ELD-M 130 gr real BC?

bd73

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Jan 30, 2018
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#1
A friend and I have shot the ELD-M 130 gr over several occasions and we have experienced that the BC stated by Hornady does not reflect our on results. Our data indicates a BC a lot higher than the official BC.

We shot at 975 meters (1066 yards) on ice, so the point of impact was not a hundred percent verified. Still we had to adjust our hight correction with about one MRAD (10 clicks) lower than what several ballistic calculators calculated the trajectory to be. AB and Hornadys own ballistic calculator.

I have verified the velocity with a LabRadar, so I am pretty certain that the velocity is correct.

We shoot with two different rifles, one chambered in 260rem and one in 6,5x55 SE.

Our results indicates a G1 BC between .620 and .630.

Anyone else verified a higher BC than the .554 as stated by Hornady?
 
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V-Ref

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Jul 28, 2008
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#2
What twist?

Sight in/zero height and optic tracking test would be where I'd focus, before tweaking the BC much more than 10% of Doppler/AB tested values.

Measuring impact height on target in 1st person on paper for steel vs 2nd person though a scope/spotter with a reticle on a rock face, would be another example (may not be applicable here) of a window where error could get into your ballistic "correction" technique.

Not throwing rocks, just offering my thoughts from other bullets/BC truing.

I'm looking forward to trying these bullets soon myself, I'll post up what they do out of a SAUM, and look forward to seeing the results in this thread as well.
 

bd73

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Jan 30, 2018
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#3
Tip appreciated.

One was 1:8 and the other 1:9.

Since both optics were verified at 100 and 300 meters at the same shoot-out we think we have ruled out scope issues.

My friend has also previously verified the same deviation at 500 and 800 meters. I agree that 10% off official data seems to be unlikely, but we have tried to ruled out any factor possible.

If we could have verified it on paper at 800, 1000 and 1200 meters that would be a better verification, but we don't have access to facilities to do such a verification.

We both have a velocity of around 880-884 meters per second. Yesterday, when the last shoot was it was -5 Celsius, 650 meters above sea level, 30% humidity and 930 hPa barometric pressure.
 
Nov 5, 2013
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#4
without getting into the data gathering details, id have a hard time believing the 130 eld's have a higher BC than most everyone is running with the 140 eld's
 

bd73

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#5
without getting into the data gathering details, id have a hard time believing the 130 eld's have a higher BC than most everyone is running with the 140 eld's
I don't disagree with that viewpoint, so I am trying to figure out if anyone else has similar experience or if both our data and setup is somehow off.
 
Nov 5, 2013
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#6
what was your actual dope used? with the info you gave (assuming general scope height) im getting around 8.6 mil? i know a couple of guys who have shot them but they never mentioned a much higher BC...they eventually went back to the 140s...possible ranging error? i saw similar a while back when a buddy thought he had set a steel at 650 yds and was having hell getting his dope to line up...i went out to help him and found it was actually 760 yds and he was ranging a bush instead of the target
 

Long Range 338

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#7
The BC numbers Hornady is using for the ELD bullets are not typical 200 yard BC values. If you look at your velocity (mach) and then match it with the numbers from Hornady's website for the corresponding mach numbers and distance, it should line up better. Here is the page from their website that discusses this. They recommend truing at 600 yards or further.....

https://www.hornady.com/support/ballistic-coefficient
 

bd73

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#8
what was your actual dope used? with the info you gave (assuming general scope height) im getting around 8.6 mil?
My initial dope was 9,1 mil. Scope height is 6,14 centimeter (2,48"). And corrected POA with POI I was down to 8,2/8,1 mil. Keeping in mind the impact on ice it was for some shots hard to be 100% sure of where the POI was. So based on that the BC went from about the stated .55 to .62 (G1). I sent 65 shots on that mountain wall so it was a lot of repetitions 😊.

We used two different rangefinders and we where ranging on a steep mountain side so the error margin should be within a few meters.

IMG_20180328_185239.jpg
 
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bd73

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Jan 30, 2018
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#9
The BC numbers Hornady is using for the ELD bullets are not typical 200 yard BC values.
We used the mach 2.25 BC of 0.554 G1. And even with that BC we still overperformed the actual BC. I also verified my dope with the Hornady blastic calculator, and it was consistent with the two others I used.
 

Long Range 338

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Jul 10, 2012
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#10
In your pic it looks like you are shooting uphill, is that correct? 4DOF asks for this info related to your scope at your zero range (zero angle) and at the target range (shooting angle). They address how to do this in their videos linked on the 4DOF website. If you are using the Hornady app you should use the 4DOF calculator with the custom drag model as it is radar verified data.

