Question about drop at distance

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  • Question about drop at distance

    Last time I was shooting longrange (for me) I was zero'd at 100 yards, shooting at 450 yards, factory hornady 123gr, comping 1.5 mils and right on target

    3.6 X 1.5 = 5.4"

    Multiply that by 4.5 (450 yards right?) and you have 24.3

    Please correct my math if I'm being stupid here

    So my 17" upper is only 24.3" low at 450 yards with a 100 yard zero??? hard to believe...

    Yes, I verified the 100 yard zero first 3 shots of the range session. I was on level ground, equal with the target's elevation. No elevated scope base or anything. Musta fired 60 rounds that day and most of them were hits.
    Last edited by Guest; 01-27-2012, 05:47 PM.

  • #2
    That is suprising, ran the factory 123gr hornady amax load through my Barnes ballistics program, and with a 200yd zero it shows me being 47.6" low at 450yds.... Something must not be right on the math?

    Comment

    • Drifter
      Chieftain
      • Mar 2011
      • 1662

      #3
      Originally posted by PaulB84 View Post
      Last time I was shooting longrange (for me) I was zero'd at 100 yards, shooting at 450 yards, factory hornady 123gr, comping 1.5 mils and right on target

      3.6 X 1.5 = 5.4"

      Multiply that by 4.5 (450 yards right?) and you have 24.3

      Please correct my math if I'm being stupid here

      So my 17" upper is only 24.3" low at 450 yards with a 100 yard zero??? hard to believe...

      Yes, I verified the 100 yard zero first 3 shots of the range session. I was on level ground, equal with the target's elevation. No elevated scope base or anything. Musta fired 60 rounds that day and most of them were hits.
      When I ran the Hornady 123gr factory load through the JBM Ballistics website, assuming a muzzle velocity ~2475 for your 17" barrel, the results at 450 yards (with 100-yard zero) were twice the numbers that you posted. Drop is calculated as 3.0 mils, or 48.8".

      If you were using holdovers in your reticle, and holding on the 3rd line, perhaps each mark represents 1 mil and not 0.5 mil as you might be thinking?

      Share more info about your scope, its reticle, its turrets, and whether you were holding over or dialing up, and maybe someone can help you figure it out.
      Drifter

      Comment


      • #4
        exactly the conclusion I came to. the scope is a falcon menace 4-14x44. heres a link showing the reticule dimensions. http://swfa.com/Falcon-Menace-4-14x4...pe-P47408.aspx

        I'll shoot the exact same spot next time I get a chance and hopefully figure it out

        Unless my Mega gator upper has a 20moa base built into it (very unlikely) I'm stumped.

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        • #5
          when aiming that high, at that distance, how far does it LOOK like to the cross hairs?

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          • #6
            Originally posted by Deezil View Post
            when aiming that high, at that distance, how far does it LOOK like to the cross hairs?
            honestly don't remember, was too happy with the bang-ding bang-ding bang-ding

            Comment

            • Drifter
              Chieftain
              • Mar 2011
              • 1662

              #7
              Originally posted by PaulB84 View Post

              Unless my Mega gator upper has a 20moa base built into it (very unlikely) I'm stumped.
              Base should be irrelevant after the scope is zeroed.

              You might be able diagnose this without actually shooting. Of course, make sure the weapon is unloaded, and pointed in a safe direction. Set the weapon up so that it will be in a solid rest, such as with a bipod and / or sandbags. (If not available, cut v-notches at each end of a cardboard box to form a makeshift rest.) Use the same 450-yard hold that you used previously, affixing it on some type of makeshift target at any distance where you can plainly see the target and reticle clearly. Dial up the elevation turret while looking through the scope, keeping the rifle solidly still during the process. As you click up, the reticle center will seemingly move down (in relation to the target). See how many clicks it takes to get the reticle center on the same target that you started with using your 450-yard holdover. Since the scope in your link indicated 0.1-mil clicks, it should take ~30 clicks... Or you can work this backwards by starting with the reticle center on the target, then dialing the turret down 30 clicks, watching the reticle move up in relation to the target, and finally making note of what part of the reticle ends up where the original center hold was on the target.
              Drifter

              Comment


              • #8
                Originally posted by Drifter View Post
                Base should be irrelevant after the scope is zeroed.

                You might be able diagnose this without actually shooting. Of course, make sure the weapon is unloaded, and pointed in a safe direction. Set the weapon up so that it will be in a solid rest, such as with a bipod and / or sandbags. (If not available, cut v-notches at each end of a cardboard box to form a makeshift rest.) Use the same 450-yard hold that you used previously, affixing it on some type of makeshift target at any distance where you can plainly see the target and reticle clearly. Dial up the elevation turret while looking through the scope, keeping the rifle solidly still during the process. As you click up, the reticle center will seemingly move down (in relation to the target). See how many clicks it takes to get the reticle center on the same target that you started with using your 450-yard holdover. Since the scope in your link indicated 0.1-mil clicks, it should take ~30 clicks... Or you can work this backwards by starting with the reticle center on the target, then dialing the turret down 30 clicks, watching the reticle move up in relation to the target, and finally making note of what part of the reticle ends up where the original center hold was on the target.
                I'm gonna get to the 100 yard range in the next couple days, and next month I'll be up north and can really push it. I plan on shooting out as far as I can find, there were a few spots pushing 1k yards that were do-able. 600-800 for sure. Will let you know my findings

                Comment

                • Drifter
                  Chieftain
                  • Mar 2011
                  • 1662

                  #9
                  My suggestion will work at any distance. If you have ~50 yards in the backyard, or even 15 yards inside the house (if your scope can reasonably focus the image and reticle at such a short distance), it's all you need to check. Should take ~30 seconds or so...
                  Drifter

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                  • #10
                    How do you know it was 450 yards?

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