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Hornady 6.5mm ELD-x Match bullets: segmented G7 BC

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  • Hornady 6.5mm ELD-x Match bullets: segmented G7 BC

    From www.hornady/com/bc they list for the 6.5 147 ELD-x Match the following G7s for different speed ranges:

    over 2512 fps .351
    2232 fps .332
    1953 fps .321

    They used the Doppler radar system to determine these more precise BCs. These are all calculated using ICAO standard conditions

    Using ballistic ae with .351 BC and starting velocity of 2600fps at 540 yards the fps drops to 1954.

    Question #1: when shooting past 540 yards, should I use .321 as my BC in the calculator? If so, how would one account for the better bullet performance (b/c of better BC) as the bullet travels from zero yards to 540 yards.

    Question #2: do any of the BC calculators have segemented BC inputs?

    Question #3: although a 6.5CM is not optimal for 1760 yard shooting, with either a 140 Eld-x match or 147 Eld-x match, how will this bullet perform past 1400 yards since it is drops subsonic or even before 1400 yards as it transitions.

    many thanks in advance for your advice


  • #2
    Originally posted by Butleroutdoors View Post
    From www.hornady/com/bc they list for the 6.5 147 ELD-x Match the following G7s for different speed ranges:

    over 2512 fps .351
    2232 fps .332
    1953 fps .321

    They used the Doppler radar system to determine these more precise BCs. These are all calculated using ICAO standard conditions

    Using ballistic ae with .351 BC and starting velocity of 2600fps at 540 yards the fps drops to 1954.

    Question #1: when shooting past 540 yards, should I use .321 as my BC in the calculator? If so, how would one account for the better bullet performance (b/c of better BC) as the bullet travels from zero yards to 540 yards.

    Question #2: do any of the BC calculators have segemented BC inputs?

    Question #3: although a 6.5CM is not optimal for 1760 yard shooting, with either a 140 Eld-x match or 147 Eld-x match, how will this bullet perform past 1400 yards since it is drops subsonic or even before 1400 yards as it transitions.

    many thanks in advance for your advice
    I do know that some ballistic calculators allow you to "step" your BC's per speed - the Applied Ballistics app is one such program that allows you to do that. If you use a Kestrel with AB, you can true your dope at longer distances using the drop scale factor (using actual dope at distance), you can not step your BC's per muzzle velocity. Essentially the same concept though. I can't speak to other ballistic programs, hopefully you get some more comments on that from other users. I have no experience with the AE ballistics program, so I can't tell you what to do there.

    I do have personal experience shooting the 140 ELDM's at distance from a 6.5 Creedmoor. The bullet shoots very well and predictably up to and at a mile. somewhere between ~1,900-2,200 yards though, the bullet starts to drop drastically and deviates from the predicted path from the ballistics software (and I mean very drastically). We noticed this when I was shooting a target at 2,200 yards during a private ELR course. The instructors theory is that the ballistic tip finally gave up at some point past a mile, causing a dramatic drop in BC.

    If you plan on shooting up to a mile with the ELD line of bullets, they will treat you just fine.

    Comment


    • #3
      Would it not be simpler just to run 3 separate profiles in the app?
      Example: 100-800 yards
      800-1200 yards
      1200- out
      Shoot it and figure at which point things go south.

      Comment


      • #4
        .351 G7 worked just peachy for us; out to 1300 yards with a starting MV of 2850

        Comment


        • #5
          I think those BC's are averaged. So with a starting velocity of 2512 fps or higher the average G7 BC over the flight path is .351 so you'll be fine using a single number and not stepping the BC's.

          Comment


          • #6
            Running 3 calcs won't work, because you're predicting the bullet with that BC off the start, so when it gets to it's actually velocity range it'll already be too low. Use the BC for your velocity range, and true it or record your dope.

            Comment


            • #7
              Originally posted by -Time- View Post
              Running 3 calcs won't work, because you're predicting the bullet with that BC off the start, so when it gets to it's actually velocity range it'll already be too low. Use the BC for your velocity range, and true it or record your dope.
              You're a genius.

              Comment


              • #8
                With handloads and verified velocity my data shows the 147 eld supersonic to 1710 yards.

                I have made consecutive hits at 1600 yards so far. I am working on stretching the distance further.

                Comment


                • #9
                  Originally posted by kthomas

                  . The instructors theory is that the ballistic tip finally gave up at some point past a mile, causing a dramatic drop in BC.
                  .
                  Really, that's all he could come up with? How much did that class cost you?

                  The reason you see the decay curve trans, beginning and then more rapidly dropping than the models, is not the bullet tips falling off, melting or just the speed of the perfectly spinning bullet having a new BC.

                  The bullet is slowing more due the stacking of lessened stability; thus really increasing the drag. Think speed wobble as the frequency stacks it feeds back into the wobble making it worse until it is a death wobble (if not corrected artificially). Of course, nobody is able to add external correction to the projectile....

                  Some shapes work a bit better than others, but it really seems nearly universally true, that once your several mils low past a well verified and tuned dope curve, you on the event horizon of that decay going south in a hurry.


                  DIY ELR Target Cam with DVR - well proven 2000m+ 2 camera, multiple monitors - link below

                  https://forum.snipershide.com/forum/...vr#post6291944
                  Last edited by Diver160651; 09-14-2017, 01:00 AM.
                  ELR DIY Target Cam tested well past 2000m
                  NOTE: images etc do not display correctly in the Tapatalk app

                  Comment


                  • #10
                    This is very interesting for me cause I was just discussing this with a couple friends of mine. I was shooting 140 ELDM at 1600 yards and it just doesn't seem like the factory load and bullet had enough velocity and weight at that distance. I was getting probably 2 mils of shift from the same POA. I did manage to hit with with my factory RPR but we were thinking of going to the heavier 147's for the longer range. I think the weight would help carry more velocity and help keep the bc higher.

                    Comment


                    • #11
                      Originally posted by Neff991 View Post
                      Snip.. I did manage to hit with with my factory RPR but we were thinking of going to the heavier 147's for the longer range. I think the weight would help carry more velocity and help keep the bc higher.
                      Just as a slight correction, weight doesnít actually affect BC or carry more velocity. Generally higher BC bullets are heavier in a given caliber because the bullets are longer, but as we can see with something like the warne flatline bullets, they have extremely high BCs and less weight. BC is what determines the air resistance, and thus how fast your velocity drops off. The only thing that weight really affects is the kinetic energy. This could be important for hearing the impact on steel at long range, but even if you took a heavier bullet with less BC, and a lighter bullet with higher BC, at a certain point the higher velocity at range of the lighter bullet will overcome the KE of the heavier bullet. Same kind of rule as a heavier bullet requiring a faster twist. While generally this would be true, the higher twist rate needed is actually because the bullet is longer. Just some food for thought.

                      Comment


                      • #12
                        Ballistic AE has a place for it, go to the bullet library and go to other at the top where you can create a custom BC based on the velocity.

                        once you do that you can go back and select it. The BC will show up as auto and provide a BC table at the top of the drop chart.

                        Comment


                        • #13
                          ^ I have ballistic AE and I never knew that, Thanks!

                          Comment


                          • #14
                            Originally posted by -Time- View Post
                            ^ I have ballistic AE and I never knew that, Thanks!
                            Not a problem, Ive had it for years and keep finding new stuff on it such as the group measurement and the impact offset for when I shoot suppressed.

                            Funny thing is that my version is actually so old that it's a hybrid between the SE and the AE. For example I have the ability to put my ballistic profile on the range finder but lack the HUD and 3D ballistic chart.

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