Applied Ballistics Data for Hornady ELD-Match 178 wrong

[German_Hunter]

Yesterday I was at the 1K Range with a proven Rifle/Ammo Combo, and was using the Kestrel Elite als Solver instead of Strelok Pro.
But I was way off target at 1K, with the Solution of the Ketsrel. So I started calibrating (more accurate: Bending) the Data, until I started to hit again.
Today at Home i started to compare, and realized that the Data in the Applied Ballistics Database for the
.30 Hornady ELD Match 178grs is wrong. Even the G7 BC is over Hornadys Claim.... I cannot look into the custom drag curve, but the solution compared to a stepped G7 Solution in Strelok Pro is way off.
This is already the second time, because I´ve had the same issue with Hornady´s ELD X Bullet in AB´sr Database, which was corrected.

Long Range Shooting possibilities are rare in germany, and it´s a real PITA, when you realize, you´ve wasted a day of precious range time, and a lot of ammo. All because the "Most Advanced/Accurate ballistic solver on the market. Trusted by Professionals" gives you wrong data.....

Please take care of that.

 

[Steel head]

AB’s ballistic program can’t account for rifle differences and other variables out of their control.

It’s not a magic box.

Even Hornandy’s own 4dof program with their bullets usually needs tweaking.

You need to bend the program to fit what the bullets tell you because your not gonna bend the bullets to fit the program.

Once you you tweak the data to fit the actuals is when ballistic computers shine.

Another important aspect.

When you start lofting bullets high in the air to hit distant targets they can often meet winds you don’t detect at ground level.

That’s things you need to document as it’s often location, time and direction specific.

How’s some ballistic program supposed to account for that?

That’s your job and it takes time, experience and notes.

You also need to double check all data to ensure everything jives.
That includes BC’s.

They might be using box numbers instead of Hornandy’s listed lower Mach numbers which are closer to actual BC’s at long distance.

 

[German_Hunter]

No, it´s not a magic box. They work on the garbage in - garbage out principle.

When I do my part -as I usually do- and carefully gather and measure all the Rifle, scope, zero and weather input data as well as Labradar measured speed, yes even temperature dependence of bullet speed, and use a valid BC/Custom Drag curve with it.... It should be able to calculate the drop exactly.

So does strelok pro with hornady´s mach dependent BC´s. Hornadys 4DOF Calculator calls for "axial form factor", which is exactly what you describe, but in reality it is just compensating other errors.
A ballistic solver, fed with correct, accurate Data, should be able to predict the flight path without needing to "bend" valid input data.

Everything else would not make sense. You would not need ballistic solvers if it was just a rough approximation.
I KNOW my Bullet Speed, I KNOW my Sight Hight, I KNOW my younameit..... Why should I change KNOWN Values, just to fit the equation if the CD/BC is causing it....
If your car pulls to the left, because of a flat tire..... would you release air from the right tire as well, to balance that out, or would it be better to inflate the left one ?

Since I did a direct comparison with the exact same input data, exept AB´s Custom Drag Curve in the Kestrel vs. Hornady´s mach dependend G7 BC´s in Strelok pro, it is the most likely source of error, not the other variables, that worked in the past....

As I wrote above, I had the same issue with ELD-X Custom Drag Curve once. You can check here on Snipers Hide Forum, that @DocUSMCRetired suggested to use the Data for the ELD-Match Bullet instead, when I complained that those bullets are very different. Then he clearified, that the curve is the correct one for ELD-X, but labelled wrong. They corrected that, which can be seen in their changelog.

Now I suspect, that they just copied the wrong labelled File, renamed it, and kept the source file with old name, but wrong Data. Just speculation, but from the predicted drag behavior of the ELD-Match Bullet in AB´s Database, it is very plausible, that those are still ELD-X Values.....

 

[Dthomas3523]

No, it´s not a magic box. They work on the garbage in - garbage out principle.

When I do my part -as I usually do- and carefully gather and measure all the Rifle, scope, zero and weather input data as well as Labradar measured speed, yes even temperature dependence of bullet speed, and use a valid BC/Custom Drag curve with it.... It should be able to calculate the drop exactly.

So does strelok pro with hornady´s mach dependent BC´s. Hornadys 4DOF Calculator calls for "axial form factor", which is exactly what you describe, but in reality it is just compensating other errors.
A ballistic solver, fed with correct, accurate Data, should be able to predict the flight path without needing to "bend" valid input data.