I have a tendency to do it first and then read the instructions. I know it sounds self explanatory to use 4DOF but it was very informative for me to watch the videos and actually follow their instructions.

I've got a buddy experiencing the same thing and he is boosting his velocity by about 100fps to get the software to line up. He has never verified his scope travel on a calibrated target - I suspect this to be the issue. If he is actually moving the reticle 1.1 mils every time he dials 1.0 that error adds up very quickly! Also I know he sighted in at about a 4 degree incline at 100 yards and hasn't made any adjustment in the software to compensate for this so I can't tell you how much difference that will make but compounding errors will add up quick.

If that doesn't true it up, somebody smarter will have to help!

Keep us informed if you figure it out. I'm here to learn myself.

https://www.hornady.com/team-hornady/ballistic-calculators/4dof-ballistic-calculator/instructions

 
Nov 5, 2013
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#12
Changing scope height to 2.48 my app is showing 8.5 with the standard BC, adjusted BC to 580 gave 8.2 mil @ 1065 yds...not sure why/where yours had the 9.1 coming in but that seems high unless I converted one of your values wrong...like Steve mentioned above, could be getting some weird winds in the mountains also
 

Long Range 338

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#13
I entered your data into the 4DOF part of the calculator and was able to get pretty close (8.3 mils @ 975m). I had to adjust the axial form factor to .9 and then added a 10 degree firing angle - I assumed you were shooting up the hill not just down in the flat at that range. For what its worth, its attached.
 

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Jun 26, 2012
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#14
Key points to remember here. Their BC is based off 59F and 29.92 inHg at 0% RH

You are shooting at much colder temps and a much different pressure. Mach 2.25 or whatever will be at a different range and a different velocity as Mach is temp dependent. Of course it won’t line up to their data. Don’t worry about what they publish. Collect your dope and true the ballistic calculator. Don’t true your dope to the calculator. Also what is their published BC at what MV from the box? If you are getting a higher MV of course the BC will better.
 

bd73

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Jan 30, 2018
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#16
In your pic it looks like you are shooting uphill, is that correct? 4DOF asks for this info related to your scope at your zero range (zero angle) and at the target range (shooting angle).
Here is what I entered in the 4DOF calculator:

Screenshot_20180330-074536.png

As you can see my dope had corrected for 9 degrees angle. I know my scope is zeroed at an official range at 100 meters and there is no angle between where I shoot and where I hit. I have not verified the tracking after it was new a year and a half ago. But my friend has a different scope so it is less likely that two quality glass is that much off.

As mentioned my real life dope was about 8,1 mrads. In the Hornady app you cannot addjust BC, but if I manipulate the velocity it would have been around 923 meters per second (3028 fps). That's 40 mps more than my dope. And that's not very likely since I have measured my velocity three times in the same temperature with a LabRadar. I wish I had brought the LabRadar at the shooting, but this was supposed to be just plinking and no scientific research 😊.

So the x factor here is still unrevealed to me!
 

bd73

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#17
Wind coming from behind causing a vortex updraft near the mountain???
The wind was from ten o'clock. But there could have been winds we did not observe. It was in the evening so it was not much wind at all.
 
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bd73

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#18
I entered your data into the 4DOF part of the calculator and was able to get pretty close (8.3 mils @ 975m). I had to adjust the axial form factor to .9 and then added a 10 degree firing angle
As you see your dope differed from mine and only difference I see is the axial form factor. Why would that be .9? The firing angle was measured with a SIG 2000 to 9 degrees.
 

bd73

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Jan 30, 2018
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#19
Key points to remember here. Their BC is based off 59F and 29.92 inHg at 0% RH

You are shooting at much colder temps and a much different pressure. Mach 2.25 or whatever will be at a different range and a different velocity as Mach is temp dependent. Of course it won’t line up to their data. Don’t worry about what they publish. Collect your dope and true the ballistic calculator. Don’t true your dope to the calculator. Also what is their published BC at what MV from the box? If you are getting a higher MV of course the BC will better.
Yes, the answer could be hidden in what you saying here. I think we got a bit blinded by the high BC number our results produced. It was as high as the ELD-M 140 gr. Of course we did not have the 140 gr bullet to compare the results with - that would have been interesting.

I am not an engineer in physics so I probably get this wrong, but I would assume that lower pressure and temperature would produced lower BC. What you saying is the opposite?

