Parallex?

Discussion in 'Competition Shooting Forum' started by Crpdeth, Mar 7, 2004.

  1. Crpdeth

    Crpdeth Active Member

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    I've been doing alot of research on long range shooting the last few years, and have always been interested in it since I was a kid...While researching scopes the word parallex arises alot and I'm not sure what it means, any help here?

    Also, I've looked at some decent Nikon scopes lately, and have noticed that while looking through them at long distances the crosshairs become almost invisible...is there a way to adjust for this? I have an old Tasco that I use for a spotting scope, and the darkness of the crosshairs can be adjusted on it by rotating the rear eyepiece, but I didn't see an adjustment for these Nikons.

    Thanks Guys.


    ~Donny
  2. 45Smashemflat

    45Smashemflat Active Member

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    Parallax is a function of the focal length of the optics you are using. It becomes apparent when you are looking through you glass and the target is in focus along with the reticle. Now, slightly shift your head around, does the reticle move around on the target? If so you are experiencing parallax. Scientifically, it because the reticle is on a different focal plane than the target.

    It is mostly an issue at longer ranges. Scopes with an adjustable objective can eliminate parallax at the chosen range by dialing it out with the adjustable objective.

    Since, if you have parallax, you can see the reticle move in relation to the target, it is easy to understand why at these longer ranges your impact will shift if your head shifts slightly while looking through the scope.

    I am unaware of a way to "darken" the reticle on any scope. Its more a function of the background it is viewed against. Sounds like it might be out of focus though.

    Point the scope at a blank back ground like a cloudy sky. Take a quick glance through the scope - make it quick! - is the reticle in focus? If not, loosen the lock ring on the eye-piece bell and then turn the eye-piece to bring it into focus. These are usually fine threads so it takes a lot of turns to make an adjustment.

    Hope this helps....
  3. Crpdeth

    Crpdeth Active Member

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    Ok great, I understand parallax (I can even spell it better) After all this time...I should have asked sooner...I can see how not knowing about this occurance could cause unaccurate groupings as well as misses at longer ranges, Thanks for the lesson.

    Regarding the "light" crosshairs I'm playing with the notion that there is another element interefering here. Which is the fact that the scope on my 25-06 has crosshairs like this* (Excuse the crude drawing at bottom of post) and the Nikons I was looking at have lines only without the dark "pointers" that I've grown accustomed to, thereby leaving the impression that visibility is less, and I suppose realisticly that it actually is less.

    Also I think you are right about the scope being out of focus, but several factors also played against me while looking through the Nikons...I was indoors pointing the scope out through a window, holding it by hand (unsteady) and had it at max zoom (24x) as well as being unfamiller with it...Maybe I'll go give it another chance.


    ~Crp

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  4. Txquadhunter

    Txquadhunter Member

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    the pic you did is known as a "heavy duplex or duplex" depending on how thick the smaller lines are. which is suited more to hunting uses, faster to get on target so to speak. the other by what you said sounds like "fine" crosshair which is used more by target shooters, which covers less of the seen target thru the scope. where the other covers more.
  5. Crpdeth

    Crpdeth Active Member

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    Okay Hunter, that makes alot of sense...Just rambling here, but the thing I like about the scope I've been using is that it has 3 points that I am tring to use for different for ranges, once again I'll include my masterpiece drawing to show where I'm hitting at 100 yrds, I finally have my 25-06 zero'd perfectly...I'm hoping that at 200-250 yards It'll be dead center.

    I guess the fine hairs dont bother me so much, but I like having some reference points for different ranges...Mil Dot scopes seem to be the way I need to go, although after playing with a simulater and researching the formulas used to get the most out of the Mil Dots, I was left a little confused, although I plan to look into these scopes a little deeper.

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  6. Txquadhunter

    Txquadhunter Member

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    Since i haven't looked thru your scope or shot your gun i can't really say. but if your sighted in @100yrds there, i'm almost willing to bet your going to be well over 200yrds in the centern of the crosshair with your 25.06. Don't get me wrong it can done to use these points as yardage marks. you can also use the both of them on the side. use the front shoulder and the rear brisket of the avg. size deer. then use your X powers as yardage (I.E 4x=100yrds, 5x=200yrds.) when you power your scope so the shoulder and brisket fits between them you'll know his yardage. (use the points on your target easiest for you) say at 5x your target is 200yrds out. but you'll need to know the dropage of your ammo to do this do.