Everything else would not make sense. You would not need ballistic solvers if it was just a rough approximation.
I KNOW my Bullet Speed, I KNOW my Sight Hight, I KNOW my younameit..... Why should I change KNOWN Values, just to fit the equation if the CD/BC is causing it....
If your car pulls to the left, because of a flat tire..... would you release air from the right tire as well, to balance that out, or would it be better to inflate the left one ?

Yes, in a world where humans have figured out the exact math behind external ballistics and can account for every nuance in every barrel every created, and every shooter’s fundamentals or lack thereof........

But that’s not the world we live in.

The math hasn’t been perfected and there’s countless variables in which we can’t solve for.

It takes literally 20min or less to true your data up.

Your car example is a terrible one, not even going to dive into the many reasons why.

I don’t care if I have to tweak the MV or the BC to make the software line up. Because I can’t go in an change the math it wants to use. I can only change the BC and/or the MV.

There’s guys that have fits because their chrono says 2980, but software wants to use 3025 to make the data line up. They claim to have lost a day at the range.

Then there’s people who plug in the 3025 and keep moving.

 

[German_Hunter]

I´m sorry to tell you, that external ballistics has nothing to do with your barrel (what happens inside the barrel is internal ballistics)..... Bullet is leaving barrel with a certain veloctity and a certain rotational speed. That´s the point where external ballistic starts and the ballistic calculator kicks in. How those 2 values are beeing created by your barrel is irrelevant for your ballistic calculator....

I care what to tweak, because it matters. There´s a suggestion to use MV to compensate for wrong BC. Well guess what, your wind values will be off too, if you turn that wrong screw..... And I did get the issue solved on the range, as I wrote above. I´ve bent the values to match my observations, but that does not make the solution right. That works just on that day on that range. Any other day on another range, your false data will cause different problems. So I want to have it right....

I can get anyone to hit on 1K if I let them shoot, correct them, let them shoot again and so on. Thats no big deal. Anyone can do that, even with completely unknown setup.
But getting the first round of the day on target in formally unknown conditions is a totally different game, that requires much more paying attention to those small details.

 

[morganlamprecht]

sounds like the OP knows everything except what he doesnt know....rough position to be in

 

[Steel head]

I´m sorry to tell you, that external ballistics has nothing to do with your barrel (what happens inside the barrel is internal ballistics)..... Bullet is leaving barrel with a certain veloctity and a certain rotational speed.

Lol.

A lot more than speed and twist is imparted to the bullet from the barrel and/or the muzzle device on the end of it.

They’re a big reason we have to true data.

You think a bullet comes out all the time with a perfect spin every time?

 

[German_Hunter]

We´re drifting a little off topic here.... Pitch, yaw and twist stabilisation is all effect of those 2 values (+ Bullet parameter of course). Even BC reduction because of understabilisation is a result of Velocity, Spin Rate and of Course Bullet Form/Shape/Weight....
Yes, it is caused by internal ballistics, but per definition we are trying to calculate path of flight, which is an outer ballistics topic.....
So why should I consider inner ballistic, when trying to solve outer ballistic problems ? Inner Ballistic is finished, when the outer ballistic problem starts.

Asked differently: How would knownig e.g friction or gas pressure in a barrel help to predict path of flight ?
Wouldn´t help at all.....

 

[Steel head]

You don’t think pitch and yaw doesn’t effect BC?

 

[German_Hunter]

I didn´t say that. Of course it does.
"Even BC reduction because of understabilisation is a result of Velocity, Spin Rate and of Course Bullet Form/Shape/Weight.... "

 

[Lowlight]

Internal Ballistics do matter and Hornady has been putting out data demonstrating the downrange changes they see via Doppler Radar

Other elements also have a factor

There is more but I believe this makes the point. it even shows powder difference and it's effect downrange.

As well you are comparing 3DOF software vs 4DOF software where one has Pitch & Yaw native the other does not.

These are all just starting points, averages based on the systems used, the shooter and the comparison between the test systems and the actual ones being shot. While there is author influence, where they add in their own flourishes, it's pretty close to right, most are within .2 Mils of actual if you are doing your part correctly. Yes AB takes a few liberties of other manufacturers data, we have seen this, but again, averages based on their system, not yours.

BC are dynamic, the number on the box is not necessarily your number and the AB numbers are again just averaged to get you started.

The Human Influence is also noticeable in software, how someone shoots and manages the shot has a commanding difference on the results as we include a lot of "US" in the shot hence the need to true to our system including us.