But I will stick to my new and verified dope. In May I will get a chance to shoot at steel at 1300 meters so then I will get a new verification of my dope.
 

bd73

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Jan 30, 2018
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#20
Changing scope height to 2.48 my app is showing 8.5 with the standard BC, adjusted BC to 580 gave 8.2 mil @ 1065 yds...not sure why/where yours had the 9.1 coming in but that seems high unless I converted one of your values wrong...like Steve mentioned above, could be getting some weird winds in the mountains also
I don't spot the difference in the input between our different results.

The result is reproduced four times. But all four on the same range. So it is possible it is the same type of wind making tricks with the bullets here.
 
Jun 26, 2012
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#21
Yes, the answer could be hidden in what you saying here. I think we got a bit blinded by the high BC number our results produced. It was as high as the ELD-M 140 gr. Of course we did not have the 140 gr bullet to compare the results with - that would have been interesting.

I am not an engineer in physics so I probably get this wrong, but I would assume that lower pressure and temperature would produced lower BC. What you saying is the opposite?

But I will stick to my new and verified dope. In May I will get a chance to shoot at steel at 1300 meters so then I will get a new verification of my dope.
Are these hand loads or factory ammo?
 

bd73

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#22
Are these hand loads or factory ammo?
Hand loads. 44,9 gr of Reload Swiss RS62 in a Lapua .260 case and Fed 210 GM for ignition. Over four different ten shot series chronographed with LabRadar the average ES and SD was 7,25 and 2,73 (meters per second).
 
Jun 26, 2012
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#24
Hand loads. 44,9 gr of Reload Swiss RS62 in a Lapua .260 case and Fed 210 GM for ignition. Over four different ten shot series chronographed with LabRadar the average ES and SD was 7,25 and 2,73 (meters per second).
Well there you go. With ha d loads those box numbers mean squat. U r correct colder usually means slower but it’s possible that your hand loads are still faster than their factory load even when it’s much colder.

Collect your data and drive on. Also Morgan is giving u some nuggets as well.
 

bd73

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Jan 30, 2018
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#25
Slight velocity bump and tweaking axial form factor to .9 gets really close...does this match your app with these inputs?
If I stay on the speed of 883 mps I get nearly close to your result:

Screenshot_20180330-160416.png

That is closer to reality of the dope I observed. Can you explain this axial form factor? I read what was written in the help section but I am still not sure I understand the science behind it.
 
Nov 5, 2013
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#26
basically what dillhole mentioned above...its hornady's way of bending the curve for BC/trajectory variances between different rifles/twists rates/conditions/etc

hornady data is gathered for a specific set of variables...you start getting away from those set variables and things will change, and the form factor value is the way to tweak it
 

bd73

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Jan 30, 2018
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#27
Well there you go. With ha d loads those box numbers mean squat.
Do you mean that BC is effected by the velocity of the load even when I am within the 2.25 mach? Does that mean that in reality I get a higher BC because of higher velocity than Hornady used when they made their data?

Collect your data and drive on. Also Morgan is giving u some nuggets as well.
Yes he did. That axial form factor seams to be the x in this equation. It only remains for me to understand the theory behind it.

Thanks for relevant input, guys!
 
Jun 26, 2012
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#28
Do you mean that BC is effected by the velocity of the load even when I am within the 2.25 mach? Does that mean that in reality I get a higher BC because of higher velocity than Hornady used when they made their data?



Yes he did. That axial form factor seams to be the x in this equation. It only remains for me to understand the theory behind it.

Thanks for relevant input, guys!
Mach is temp dependent. The colder it is you will get Mach 2.25 at a different velocity than they did when it was 59 and at a different distance, you will reach it further out than they did because Mach 2.25 is a lower number for you.
 

bd73

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Jan 30, 2018
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#29
basically what dillhole mentioned above...its hornady's way of bending the curve for BC/trajectory variances between different rifles/twists rates/conditions/etc

hornady data is gathered for a specific set of variables...you start getting away from those set variables and things will change, and the form factor value is the way to tweak it
I think what your saying is finally starting to sink in. Up today I have thought of the BC as a much more constant variable that it in reality is. Thank you for being patient 😁.
 
Feb 7, 2013
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#30
My initial dope was 9,1 mil. Scope height is 6,14 centimeter (2,48"). And corrected POA with POI I was down to 8,2/8,1 mil. Keeping in mind the impact on ice it was for some shots hard to be 100% sure of where the POI was. So based on that the BC went from about the stated .55 to .62 (G1). I sent 65 shots on that mountain wall so it was a lot of repetitions 😊.
The Axial thing seems like the DK,DSF, DC in the other programs that "bend the curve". The rub for most solvers is that a little can effect the curve in areas you do not want effected.
Look about 1 min in; I find it interesting that they do address what some of us questioned early on; How can doppler or a "custom curve" be click accurate in all systems, sense the yaw and engraving etc certainly would effect the built flight? Seems like they have a good thing going and have an answer for that very question; but I do not have enough time using the solver, so I am not suggesting the solution.