    I'm working on doing the same steps with my 25.06. Once the weather goes right here I'm heading out to the open farm land 800acres I have access to target shoot and coyote hunt on to sharpen my skills doing it this way.
  7. Crpdeth

    Crpdeth Active Member

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    Heh Heh, I bet your right on the bullet drop, I haven't had time to play with it out that far yet. Very interesting concerning the range estimation...I've also been getting out on some open farmland over near commerce, not near as much land as your on, but it is all open...Only problem here is that its not a real good place for target practice so I have to do that at the range which is 200 yards max...I was told we were going to extend to 300 yards which would give me some good practice, as you say, for 'otys and hogs on my friends place.

    Good luck tuning in that -06, it sure is a good looker!


    ~Crp
  8. 45Smashemflat

    45Smashemflat Active Member

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    Any item in a scopes reticle can be used for range estimation. Two very key points, you need to measure first against a "known" (I like the redfield zeroing targets for this - the 1" blocks make it easy) at known yardages, and then you need to always insure your scope is at the same power everytime you use it for ranging. This is referred to as "the reticle subtends X"s at 100 yds" for instance.

    (Note - the military Mark IV Leupold is a fixed power to prevent this mistake)

    The duplex reticle is particularly useful for this. The thickness of the thick bars bars = squirrells head at 50 yds - for instance. From cross to any thick bar is ~9" at 100 yds. From thick bar to thick bar 18" at 100 yds. (Note - this is NOT true of all duplex units - your results may vary!!! Measure yourself at known yardages.)

    Mildots essentially work the same way - the subtend a milradian. Using the dots, the edges of the dots, the edges of the bars, etc and you can figure out ranges pretty easily - assuming you have a "known" dimension to measure out there. Do a web serach for "Mildot Master" its a cool slide rule device that makes using a mildot scope very easy.

    Ditto on the bullet drop for your 25-06. That round is pretty flat shooting, I think you will still be high at 200 yds. Assuming your scope is like mine, you are currently shooting about 9" high at 100 yds. Thats going to put you about 6" high at 200 if you use the cross at 200. Pull a trajectory file from the maker of your ammo - it will help yuo figure the bullet drop at those distances.
  9. Crpdeth

    Crpdeth Active Member

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    Good stuff guys, As far as the fact that my -06 will still be high at 200 yrds is o.k. and to be honest, I'm really very glad to hear it...I'm just kinda playing with it.
    I'm just tring to get a real good feel for shooting longer ranges with it, and if its in the crosshairs even at 400yrds I'll be a happy man, as long as I've discerned where I need to be at (in the scope) at feasible ranges for hogs/coyotes, and have a good feel for what range the critter is at. That said, you guys have given me more information that I can actually use, in just a few posts, than I have gleened off the internet...I suppose most sites are tring to sell ya something, or they use terms that only accomplished long range shooters understand, leaving me only understanding a part of their commentaries.


    ~Crp
  10. kaylan1

    kaylan1 New Member

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    nice lookin guillie CRP. I'll show ya mine when I get it further along. only got one leg done right now.:D
  11. Crpdeth

    Crpdeth Active Member

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    Thank you kaylan, I really enjoy making them...I guess it gets a little monotonous after the first 24 hours or so:p .... But they are well worth the effort....Are you using Shoe Goo on the threads after sewing on the netting? or is it a kit?

    ~Crp
  12. 45Smashemflat

    45Smashemflat Active Member

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    Ah, shoe goo and flame retardant - what memories those smells bring back!!!

    Women knit and crochet, snipers shread burlap for relaxation.....
  13. kaylan1

    kaylan1 New Member

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    yup shoe goo all the way.
    how right you are smash. nothing takes me to my happy place like the smell of shoe goo and shedded burlap. add the smell of the 300 yds line during rapid fire and I'm floatin:D
    Last edited: Mar 9, 2004

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