoman

[AR177 588]

Yes its true, the drop etc will always stay the same but your eyes, head position, cant, are all different person to person.

 

I have shot other peoples rifles and have been as much as 1 mil out from my head position to theirs.

 

Try it with your rifle.. zero it for your normal shooting position then swap over and use the opposite eye/position

Edited July 10, 2013 by AR177

[Sweeney-Todd 208]

Poor eye relief , and initial set up can cause havoc with a scope.

 

One of the most important aspects, is setting up the scope correctly on the rifle in the first place.

 

If you try to rush this stage, chances are you will always be chasing your head position, and your MPI on the target.

Great care should be taken to get the correct eye relief.

Make sure also that your scope is not canting to left or right. ( Cross hairs are square to the rifle not dropping left or right )

 

Once you think you have the scope set, after making all the necessary adjustments, lay the rifle in front of you on the ground, get down behind it prone position, close your eyes, pick up the butt and shoulder the rifle until your happy with the cheek weld and hold, now open your eyes looking through the scope, if you have got it right, you should have a nice bright and clear sight picture, the full width of the lens.

 

Repeat the exercise, if you need to tweak a bit, DO IT, don't think aww that's close enough, your shooting and enjoyment will suffer.

 

If you are really keen, most mass produced rifles have a standard length of pull, don't be afraid to play with the butt length of your rifle, to get a perfect fit in the shoulder. ( this should be done before all of the above really )

 

You can get a very good idea of your length of pull by having your arm down at your side, now bend the arm 90 degrees at the elbow, form your trigger finger as though squeezing off a shot, measure from elbow to crease in finger, that will be a good guide.

 

All of this can be found on good old Google / YouTube, and probably explained a lot better than I can do.

 

Most people are lucky, and don't have to many problems with standard off the shelf stock length, its all worth thinking about.

 

Have fun, Good luck.

Edited July 11, 2013 by Sweeney-Todd