Regardless, of the 4DOF calculator we know that at that range G1 numbers in AB, CB, FFS, Shooter you name it are all relatively close with correct inputs, even without curve fitting much. So there seems to be a red flag in there no matter how you look at it. 1 mil off at that close range isn't something that should be happening.

Going to the end to modify the 4DOF in this case seems extreme. I'd be somewhat concerned to tweak only one thing to it max, without going back and having several points to verify the curve fit adjustment. Ideally your shoot your zero, and several point to the end game the same day under the same conditions, "if" you wanted to be completely certain all was dialed.

Keep us posed.
 
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isofahunter

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Jun 11, 2010
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#31
The axial form factor is important in getting the theoretical data to match what your rifle is actually doing. Follow the video instructions to the letter and results are good skip any part and results are marginal.
 

Long Range 338

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#32
As you see your dope differed from mine and only difference I see is the axial form factor. Why would that be .9? The firing angle was measured with a SIG 2000 to 9 degrees.
Axial Form Factor is Hornady's way of adjusting the custom drop curve (instead of changing BC value). Because the 4DOF calculator is not using BC, it allows you to customize the calculator to match your actual dope.
 

bd73

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#33
Axial Form Factor is Hornady's way of adjusting the custom drop curve (instead of changing BC value). Because the 4DOF calculator is not using BC, it allows you to customize the calculator to match your actual dope.
Thank you for explaining this in a layman's terms.
 
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#34
Axial Form Factor is Hornady's way of adjusting the custom drop curve (instead of changing BC value). Because the 4DOF calculator is not using BC, it allows you to customize the calculator to match your actual dope.
yes sure, BC aside, it is the same basic idea as DC in CB etc.. The MAX range of adjustment is .9 - he needs .9 seems sketchy - something else is contributing to this error..

@bd73 run the G1 in the non-DOF calculator inside the Hornady app.. what kind of BC tweak do you need? I'd bet the same as in every other solver and very close to the 4DOF predictions before maxing out the Axial adjustment. No-one is getting a .630 out of 130ELD... If thats the case, you are on the wrong path of crushing the axial adjustment.
 
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bd73

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#35
@bd73 run the G1 in the non-DOF calculator inside the Hornady app.. what kind of BC tweak do you need? I'd bet the same as in every other solver and very close to the 4DOF predictions before maxing out the Axial adjustment. No-one is getting a .630 out of 130ELD... If thats the case, you are on the wrong path of crushing the axial adjustment.
For some reason it didn't work. But I kind of agree. It's possible that the axial form is not the whole X here.
 

Long Range 338

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#36
Regardless, of the 4DOF calculator we know that at that range G1 numbers in AB, CB, FFS, Shooter you name it are all relatively close with correct inputs, even without curve fitting much. So there seems to be a red flag in there no matter how you look at it. 1 mil off at that close range isn't something that should be happening.

Going to the end to modify the 4DOF in this case seems extreme. I'd be somewhat concerned to tweak only one thing to it max, without going back and having several points to verify the curve fit adjustment. Ideally your shoot your zero, and several point to the end game the same day under the same conditions, "if" you wanted to be completely certain all was dialed.
^^^ This.

I tried running the numbers in Hornadys BC calculator and with the same inputs it was WAY off. If the BC is actually as high as you are thinking it is then the drops at 200, 300, 400, etc all the way out to 975m will be spot on. If not there is another variable being missed here.
 
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#37
It's pretty much clear to me that Hornady published 0.554 G1 is way off. No axial, no DC...if nothing helps so far to align the planets then we are before a clear and present wrong number.
 
Feb 7, 2013
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#38
Honestly, seems like a false return. Not a BC issue.. but of course, it can be a tiny bit of everything. But not just the BC.

I know sometimes you can be hard to believe but ranging cliff or not can present challenges even with milgrade tools.

I’ve made so many ranging mistakes over the years, this setup doesn’t sound unfamiliar.. we were just discussing mil ranging here- https://forum.snipershide.com/threa...ser-range-finder-whats-more-important.6878626 the point being a false return did play a part in my mess.

While I get the cliff face should be easy... anything can cause an issue, I’ve seen false fronts here too..

I don’t think the BC alone is off 13 % from other 130 BCs either or the 130s I’ve shot
 
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Feb 20, 2013
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#39
Honestly, seems like a false return. Not a BC issue.. but of course, it can be a tiny bit of everything. But not just the BC.

I know sometimes you can be hard to believe but ranging cliff or not can present challenges even with milgrade tools.