Everything has a variable, whether we see it or not is the questions. The bottom line is, the Rifle and Shot cannot match the computer, the Computer has to be matched to the Rifle System and Shooter, not the other way around.

The software assumes a vacuum and it does not know where the bullet was before that point in space, so we true.

AB can be very good if you put in the effort to line it up correctly and I don't always recommend doing it via their utilities but rather manually and we find the software works very good. But it is just 3DOF.

It's very rare to put in raw data point and be exactly right the first time without calibration and truing.

 

[FN-Whitney]

Quite often I find the hardest thing about truing data is determining how much influence I had on the shot. I have had to go back about every 6 months and re-true data as I have improved as a shooter.

 

[Ledzep]

Frank beat me to it.

CD vs. velocity curves can change (slightly) when I shoot 2 bullets from the same lot, in the same rifle. If the first shot is bare muzzle, then the 2nd has a muzzle brake, the braked shot (POI/POA differences aside) will typically have more drag throughout the trajectory because of what's going on with muzzle exit gases.

Likewise different rifling patterns, twist rates, etc. can all affect CD vs. velocity by engraving/damaging the bullet differently, giving it a different shape as it flies through the air. Long story short there are a lot of small differences that start to add up the farther you away you shoot and become more and more noticeable and will require correction.

So yes, part of that is for AB to get correct CD data into their system-- can't comment there; I'm not familiar with AB solvers at all, but like Frank said, there's also a lot of stuff that can change output on your end that starts out very miniscule.

 

[DocUSMCRetired]

The data for that bullet is good data(the 178). We are constantly testing, and re-testing bullets from lot to lot. I just checked it, and its solid data.

I can tell you we just finished some testing on the A-Tips, and some others. Including new testing on both the 140 & 143. I won't comment on the A-Tips just yet. However the difference in performance between the 143 and 140 ended up as an averaged 0.001 G7 BC with the previous lots we tested. Now we have re-tested them and the new lots for both bullets had enough of a difference to trigger our system to suggest an update to both bullet models. We have 2 Hornady and 3 Sierra bullets which are receiving updated information right now.

If you combine the two updates it comes to 16 New Centerfire, 11 New Rimfire, and 10 Updated Bullet Models.

 

[German_Hunter]

The data for that bullet is good data(the 178). We are constantly testing, and re-testing bullets from lot to lot. I just checked it, and its solid data.

I can tell you we just finished some testing on the A-Tips, and some others. Including new testing on both the 140 & 143. I won't comment on the A-Tips just yet. However the difference in performance between the 143 and 140 ended up as an averaged 0.001 G7 BC with the previous lots we tested. Now we have re-tested them and the new lots for both bullets had enough of a difference to trigger our system to suggest an update to both bullet models. We have 2 Hornady and 3 Sierra bullets which are receiving updated information right now.

If you combine the two updates it comes to 16 New Centerfire, 11 New Rimfire, and 10 Updated Bullet Models.

@DocUSMCRetired
Thanks for the clearification. We usually buy larger quantities from one lot, when bullets are available, since they are somewhat hard to get here in germany. From those ELD-Match 178 for example, I bought 4000. I have 2500 ELD-X on backorder for almost a year, now.

So everytime any manufacturer changes something you´re changing your curve ? Do you keep track of the Lot Numbers and do you still have the old files ? Could you append new files, instead of replacing the old ones ?

I´m asking because it would be very unpleasant, If someone had confirmed Data, and next time he uploads it again to the kestrel (for whatever reason) the tried and trued data is updated, but the bullet lot is not....

 

[Dthomas3523]

I´m sorry to tell you, that external ballistics has nothing to do with your barrel (what happens inside the barrel is internal ballistics)..... Bullet is leaving barrel with a certain veloctity and a certain rotational speed. That´s the point where external ballistic starts and the ballistic calculator kicks in. How those 2 values are beeing created by your barrel is irrelevant for your ballistic calculator....

I care what to tweak, because it matters. There´s a suggestion to use MV to compensate for wrong BC. Well guess what, your wind values will be off too, if you turn that wrong screw..... And I did get the issue solved on the range, as I wrote above. I´ve bent the values to match my observations, but that does not make the solution right. That works just on that day on that range. Any other day on another range, your false data will cause different problems. So I want to have it right....

