Is Hornady ELD-M BC wrong in Kestrel Applied Ballistics?

Senor_barney

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    (Reposting from Bolt Action rifles forum)

    Has anyone else seen jokingly off results from there Castro Advanced ballistics when shooting Hornady ELD-M?

    I'm shooting an AI/ AX in 6.5. Creedmoor with 140gr Berger Hybrids. Getting ~2800fps in my 26inch factory barrel. I've verified my DOPE to 1K at 7.6 mils up (on that day with those variables). Headshot from target below. Two impacts at 1K (one next to orange...one just outside blue at 11 oclock)

    20220112_192327.jpg


    I've loaded up some Hornady 140 ELD-M since I cannot find Berger Hybrids anymore. My load is accurate. Getting ~2750 fps. However.....

    I just bought a Kestrel with Applied Ballistics. It was telling to dial up to roughly 8.8 mils to get to 1K with zero wind. This seemed jokingly wrong...based on my experience. And, when I went to verify...sure enough...I ignored and dialed 8.1 and I was on the square at 1K.

    Before I go waste any more rounds at any other distances going of what Kestrel says, I am curious if anyone has any first-hand wonkiness with the Kestrel 140 ELD-M. Is their drag model bunk...do I need to tweak something...anything?
    I've played with BC...but I could not reasonably adjust up the BC higher to get the Kestrel to tell me 8.1 at 1K

    I've attached pictures of my guns profile to show what Im talking about

    Screenshot_20220112-185918_Kestrel LiNK Ballistics.jpg
    20220112_190001.jpg
     

    The King

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    I have had maddeningly varying results from AB with 147 eld-m bullets in both Creedmoor and PRC variants.

    This was after doing a 100% anal-retentive type analysis.

    Radar measured velocity, dial calipers on bore height, zero verification right before shooting, multiple different military grade lasers on a target etc etc.

    The solver requires intense tuning to give a good number. I too was off by more than half a mil at 1km.
     

    Hollywood 6mm

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    My AM at the Grind the last 2 years ran 140 ELDMs at the 2020 match and we had no issues with her data lining up at all. We used the custom curve in an AB Elite kestrel.

    Double check all the settings in the Kestrel itself, not just the app and make sure something didn't transfer funny or get set wrong.
     

    AIKNOWU

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    You might try running the numbers in the Kestrel to see what your G7 BC would have to be to equal your 7.6mil result. If the calculated G7 BC is just ridiculous, then you'll know that something else is off.
    In other words, double-check with other calculators. From there, you can start evaluating other variables. You might find that your scope is off a hair per click, or your range is off by 50 yards, or you had "locked" the atmospherics at sea level and 40*F, etc.
    The 140 ELD-Ms usually have something around a .320 G7 BC, I believe.

    Oh- and make sure your zero is dead on before you go back out to distance! Can't tell you how many times I've gotten wrapped around an axle way off in the weeds about a messed up BC, only to find out that my zero was off by a good bit.
     

    AIKNOWU

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    Also, double check that you used the ELD-M profile. Your 8.8mil result lines up pretty well with the solution you might get had you accidentally used a profile for the 140 BTHP Match.
    And that scope height seems low for an AI-AX. Might measure that again. An inch will put you off a good bit at 1000yds.

    Yes, I just happen to be eating breakfast with my Kestrel in front of me. I do not know how I got to this point, but I do not believe there is any going back.
     

    ma smith

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    Op, perhaps dope your rifle at 300, 600, 900 to get dead nuts drop data with tuned MV. Then worry about BC.

    For peace of mind, maybe Make sure theres nothing funny in environmental datas.

    Powder or ammo temp in mid winter may needs to be tracked if you are in cold, etc.
     
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    S3th

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    I had to increase BC from .291 to .300 in Kestrel AB to be dead on at 1,020 yards.

    I suggest truing your velocity at 500-600 yards and BC at 1,200+
     

    Senor_barney

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    The 140 ELD-Ms usually have something around a .320 G7 BC, I believe.

    Wow, so this is kind of embarrassing. I saw this morning than Hornady lists a G7 BC of .326 on its site for the 140gr ELDM whereas @Kestrel Ballistics / Applied Ballistics had .291.

    Not sure if this means Kestrel has verified lower and does not agree with Hornady's claim...but when I manually changed the BC in Kestrel to .326 it lined up perfectly ~8.1mils with what I verified in person.

    I did not have this issue with Berger, Kestrel was pretty darn close, but I'm wondering now if there are other bullets / brands Kestrel is just way off on.

    1642090232609.png
     
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    AIKNOWU

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    You know, I seem to recall that the 140 ELD-M went through a few iterations back when it was first introduced to replace the AMAX circa 2016. I believe the BC kept creeping up; I don't remember if it was design tweaks or just more accurate measurements. If you're curious, I'm sure @Rob01 could fill you in.
    .291 does seem rather low, even for the old ELD-Ms or AMAXs. Interesting.
     

    4O6shootist

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    I just went through my AB app and looked at 30 different personalized drag models for the 140 eldm. They are arranged from old to new. The newer PIDM have avg g7 of around 305, highest was 315 i found. The older PIDMs avg 295. So it does appear that G7 has gotten better over time. Applied ballistics tracks and trues their G7 bc to tansonic speeds I believe. Horandy uses banded BC for different mach speeds. The first value given at the highest velocity is what they advertise, but is only valid to 2500fps, after that the bcs are degrading. So the second/third bands are more accurate, as that's where the bullet is spending most its time in. The lowest mach 1.75(1950fps) g7 is 310. Similar to the G7 given from a lot the newer personalized drag models observed from the applied ballistics crew. I usually use the custom curve, and add velocity until my drops line up 1200y with Berger bullets. I've found Atips from Horandy to actually be better than advertised BC but i push em hard from large cases, possibly why.
     