I’ve made so many ranging mistakes over the years, this setup doesn’t sound unfamiliar.. we were just discussing mil ranging here- https://forum.snipershide.com/threa...ser-range-finder-whats-more-important.6878626 the point being a false return did play a part in my mess.

While I get the cliff face should be easy... anything can cause an issue, I’ve seen false fronts here too..

I don’t think the BC alone is off 13 % from other 130 BCs either or the 130s I’ve shot
You may be right. I said the BC just because that's what's asked by the OP. But without the full data he used to calculate the fire solution it's just a wild guess.
 

Mordamer

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#41
This thread has me curious so I got some 130 ELD's loaded them up and shot some groups this morning. Accuracy was excellent and I'm getting right at 2,900 FPS with 38.0 grains of Varget in my 6.5x47 lapua with 1:8 twist 26" Bartlein barrel. Velocity checked with magneto speed.

I will test this load this weekend out to 1,300 yards and true up the B.C. to my actual dope. I'll try to report on here what I discover.
 

bd73

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#43
I will test this load this weekend out to 1,300 yards and true up the B.C. to my actual dope. I'll try to report on here what I discover.
Looking forward to hear the results of that. You got about the exact same speed as I do. On Saturday I will do a new test out 1315 meters (1440 yards) and I am excited to see if my results from last week will be reproduced.
 

bd73

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#44
What was the density altitude used in your calculations? What was the DA for your shooting? A significant DA difference could cause a good bit of difference as well.
DA was 445 meters. Both pressure, humidity and temperature was part of my calculation.
 

Mordamer

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#45
Looking forward to hear the results of that. You got about the exact same speed as I do. On Saturday I will do a new test out 1315 meters (1440 yards) and I am excited to see if my results from last week will be reproduced.
Here are the results of my test this morning.
Temp 30 degrees F
Humidity 27 %
Station pressure 27.2 inhg
Wind was 9 MPH from 10:30

Checked velocity with magneto speed and average was 2905 FPS with an SD of 7 and ES of 20.

Verified zero at 100 yards.

Ranged target with 2 separate Leica rangefinders at 1,314 yards. Target was a nearly vertical rock face with clay pigeons stuck on it. This makes it very easy to spot exact impact points. There was less than 1 degree vertical angle of our shots with us lower than the targets.

Shot over 20 shots at 1,314 and my dope was very consistent hits at 12.6 mils elevation. Scope is a Kahles 624i gen 3 and tracking is very good.

We then moved to 984 yards and shot the same targets and my dope was very consistent hits at 7.5 mils elevation.

With all environmental data correct in Strelok and all other inputs correct the closest G1 B.C. that produces these drop numbers is .615.

Please check my numbers and make sure I have not missed a variable.
 
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Mordamer

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#46
Also, I would like to add that I just input all my data into Hornady's 4DOF app and it exactly matches my dope from today. Pretty awesome. I may use their app more in the future instead of Strelok. I did not mess with axial form factor and left it at 1.
 

bd73

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#47
With all environmental data correct in Strelok and all other inputs correct the closest G1 B.C. that produces these drop numbers is .623. In Strelok Pro the G7 B.C. works out to be .298.
I did the same yesterday, and my data match a BC at .625, pretty close to yours. Cool to see that you get similar results as we did. Thanks for sharing.

And the results as started this post are verified. I still have to set the axial form factor to .9 to get the my dope in the Hornady app.
 
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Mordamer

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#48
I did the same yesterday, and my data match a BC at .625, pretty close to yours. Cool to see that you get similar results as we did. Thanks for sharing.

And the results as started this post are verified. I still have to set the axial form factor to .9 to get the my dope in the Hornady app.
I edited my above info to just show only G1 BC and I found that I left out Coriolis effect so with coriollis included it makes the B.C. slightly lower. My firing azimith was 80 degrees east of north and my latitude is 36 degrees.

Regardless, I believe the actual B.C. of the bullet if tested by others will show to be over .610 G1 as our tests showed. That is a huge difference from Hornady's published data. The numbers we are posting are not totally ridiculous as Nosler also has a 130 grain bullet with a G1 of .615.
 
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Nov 5, 2013
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#49
I ran about 4K of the Berger 130 hybrids when they first came out and love em... but have since switched to the 140 eld...if the130 eld’s have a bc up over .600, I might have to give them a shot
 

Apnea

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#50
Measuring impact height on target in 1st person on paper for steel vs 2nd person though a scope/spotter with a reticle on a rock face, would be another example (may not be applicable here) of a window where error could get into your ballistic "correction" technique.
Can you explain this a little more? Not sure I understand.
 
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