I can get anyone to hit on 1K if I let them shoot, correct them, let them shoot again and so on. Thats no big deal. Anyone can do that, even with completely unknown setup.
But getting the first round of the day on target in formally unknown conditions is a totally different game, that requires much more paying attention to those small details.

Everything you said here is wrong.

So wrong that it’s too much to even correct. I’d suggest throwing out everything you think you know and learn a bit more about software.

It’s not a perfect world and you’re going to have to bend data at times because those are the only variables that we can change on the user end.

Funny that everyone else can “bend” those variables and the software gives them good solutions everyday after.

 

[Dthomas3523]

Short story: as long as I’m not changing things too drastically, I don’t give a shit if I have to tweak the bore height, velocity, or BC to make the calculator match up to real world data. Because those are the only inputs I can change. And once those are changed, it will give me correct solutions from then on out.

Man, I’d wish it was affordable for guys to have Doppler and such to check their actual BC.

The way people lose their minds about making sure the chrono speed works out in the calculator........I’d love to see when the BC they have been using for years turns out not the be the actual intrument measured B.C. and they’ve been lying to the software for years.

We trust the software when we change B.C. because we can’t measure that at the end user level. But lose our collective shit when we tweak our measured velocity 1-2%.

 

[Dthomas3523]

@DocUSMCRetired
Thanks for the clearification. We usually buy larger quantities from one lot, when bullets are available, since they are somewhat hard to get here in germany. From those ELD-Match 178 for example, I bought 4000. I have 2500 ELD-X on backorder for almost a year, now.

So everytime any manufacturer changes something you´re changing your curve ? Do you keep track of the Lot Numbers and do you still have the old files ? Could you append new files, instead of replacing the old ones ?

I´m asking because it would be very unpleasant, If someone had confirmed Data, and next time he uploads it again to the kestrel (for whatever reason) the tried and trued data is updated, but the bullet lot is not....

You should be re-checking and truing at anytime you get a new lot of bullets, ammo, or powder.

That eliminates having to hope you have the most updated AB data. That’s just a starting point.

You don’t shoot say, 108 eld bullets from a lot of 1k bullets, and then when you buy 1k of another lot, assume it’s going to be the same.

When your backordered 2500 come in, if they aren’t they same lot, you need to re-true your data.

 

[German_Hunter]

Maybe it´s because I´m not writing in my native language, and cannot express myself as good as in german, but most of you miss my point...

You should be re-checking and truing at anytime you get a new lot of bullets, ammo, or powder.

Yes, without doubt. But I have a large Lot of Ammo, loaded with the same components. They will last minimum for the next 2 years and I don´t want AB to change my working firing solution externally, by serving me newer Bullets Drag Curves, I don´t need.....

My Request would be: to be able to pick from their measured curves the one, that fits my lot best, and leave that until I have a new lot. Beeing able to chose for myself, which ELD-Match Curve to chose.
The way it is now, one might end up in a situation, where the profile, that was spot on for your setup -is beeing changed externally by exchanging the Custom Drag Curve in their AB Connect Database.
How ? Even though on of the last entries in Kestrels Firmware changelog says: Firmware Upgrade will no longer delite profile, it happened when I updated to 1.27. So I had to relaod my profile from App to Kestrel, which is beeing equipped with the latest custom drag curve for the chosen bullet from AB´s Database.

It would be much more user friendly, if they would append new lot measurements, instead of replacing everytime. In the spirit of "Never change a running system".
This way, there will be no changes in firing solution when there are no changes in hardware. I -as user- can decide, when it´s time to change my data, becaue I know when I changed my lot of bullets.

That eliminates having to hope you have the most updated AB data. That’s just a starting point.

The Opposite is the case: If I have a matching curve, I don´t want that beeing changed externally.
Right now -to prevent that happening-using the kestrel, I could only use a single G7 BC that I found to be matching (and is nothing near the published data - changed it, until it matched my observations) But the Kestrel Elite is all about the Custom Drag Curves, and I would like to use them too....
And before you pick on that one too: Hornady has published a 3 stepped G7 BC. My single G7 BC in the Kestrel is between the last 2 Veleocity steps - so plausible when considering I´m having to use a single BC, when in reality it decays over flight time.

You don’t shoot say, 108 eld bullets from a lot of 1k bullets, and then when you buy 1k of another lot, assume it’s going to be the same.

No I don´t. New Lot, New Game.... That´s another benefit of buying bulk..... You usually don´t have to change your Data that often.

When your backordered 2500 come in, if they aren’t they same lot, you need to re-true your data.

