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Parallax question

Printed From: OpticsTalk by SWFA, Inc.
Category: Scopes
Forum Name: Rifle Scopes
Forum Description: Centerfire long gun scopes
URL: http://www.opticstalk.com/forum_posts.asp?TID=28920
Printed Date: August/14/2018 at 04:23
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com


Topic: Parallax question
Posted By: qball
Subject: Parallax question
Date Posted: May/03/2011 at 12:12
Right now I am estimating range (for prairie dogs) and setting the parallax adjustment on my Viper accordingly.  The obvious solution is to get a good range finder ( or measure distance to the dog holes and mark them) , but until then:

1. How sensitive are the parallax settings in relation to POI
2. Does it vary by manufacturer
3. If I'm off on my range estimates, which make my parallax setting wrong, is there a big effect

Thanks



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I wouldn't be paranoid if everyone wasn't out to get me.



Replies:
Posted By: 8shots
Date Posted: May/03/2011 at 13:03
If you have sufficient time and you actually focus your scope on the prairy dog, or the bush next to it, there will be no parallax error.
If you are simply using the range numbers as printed on the parallax dial (objective bell or side dial), then  parallax error will excist if your actual target is at a different distance. The amount of error will be minimal on far distance say at 400yds and you set your parallax to 350 or 450 yds.
There are formulas to calculate this, but let me say if you miss the prairy dog it would be due to other factors and not parallax.
 
Hope this helps.


Posted By: 8shots
Date Posted: May/03/2011 at 13:11
By the way to answer your question, parallax error is a function of the diameter of the objective (front) lens. So the bigger the front lens, the more error can excist. So rather that then manufacturer determines error.
 
Of course on a scope without a parallax adjustment the error free distance is set by the manufacturer, mostly at 150 yds. So that can differ from manufaturers.
 
The maximum point of impact error on a 50mm objective lens, set at 100 yds error free can be about 2 inches at 300 yds and 3 inches at 400 yds.
 
Hope this helps.


Posted By: qball
Date Posted: May/03/2011 at 13:13
My Viper is 6.5-20X44

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I wouldn't be paranoid if everyone wasn't out to get me.


Posted By: supertool73
Date Posted: May/03/2011 at 13:23
You would be best off just adjusting the parallax without even looking at the numbers.  They can get you ball park, but you need as 8 shots said make the adjustment on the object you are shooting at.  Once you think you have it set, move your head side to side.  If the reticle stays centered on the object you have the parallax adjusted right.  If the reticle moves from side to side as you are moving it is off.  

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Lifetime warranty and excellent customer service don't mean a thing when your gun fails during a zombie attack.

"A Liberal is a person who will give away everything they don't own."


Posted By: 8shots
Date Posted: May/03/2011 at 14:06
The 44mm objective would give less parallax error then the 50mm due to the fact that your eye can move less before you loose the sight picture forcing you to be closer to the optics path center.


Posted By: qball
Date Posted: May/03/2011 at 14:06
Thanks for the response.
There is usually plenty of time to focus on P Dogs (often just the critter itself as there isn't much out there but them).  For coyotes, probably much less time to focus but a much bigger target so maybe it's a push.


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I wouldn't be paranoid if everyone wasn't out to get me.


Posted By: qball
Date Posted: May/03/2011 at 14:08
Anyone have a good quality, but not over the top expensive range finder you really like?

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I wouldn't be paranoid if everyone wasn't out to get me.


Posted By: Dyelynn
Date Posted: May/03/2011 at 14:55
Originally posted by qball qball wrote:

Anyone have a good quality, but not over the top expensive range finder you really like?
that's highly dependent on how far you want it to report reliably... there's a few threads on this in one of the other forums here...

http://www.opticstalk.com/laser-rangefinders_forum11.html


Posted By: jonoMT
Date Posted: May/03/2011 at 15:28
I find that even with a really high-quality scope you have to remember to move your head as described. At distances past 300 yards I could be off 50 yards on either side and not know the difference just judging by the image quality.

As for rangefinders, it depends how far out you want to shoot. Based on field use, I've found that I could reliably and easily range to about half the advertised maximum with both low and high-end rangefinders. Under ideal conditions, I have been able to go out as far as 1980 yards with a Swaro and 440 yards with a Nikon (40 yards past its advertised range, although maybe it could do 400 meters). In those cases, there were very clear lines of sight - either from a high point or across a drainage. To me, PD shooting would be more demanding. I've found even the Swaro can be tricky to use when hunting antelope. If I was buying one today, I'd go with the Zeiss Victory PRF. The price is much better and it's still almost as capable as the Swaro.


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Reaction time is a factor...


Posted By: qball
Date Posted: May/03/2011 at 15:52
I don't hunt big game so it would have to be capable for coyotes and smaller....probably out to 400 yds.  I rarely have to deal with obstructions here so line of sight ususally not an issue.  Thanks for the thread.

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I wouldn't be paranoid if everyone wasn't out to get me.


Posted By: supertool73
Date Posted: May/03/2011 at 16:30
I have played with this range finder quite a bit.  http://swfa.com/Nikon-7x25-Monarch-Gold-Laser1200-Rangefinder-P42407.aspx - http://swfa.com/Nikon-7x25-Monarch-Gold-Laser1200-Rangefinder-P42407.aspx   It seemed to range as good if not better than my Leica.  I was able to range to 1400 yards with this.  I could range virtually anything withing 600, even just dirt banks.  Glass is not quite as good as the Leica, but it seemed to range great.

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Lifetime warranty and excellent customer service don't mean a thing when your gun fails during a zombie attack.

"A Liberal is a person who will give away everything they don't own."



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