Scope Adjustment

Discussion in 'General Discussion' started by rick523, Oct 22, 2012.

  1. rick523

    rick523 Well-Known Member

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    I'm curious about dialing for yardage, I am just getting into the long range game and am not sure of something. I have a custom built 7mm rem mag. I am shooting 168 vld bergers(hunting type). Here is my question the rifle shoots under a half moa out to 800yds. all the range I have right now, I picked up some 140vlds again hunting to try. My 168 are loaded with 68.5 grs. H1000,hornady cases, CCI250 primers. The 140s are loaded with 69grs H1000 same case, fed match primers. the 140's are hitting exactly 1/2" higher at 100 yds than the 168s when I do my drop chart for the 140s can I just take off .5moa from what the program tells me to dial instead of changeing the sight in distance or the corrected velocity validation. I am using xbal from nightforce? Okay now for you guys that I know are going to ask for rifle specs.(lol) here they are.

    7mm rem mag
    26" krieger barrel 1-10 twist, #10 contour, 10 flutes, stainless.
    H S Precision tactical stock, green w/black webbing.
    Rem. 700 action completley reworked and accurized.
    Jewel trigger set at 1#4oz.
    Nightforce scope 5.5-22 with moar reticle, Nightforce rings and bases.
    Rifle was built by Jay Cutright,CutrightPrecision Rifles. It shoots very well like I said under half moa out to 800yds and on good days I have shot under 1/4moa out to 600 could probably do a little better but thats all my 63 year old eyes will give me. Any help will be greatly appreciated. Thanks,
    I would post a pic of rifle if I could figure that out.

    Rick,
     
  2. JackinSD

    JackinSD Well-Known Member

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    Quick answer is no.

    I doubt that the 140 and the 168 are leaving the barrel at the same speed and have the same BC's.
     

  3. rick523

    rick523 Well-Known Member

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    No they aren't I know that, I can program that in like I said the 140 are 1/2" high at 100 vs the 168's I know I could keep moving back till the 140's print dead on then use that info but seems like waste of ammo if I can use 100 yds for sight in yardage then use .5 moa less than program calls for when dialing up I would have tried it today when I was shooting but it decided to pour down rain before I got the chance.
     
  4. JackinSD

    JackinSD Well-Known Member

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    I maybe answering the wrong question here but......

    Why not just change your zero to .5" high at 100 and the program would give you the correct drop chart instead of just subtracting .5 from your drop chart?

    Maybe exbal doesn't have that option, I don't use it.

    I assume you also know the accurate fps you are getting, as you say you can program that in?

    Like I said, maybe answering the wrong question. But, having a hard time making heads or tails of your phrasing of it. Sorry.
     
  5. Joe King

    Joe King Well-Known Member

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    I don't think it's gonna work for you. The 140's have probably a 200fps muzzle velocity advantage, and that's going to cause discrepancy, add in the 140 have a zero 0.5" higher at a 100 it gets even worse on the order of 1.6MOA at 800yrds being the biggest spread, and the 168 with catch up at about 650 anyway
     
  6. rick523

    rick523 Well-Known Member

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    ok,maybe the phrasing was not quit clear enough my bad,the mv on the 168's is 2932, on the 140's about 160fps faster. With no change to scope adjustment the 140 hits 1/2" higher than the 168's @ 100yds. I don't beleive I can put in a +.5 for the zero I think I can do a minus .5moa when I run my numbers, the reason I think this may work I was shooting @ 800yds today with the 168's I had a 1gal milk jug set up with water in it the last shot I took was with the 140's took 1 shot I thought I shot over it as I saw dirt kick up behind jug when I drove down to gather targets I looked at the jug there was a hole right below the cap dead center of the jug which I believe would equal about a half moa for that distance exbal told me to dial 17moa which I did had I dialed 16.5 I think the hit would have been centered. I hope this helps also on a 3 shot group w/ the 168's two holes were less than 1/2" apart probably luck):rolleyes: the third was 2 1/2" to left this was on paper wind was from 9:00 at 3-4 mph I didn't look at the flag at target till after third shot it was hanging straight down would have been heck of a group had I looked at it first.:D Any way hope this makes more sense.
    Rick
     
  7. Joe King

    Joe King Well-Known Member

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    you mean sezro the 140's and use your trajectory card for the 168's and just take off .5MOA when you use the 140's? It'll get you somewhat close Why not just make a dope card for the 140 on say JBM ballistics, it's not hard by any means and you would be on with no guess work at all, be cheaper and a lot more precise as well.

    JBM - Calculations - Trajectory μCard

    Click on the link correct the values that aren't true for you, hit calculate, copy it to a word document and print it out, oh and bookmark the link too.

    I entered 0.5moa high zero also that way you can just print your card and take it to the range and verify it with no other adjustment.
     
  8. rick523

    rick523 Well-Known Member

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    Joe,
    Did same thing only I used G7ballistic calculater. I was using ballistics for the 140's not the 168's, on two seperate cards. Thanks

    Rick
     
  9. Joe King

    Joe King Well-Known Member

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    that is a G7, If you click on the arrow where the bullet is listed it will scroll down a list of bullets and the 168gr vld will be just a few down:)
     
  10. SBruce

    SBruce Well-Known Member

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    The NF exbal program has a spot to input your poi at a distance and it will give you the corrected zero distance and the newly corrected drops and dopes based on that zero. That is the correct way to do it when using exbal.
    Just subtracting 1/2 MOA from your previously established dopes does not always work, because dopes are based off a specific zero distance.

    It's under "Options" then "match sight in point". Input the distance, input the positive (or negative) measured poi at that distance and hit "Calculate". Hit "OK" (pop up will close) and hit "Calculate" again............new true zero distance will calculate and new drops and dopes will appear.

    Muzzle velocity still needs to be known, as does sight height.

    Hope this answers the question. Good Luck.
     
  11. rick523

    rick523 Well-Known Member

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    Bruce,
    Thanks I could not find that on my xbal, I think everyone has the misconception I was trying to use previous 168 dopes for the 140's, I was not.What I was trying to get at is I could shoot the 168's they would hit dead on, I then shot the 140's and they were 1/2" high I was still going to use 140 dope info. But I couldn't find poa correction in the xbal program since you get no kind of info with it on how to use it, you just have to search around and try to figure it out. The info you gave me was exactly what I needed. Thank you! Yes I was using MV and sight height just couldn't find poa correction.

    Rick
     
  12. JackinSD

    JackinSD Well-Known Member

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    Glad you got there. We sure took the long route.
     
  13. rick523

    rick523 Well-Known Member

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    Amen brother,:D