WIthout doubt, but that was not my point, as you hopefully can see now. Only that my approach to truing is different. While most of you are soultion oriented (Accepting MV Correction, when in reality BC has changed, or because you can´t change custom drag curve), I like to change the value that is causing the deviation. Maybe it´s the same result in the end, but I -for me- observed those inaccuracies to cause different problems. So I try to avoid them.
My opinion... you don´t need to share it, but I ask you to accept it.

 

[DocUSMCRetired]

@DocUSMCRetired
Thanks for the clearification. We usually buy larger quantities from one lot, when bullets are available, since they are somewhat hard to get here in germany. From those ELD-Match 178 for example, I bought 4000. I have 2500 ELD-X on backorder for almost a year, now.

So everytime any manufacturer changes something you´re changing your curve ? Do you keep track of the Lot Numbers and do you still have the old files ? Could you append new files, instead of replacing the old ones ?

I´m asking because it would be very unpleasant, If someone had confirmed Data, and next time he uploads it again to the kestrel (for whatever reason) the tried and trued data is updated, but the bullet lot is not....

TLDR - Profiles are in no way changed during a library update. Only the internal library is changed. In order to get the new data, a user would have to have generated a new profile.

--------------------------------------

The system is designed so that it does not change rifle profiles that are already built. So updating the library will not affect old saved profiles. Only new ones which are created.

We have thought about this approach, and I do have a library that dates back about a decade on this computer. But the issue is that would create a massive amount of data on your device. We are looking into possible ways to sort by lot number though. However your old profiles are not updated when a library update occurs. In fact, in order to get the new data, you have to generate a new profile after the update.

 

[DocUSMCRetired]

Short story: as long as I’m not changing things too drastically, I don’t give a shit if I have to tweak the bore height, velocity, or BC to make the calculator match up to real world data. Because those are the only inputs I can change. And once those are changed, it will give me correct solutions from then on out.

Man, I’d wish it was affordable for guys to have Doppler and such to check their actual BC.

The way people lose their minds about making sure the chrono speed works out in the calculator........I’d love to see when the BC they have been using for years turns out not the be the actual intrument measured B.C. and they’ve been lying to the software for years.

We trust the software when we change B.C. because we can’t measure that at the end user level. But lose our collective shit when we tweak our measured velocity 1-2%.

TLDR - A BC is actually only true at a specific velocity. A Bullets BC will change throughout its flight. Most software should use an averaged BC (multiple BCs averaged together) that attempts to best represent what the user is doing. This is the biggest reason you should never use the BC on a box of bullets, its for marketing and not represenetative of long range flight in many cases (some exceptions exist, Like Berger's which we provide the BC for that goes on the box). Using the actual flight data (Custom Drag Model) for that bullet from 3000fps to 500 fps (which includes the much more crucial transonic data) will always provide accurate flight predictions. However it cannot account for changes in performance caused by the User and the Equipment (Well that is not entirely true, as ours can because it has some inputs for these variables. But only if they are used correctly) .

-----------------------------

Their is a bit of at fault on our part here too. An assumption is made that a BC = Bullet Performance. This is just simply not true. A good analogy that seems to be working for people lately is this. Lets say you go car shopping. You look at the sticker on the window and it says you get "25 mpg highway". You buy the vehicle, and you start driving at your speed limit which is around 85 mph legally. You find you cannot get said 25 mpg highway, unless you are doing speeds closer to 70mph.You find that mpg is actually tied to a specific speed, and going faster or slower changes your results.

BC works in the same way. A BC is only true at a specific velocity and will often change (if you go through transonic zone in many cases by more than 100%). A BC is actually true at a specific Mach number. It shifts as that Mach Number shifts. But we try to provide the best averaged BC which is relevant and will provide the shooter with good results. However, when shooting through the transonic zone nothing is going to beat a CDM. Because the CDM consists of data that is often from 3000 fps to 500 fps. A lot of our recent testing is beyond 3 sec (2000 yard) flights computed via RADAR. So you are talking exponentially more data points for the prediction model to use, vs a single BC.

 

[Country]

No single BC can predict a whole trajectory with equal accuracy .
When I model a G1 bullet I make I get a whole list of BC's which one is right ?
Obviously they are all right for the relevant velocity but to chose a single one or an average of a few is still an approximation compared to the whole trajectory .
For me not a problem as it's only a 500 meter hunting bullet but for longer range shooters you really need multiple BC's at velocity intervals to get a better approximation .

