Precision Shooting 1-Part 2: Optics, Data and Logic

Discussion in 'Technical Articles - Discussion' started by ADMIN, Apr 19, 2011.

  1. ADMIN

    ADMIN Administrator

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    This is a thread for discussion of the article, Precision Shooting 1-Part 2: Optics, Data and Logic, By Ward Brien. Here you can ask questions or make comments about the article.
     
  2. BillR

    BillR Well-Known Member

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    Nice, well written and easy to understand.
     

  3. mtngun

    mtngun Well-Known Member

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    mutch to digest.
    I just saved to .doc and will read soon.
    A lot of good info there during my quick scan.
     
  4. Whitesheep

    Whitesheep Well-Known Member

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    Thank you Ward for the very informative article. I am, however, still confused by the following statement you made concerning the Shadow Effect:

    If the sunlight is behind you, it will cause a .25 moa drop. If you zeroed your rifle in sunlight, and you then shoot in cloud cover or heavy overcast, the bullet’s point of impact will be low, .5 moa. This is caused by “Shadow Effect.”

    If you take away the environmental cause of a .25 MOA drop (sunlight behind), wouldn't that result in the gun shooting higher, not lower? What am I missing?

    Thanks,

    Marc
     
  5. hamr56

    hamr56 Member

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    Wow one of the best written pieces I have seen in a while! Great information, thank you for putting this together.
     
  6. Bman940

    Bman940 Well-Known Member

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    I enjoyed the article very much Ward. I had no idea about light bending.
    Always something to learn.
    Send me a PM and I can pass somethign on to you.
    Thank you for taking the time to put all this information
    together so that us hunters can understand it.
    Without a doubt I can and will read the article again and again and
    most likely learn something each time.
    Excellent job.
     
  7. ken snyder

    ken snyder Well-Known Member

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    Hello Bart at Nikon prostaff. 2 questions. There is no doubt in my mind that a A.O. is sharper than a S.F., Ive been told it is because there is less glass in them is this true. Secondly Nikon Monarchs do not have a long enough tube length to be placed comfortabley on rifles that use integral mounts. There is no concern with sharpness or quality, does Nikon have a scope for intergral mounts, The eye relief distance arqument is absolutely not valid on adjustables of any manufacturer when turned up to the higher magnifications. Looking for a scope to reccomend.
     
  8. lightwind

    lightwind Well-Known Member

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    Ward: I greatly appreciate your articles. They are clear and well written. I would like to know if there is more written about the "shadow effect." I have not been able to find other written accounts of this effect and I am interested in the details of how it comes about. Again, thank you for the excellent articles.
     
  9. Daves762

    Daves762 Well-Known Member

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    I just put a Mark 4 on my 308 and began learning how to calculate all these bit of info into one set of adjustments on my scope.

    Great article and great info. Sounds overwelming at this point because it's all new info. Hopefully once I learn to use the scope with my load data I can do most of this in my head and leave only the wind to my full attention at the time of the shot.

    Now I have to buy a chrony and get serious as there is no way I can shoot at sea level, and hunt at 8k+ feet for deer without using a quality balistics program with accurate FPS reading for my specific load.

    Thanks for the article.
     
  10. coyotemaster

    coyotemaster Active Member

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    Thanks for a well written and very informative piece! As a Coyote hunter I was aware of the temp effect on trajectory but never could figure why the gun shot a little high/low/left/right on different days different times, until I read in the article about light bending effect of scopes. A lot of my long time shooting buddies, some in their seventies have always remarked" leave it alone it will be ok when the light changes" never knew why--they just knew.
     
  11. Finster

    Finster New Member

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    Thanks for the information there was alot of info I had to save it so I can read it thoroughly later, I had no idea about light affect on scopes that could explain why sometimes im dead on at my 600 yard plate then I just have no idea where im shooting sometimes, my range is very difficult because its flater than flat stanley.
     
  12. mildot1960

    mildot1960 Well-Known Member

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    Very weldone Ward, that is a great Post indeed Sir,

    Theres a couple of things that I would like to know? One was the Wind Chart made for a differant rifle than the .308 as used in the Math Example

    And 2, Why on the wind chart where it said use half values and the full value was IE:- 4.5 the half value about it was stated as 2.0 and not 2.250 meaning 8 clicks instead of 9 because at a 1000yards that will be off 2.5" and the only reason I ask this is because the software that I am using has the wind correction feature but if I do the Math on a .308 at 1000yds that would be 10x10 devided by 11= 9.0909090MOA, But when my program does it, IT comes out 8.5 which would then place my shot 5" off, so then I cheated and adjusted the figures by instead of deviding by 11, I devided it by 11.8 and then it was closer, As wth the 700yds that works out perfect but seeing as you use the same figure to devide the 800yds I think this might be more of an issue for the very Long Range Shooters, But not for Hunters who keep the distance down to under 500yds,

    When I did the Math on 1000yds with a 20mph wind like the one on the chart my software said the L to R was 17.0 MOA but again when I did the Math it came out at 18.18 which will put me off by 11.8 inches, So what would be the correct thing to do in this situation ???? maybe change the 17.0 to 17.6 as a Rough halfway point between the Two, I dont know,

    Ward, again thanks for A Terrific Post

    John