    Rob01

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    You know, I seem to recall that the 140 ELD-M went through a few iterations back when it was first introduced to replace the AMAX circa 2016. I believe the BC kept creeping up; I don't remember if it was design tweaks or just more accurate measurements. If you're curious, I'm sure @Rob01 could fill you in.
    .291 does seem rather low, even for the old ELD-Ms or AMAXs. Interesting.

    Not that it kept creeping up but that initially Hornady put out an 800 yard average BC for the bullet which was around .610 area if memory serves but don't quote me. After looking around that all the bullet companies were using 200 yard averages they changed it to what it is today. Not a change per se but an apples to apples BC to compare to others.
     
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    AIKNOWU

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    Not that it kept creeping up but that initially Hornady put out an 800 yard average BC for the bullet which was around .610 area if memory serves but don't quote me. After looking around that all the bullet companies were using 200 yard averages they changed it to what it is today. Not a change per se but an apples to apples BC to compare to others.

    Yeah, that sounds right. Thanks for the clarification.

    As an aside to OP- I use banded BCs whenever possible. You can't do it in a Kestrel, but in Strelok or some other programs you can. Hornady's banded BCs have proven accurate for me.
     
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    FourT6and2

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    I just went through my AB app and looked at 30 different personalized drag models for the 140 eldm. They are arranged from old to new. The newer PIDM have avg g7 of around 305, highest was 315 i found. The older PIDMs avg 295. So it does appear that G7 has gotten better over time. Applied ballistics tracks and trues their G7 bc to tansonic speeds I believe. Horandy uses banded BC for different mach speeds. The first value given at the highest velocity is what they advertise, but is only valid to 2500fps, after that the bcs are degrading. So the second/third bands are more accurate, as that's where the bullet is spending most its time in. The lowest mach 1.75(1950fps) g7 is 310. Similar to the G7 given from a lot the newer personalized drag models observed from the applied ballistics crew. I usually use the custom curve, and add velocity until my drops line up 1200y with Berger bullets. I've found Atips from Horandy to actually be better than advertised BC but i push em hard from large cases, possibly why.

    I noticed this a couple of years ago and it puzzled me because there was no real announcement or explanation. When the ELD-M first came out, I began using it and I still have that same profile in my solver (Trasol). The G7 BC I've been using with good results out to 1,000 yards is 0.312.

    That said, what you're saying is interesting. Their G7 for 2,512fps and up is 0.326, 2,232fps and up is 0.320, and 1,953fps and up is 0.310. For me (6.5CM, 26", MV of 2,834fps), that's a BC of 0.326 out to 200 yards, 0.320 for 300-400 yards, and 0.310 for 500-600 yards. But what about for 700-1,000? My velocity at 1,000 = 1,552.

    Are there ways to program this progressive BC into solvers?
     
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    4O6shootist

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    I noticed this a couple of years ago and it puzzled me because there was no real announcement or explanation. When the ELD-M first came out, I began using it and I still have that same profile in my solver (Trasol). The G7 BC I've been using with good results out to 1,000 yards is 0.312.

    That said, what you're saying is interesting. Their G7 for 2,512fps and up is 0.326, 2,232fps and up is 0.320, and 1,953fps and up is 0.310. For me (6.5CM, 26", MV of 2,834fps), that's a BC of 0.326 out to 200 yards, 0.320 for 300-400 yards, and 0.310 for 500-600 yards. But what about for 700-1,000? My velocity at 1,000 = 1,552.

    Are there ways to program this progressive BC into solvers?

    With a g7 of 325 vs 310 at 2850 3k DA. Drops are exactly the same out to 600. Fine tuning the BC becomes the variable out past that. 325 g7 on has 0.1 mil less drop out to 950y. It finally becomes 0.2 mil advantage at 1k. If you're running a banded bc to get drops to line up inside 500y, you may be doing something wrong. I know myself, I likely cannot shoot the difference in groups at say 700y with a 325 vs 310 g7 bullet, its all gonna look the same, UNLESS you actually tune your load at that distance, then you may actually see it on paper. 95% of shooters do load development inside 400y. They get something that's half to third moa at 100y, they shoot it at 400, and look a 1.8" group! This development will likely hold up out to 600-700y, maybe further. The guys that shoot 1k on a regular basis, tune their loads at 800y plus. Very few shooters have the ability or qccess to do this practically unless you have property or permission to such, and time it to not be in the wind on development days. You want to shoot your rifles best ability at given distance, develop the load at that given distance.
     

    chevy_man

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    I don't use AB because it never seems to work.

    4dof is consistently within .1 for me with Hornady bullets. Strelok is also spot on.


    I've heard a few others say they quite literally have to lie to the ab software to get realistic results.
     

    4O6shootist

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    I don't use AB because it never seems to work.

    4dof is consistently within .1 for me with Hornady bullets. Strelok is also spot on.


    I've heard a few others say they quite literally have to lie to the ab software to get realistic results.
    Agreed, if your using a known true muzzle velocity from a labradar or magneto, you have to fudge the bc to get drops to match at long distance. I run 109 bergers in my gt at 2920, to get waterline at 1100y I have to use 304g7. Using the AB custom curve, I have to run the mv at 2960 to get accurate dope.
     
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    Gohring65

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    This is the prime example of truing thru shooting. Everything is a ball park to get you close, but you have to put in some work too.
     
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    seansmd

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    Couple of things didn't see any mention of calibrating your MV at around 600y?

    What version of FW is on the kestrel? A few years back(2) the 140eld CC went from good, to bad, back to good over a few revisions. As folks mentioned change to G7 and see what it tells you.

    If you search there is a thread on the 140eldm cc