 

[German_Hunter]

TLDR - Profiles are in no way changed during a library update. Only the internal library is changed. In order to get the new data, a user would have to have generated a new profile.

--------------------------------------

The system is designed so that it does not change rifle profiles that are already built. So updating the library will not affect old saved profiles. Only new ones which are created.

We have thought about this approach, and I do have a library that dates back about a decade on this computer. But the issue is that would create a massive amount of data on your device. We are looking into possible ways to sort by lot number though. However your old profiles are not updated when a library update occurs. In fact, in order to get the new data, you have to generate a new profile after the update.

Thanks again for clearification. Even though it is not as bad as thought, but it still leaves me somehow restricted control over my data.
There is no possibility to safe an existing profile outside the mobile phone. So if I change phones (average user every 1-2 years), I have to read it from the kestrel, and hope there have been no changes. But can´t really see, what I´m using. Anytime, I have to recreate a profile, I will be in the situation to use a maybe updated custom drag curve.

In times of GigaBytes of storage on mobile phones, what is massive amount of data ?
Would really appreciate it, if you could figure out a way to make all of your measurements available.

Since Access to your AB Connect Database was the original reason to buy and use the kestrel elite, it would be a great benefit.
Thanks again for joining in, and sharing this great information with us.

 

[Dthomas3523]

TLDR - A BC is actually only true at a specific velocity. A Bullets BC will change throughout its flight. Most software should use an averaged BC (multiple BCs averaged together) that attempts to best represent what the user is doing. This is the biggest reason you should never use the BC on a box of bullets, its for marketing and not represenetative of long range flight in many cases (some exceptions exist, Like Berger's which we provide the BC for that goes on the box). Using the actual flight data (Custom Drag Model) for that bullet from 3000fps to 500 fps (which includes the much more crucial transonic data) will always provide accurate flight predictions. However it cannot account for changes in performance caused by the User and the Equipment (Well that is not entirely true, as ours can because it has some inputs for these variables. But only if they are used correctly) .

-----------------------------

Their is a bit of at fault on our part here too. An assumption is made that a BC = Bullet Performance. This is just simply not true. A good analogy that seems to be working for people lately is this. Lets say you go car shopping. You look at the sticker on the window and it says you get "25 mpg highway". You buy the vehicle, and you start driving at your speed limit which is around 85 mph legally. You find you cannot get said 25 mpg highway, unless you are doing speeds closer to 70mph.You find that mpg is actually tied to a specific speed, and going faster or slower changes your results.

BC works in the same way. A BC is only true at a specific velocity and will often change (if you go through transonic zone in many cases by more than 100%). A BC is actually true at a specific Mach number. It shifts as that Mach Number shifts. But we try to provide the best averaged BC which is relevant and will provide the shooter with good results. However, when shooting through the transonic zone nothing is going to beat a CDM. Because the CDM consists of data that is often from 3000 fps to 500 fps. A lot of our recent testing is beyond 3 sec (2000 yard) flights computed via RADAR. So you are talking exponentially more data points for the prediction model to use, vs a single BC.

Are you seriously as a representative for a company using TLDR??

And then going into an explanation, after that??

No wonder you guys get a reputation for not caring or listening to your consumers.

 

[Dthomas3523]

Maybe it´s because I´m not writing in my native language, and cannot express myself as good as in german, but most of you miss my point...


Yes, without doubt. But I have a large Lot of Ammo, loaded with the same components. They will last minimum for the next 2 years and I don´t want AB to change my working firing solution externally, by serving me newer Bullets Drag Curves, I don´t need.....

My Request would be: to be able to pick from their measured curves the one, that fits my lot best, and leave that until I have a new lot. Beeing able to chose for myself, which ELD-Match Curve to chose.
The way it is now, one might end up in a situation, where the profile, that was spot on for your setup -is beeing changed externally by exchanging the Custom Drag Curve in their AB Connect Database.
How ? Even though on of the last entries in Kestrels Firmware changelog says: Firmware Upgrade will no longer delite profile, it happened when I updated to 1.27. So I had to relaod my profile from App to Kestrel, which is beeing equipped with the latest custom drag curve for the chosen bullet from AB´s Database.

It would be much more user friendly, if they would append new lot measurements, instead of replacing everytime. In the spirit of "Never change a running system".
This way, there will be no changes in firing solution when there are no changes in hardware. I -as user- can decide, when it´s time to change my data, becaue I know when I changed my lot of bullets.


The Opposite is the case: If I have a matching curve, I don´t want that beeing changed externally.
Right now -to prevent that happening-using the kestrel, I could only use a single G7 BC that I found to be matching (and is nothing near the published data - changed it, until it matched my observations) But the Kestrel Elite is all about the Custom Drag Curves, and I would like to use them too....
And before you pick on that one too: Hornady has published a 3 stepped G7 BC. My single G7 BC in the Kestrel is between the last 2 Veleocity steps - so plausible when considering I´m having to use a single BC, when in reality it decays over flight time.


No I don´t. New Lot, New Game.... That´s another benefit of buying bulk..... You usually don´t have to change your Data that often.


WIthout doubt, but that was not my point, as you hopefully can see now. Only that my approach to truing is different. While most of you are soultion oriented (Accepting MV Correction, when in reality BC has changed, or because you can´t change custom drag curve), I like to change the value that is causing the deviation. Maybe it´s the same result in the end, but I -for me- observed those inaccuracies to cause different problems. So I try to avoid them.
My opinion... you don´t need to share it, but I ask you to accept it.

Dude......if you want to use the custom drag curves, you have to tweak MV to make it work if it doesn’t line up perfectly to begin with.

Which goes against your earlier opinion of not messing with MV.

Make up your mind.

 

[German_Hunter]

Dude.... Seriously.... I'm out of that discussion with you....

 

[Country]

If you are keeping your precision ammo loaded for two years just neck tension changes alone over two years will screw up some accuracy potential . Look up stress corrosion in brass .
If you are reloading them my advice is moly coat your projectiles as that fights neck weld and only partial seat the bullets . That way just before use you seat the ones you need fully . That evens up neck tension somewhat .

 

[DocUSMCRetired]

Dude......if you want to use the custom drag curves, you have to tweak MV to make it work if it doesn’t line up perfectly to begin with.

Which goes against your earlier opinion of not messing with MV.

Make up your mind.

If you use Custom Drag Models you are able to ballistically true, and to use muzzle velocity adjustments. Both methods are available if you use a G1/G7 or if you use a CDM.

 

[DocUSMCRetired]

Thanks again for clearification. Even though it is not as bad as thought, but it still leaves me somehow restricted control over my data.
There is no possibility to safe an existing profile outside the mobile phone. So if I change phones (average user every 1-2 years), I have to read it from the kestrel, and hope there have been no changes. But can´t really see, what I´m using. Anytime, I have to recreate a profile, I will be in the situation to use a maybe updated custom drag curve.

In times of GigaBytes of storage on mobile phones, what is massive amount of data ?
Would really appreciate it, if you could figure out a way to make all of your measurements available.

Since Access to your AB Connect Database was the original reason to buy and use the kestrel elite, it would be a great benefit.
Thanks again for joining in, and sharing this great information with us.

The CDM data will always remain encrypted. This is to keep the data out of other applications which routinely harvest what we do publish for their own use without the effort or cost of developing that data.

However we are starting to field a new cloud system which will allow for cross application transfers and backup of profiles.

 

[davere]

The system is designed so that it does not change rifle profiles that are already built. So updating the library will not affect old saved profiles. Only new ones which are created.

One thing to note - until the most recent Kestrel update, a user would potentially be creating a new profile any time he updated his Kestrel, if the gun profiles were lost during the upgrade. I recently lost all of mine trying to get my Kestrel onto the latest software, for instance. That problem was apparently corrected moving forward, so we shouldn't see it again - just pointing out that while AB has done the work to try to ensure that a profile doesn't get updated silently on the user, that's not a 100% guarantee that the user will never end up with the profile changing due to factors outside AB's control.

 

[alex2x2]

to

DocUSMCRetired​

Hello! I have the same issue with .30 cal 178 ELD Match bullet. MV is 836 mps, twist rate 1:12
Sight height 6.8 cm

I've bought several CDMs 178 ELD Match included. I've bought Kestrel 5700 Elitewith AB, but my dope donot match neither CDM , nor G7 BC 0.276
Rem 700 .308
MV is 836 mps,
twist rate 1:12
sight height 6.8 cm
temp +18
Rh 77%
St pressure 986 hPa
wind speed 2.0 mps
wind angle 8 clock

my real dope is
500 m 3.3 mil Kestrel 3.20
575 m 4.0 mil Kestrel 4.06
640 m 4.9 mil Kestrel 4.86
730 m 6.0 mil Kestrel 6.08
800 m 7.1 mil Kestrel 7.12
837 m 7.7 mil Kestrel 7.71
930 m 9.6 mil Kestrel 9.31 don't match

If I try to true MV to 825 mps this dope (930 m) match, but all above don't.

How can I fix it ?

Sorry for my English

 

[Lowlight]

You have to adjust the MV as they said above,

A CDM is still based on "their" rifle, and how it shot that ammo, this is not tuned to you, or your system, it's still an average.

A CDM is not a magic fix, you true with the MV if it does not line up. BCs are fluid, they are not a set in stone number, neither is a CDM. Your system is still your system and is not what they used, nor do you shoot like them, which software does not account for the biggest variable we have, US ... the shooter.

 

[alex2x2]

You have to adjust the MV as they said above,

My Kestrel or AB app say me to reduce MV to 825 mps. My dope from 0 to 800m don't match

 

[Lowlight]

Ya, it won't match until you true it...

maybe it's the language barrier, but you have to adjust it to match, nothing is going to match out of the box

The software only has the ability to adjust it via the MV, so you have to change that to line up.

It always requires an adjustment, when it doesn't consider yourself lucky, but 90% of the time you are adjusting the variables to match even if that variables are no longer in line with what you recorded.

If you adjust your MV down 75fps (or in your case m) the 930m will likely be close to matching

 

[Im2bent]

Create 2 profiles? One for short range one for long range?

 

[alex2x2]

maybe it's the language barrier

sorry for my English

It always requires an adjustment, when it doesn't consider yourself lucky, but 90% of the time you are adjusting the variables to match even if that variables are no longer in line with what you recorded.

I did not know it

If you adjust your MV down 75fps (or in your case m) the 930m will likely be close to matching

825 mps (2706.7 fps) in my case

 

[alex2x2]

Create 2 profiles? One for short range one for long range?

brilliant idea !!!Thanks

 

[Lowlight]

If you just used the BC instead of the CDM you could balance the curve and adjust both, which makes life easier.

You adjust the MV at 600 to line up those numbers then if you still need a tweak for the further ranges you adjust the BC number. MV changes the short ranges, BC helps adjust the long-range numbers without corrupting the short-range data.

So MV at 600 and BC at 800, this adjustment usually keeps things tuned, even when traveling beyond 4000ft DA.

 

[alex2x2]

If you just used the BC instead of the CDM you could balance the curve and adjust both, which makes life easier.

You adjust the MV at 600 to line up those numbers then if you still need a tweak for the further ranges you adjust the BC number. MV changes the short ranges, BC helps adjust the long-range numbers without corrupting the short-range data.

So MV at 600 and BC at 800, this adjustment usually keeps things tuned, even when traveling beyond 4000ft DA.

thanks. I'll try it.

 

[Im2bent]

That's why he's the HMFIC

 

[alex2x2]

You adjust the MV at 600 to line up those numbers then if you still need a tweak for the further ranges you adjust the BC number.

Do i need to adjust MV even though it is accurate?
I've measured it by LabRadar.

 

[gasrat]

Do i need to adjust MV even though it is accurate?
I've measured it by LabRadar.

I'd actually go out and true my data no matter what chrono was used. I do anyway.

 

[alex2x2]

Hornady ELD Match 178 gr from Applied Ballistics library

CDM and 0.275 G7 BC are wrong.

{PDM} Hornady ELD Match(237) and 0.262 G7 BC are correct

Multiple BC is correct

 

[DocRDS]

Hornady ELD Match 178 gr from Applied Ballistics library

CDM and 0.275 G7 BC are wrong.

{PDM} Hornady ELD Match(237) and 0.262 G7 BC are correct

Multiple BC is correct

I think we have to stop with this XXX is wrong.

There is a saying in Data Science: "All Models are Wrong, Some models are useful"

The defaults settings are the default. It isn't a plug and play. You always need to 'tune' (or true as the lingo is here) the model to your setup. The things you have available to tune the model are BC and MV. There are not really measured values. They are tuning parameters. Knobs if you will to make the outputs match the real world. Your measured values are start points to give you an idea. You actual dope at the range gives you the final values for your setup so that the Ballistic Calculator model is now useful to you.

People need to start asking themselves "What is more important--that the MV and BC of my kestrel match the published results/chronograph or that my bullet hits where the calculator says it should hit."

If its the former, you probably should not buy a ballistics calculator.