In the Hornady app using zero angle, I am having an issue where when I input my impact height (ex: 0.5" low) and save, it creates a zero angle, say .06906. If I go back in to the zero angle function, it then shows my impact height to be "0" again. If I put it back in again to .05" low, it creates a new zero angle, .007622. It's like it doesn't hold the impact height setting, visibly, but obviously is doing some type of stacking when I re-enter it. All other parameters under zero angle hold up after the save. Is this a bug?
4DOF Zero Angle is not "sticking"
- Thread starter Burdy
- Start date
Please write out the complete list of variables you're inputting on the "Find zero angle" page, as well as the specs for building the rifle profile. I know it's a pain in the ass but it really helps to ensure when others try to replicate the issue they're doing the same thing you are. Often enough, it also shows why different results are being output, too 
No problem at all:Please write out the complete list of variables you're inputting on the "Find zero angle" page, as well as the specs for building the rifle profile. I know it's a pain in the ass but it really helps to ensure when others try to replicate the issue they're doing the same thing you are. Often enough, it also shows why different results are being output, too
MV: 2520
Distance: 100 yds
Sight Height: 1.85
Twist: 8
Angle: 0
Altitude: 1848
Pressure: 28.17
Temp: 84
Humidity: 67
Wind: 0
Impact Height: It shows zero, but I keep putting in -0.5"
Impact Windage: 0
143 ELDX-6.5CM
Baseline Temp: 84
Temp Sensitivity: 0
As a point of clarification, every time you enter the "Find zero angle" page, it clears the impact locations from the last time you entered it. It will always say 0,0. That button is to open a tool to calculate zero angle, and it doesn't store or remember the last inputs for the current ZA. If you want to verify the outputs, you should go to the HUD and input 100yd, zero wind and make sure that it tells you to come up the equivalent angular measure for 0.5" at 100yd (0.14 mils, 0.48 MOA).
When I put in your information (and there may be some slight changes, mine vs. yours-- earth based effects on/off is usually the biggest offender), with impact -0.5" I get 0.0666. When I open it and re-enter -0.5" I get 0.0666 again.
However, your initial post you wrote both -0.5" and -0.05", and when I enter -0.05" I get 0.07376.
When I put in your information (and there may be some slight changes, mine vs. yours-- earth based effects on/off is usually the biggest offender), with impact -0.5" I get 0.0666. When I open it and re-enter -0.5" I get 0.0666 again.
However, your initial post you wrote both -0.5" and -0.05", and when I enter -0.05" I get 0.07376.
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Ok. you are correct. Thank you for that explanation.
With all of the parameter set as above, the hard dope of the gun is inside .1 mil of 4DOF, and spot on at 800.
However I require .2 mil extra at 1k. Does this seam reasonable? When I adjust for that .2 using the come up calibration, I ended up about .1 mil off at previous yardages (800 down to 300)
Does the below workflow look correct? In my case I made zero adjustment to velocity from my avg chrono reading (45 rounds)
| Initial Setup | ||||
| 1.) Under "Bullet" Locate correct bullet in app | ||||
| 2.) Under "Set Load Info", input the temperature when you took your muzzle velocity | ||||
| 3.) Under "Set Rifle Info" input your avg muzzle velocity at the temp from above | ||||
| 4.) Enter your sight height over bore in inches | ||||
| 5.) Enter your barrel twist rate | ||||
| How to Zero (can be done anywhere) | ||||
| 1.) Under "Set Rifle Info" select "Find Zero Angle" | ||||
| 2.) Zero as close to dead center of the target as possible | ||||
| 3.) Measure the distance in elevation and windage off center | ||||
| 4.) Enter velocity at time of zero | ||||
| 5.) Enter EXACT target distance, ex: 101 yards | ||||
| 6.) Enter exact angle from target, ex: 1 degree | ||||
| 7.) Enter altitude at zero location | ||||
| 8.) Enter absolute pressure at zero location | ||||
| 9.) Enter temparature at zero location | ||||
| 10.) Enter humidity at zero location | ||||
| 11.) Enter ANY wind speed and wind direction at zero location, ex: 1mph, 90 degrees | ||||
| 12.) Enter the distance up or down from center of your group size, ex: -.25" low | ||||
| 13.) Enter the distance left and right from the center of your group size, ex: -.25' left | ||||
| 14.) Click "Find Zero Angle" | ||||
| 15.) Save and Exit | ||||
| Shooting | ||||
| 1.) Edit environment for current factors or link Kestrel | ||||
| 2.) Put in wind direction/speed and yardage | ||||
| 3.) See firing solution, dial and fire | ||||
| 4.) Verify solution is correct | ||||
| 5.) If solution is incorrect, recheck all parameters, it should be VERY close all the way to 600 (a 1/10th MIL or less) | ||||
| 6.) Fire at 800-1000, to verify | ||||
| 7.) If solution is off at 800-1000 yards, click the box with your solution | ||||
| 8.) Click on "Come up calibration" | ||||
| 9) Click on "Use Total Come up" | ||||
| 10.) Type your needed solution in the "Average box", ex, 10.7 mils | ||||
| 11.) Press calculate for the new Axial Form Factor and Save | ||||
| 12.) Reverify new solution at all distances 300, 600, 800 and 1000 |
Yep work flow looks solid.
So typically we see either linear or non-linear errors. Linear errors are the same at every distance. I'm .2 high at 100, .2 high at 600, and .2 high at 1000. That's a zero issue, either with the app or the optic/shooter.
Non-linear issues are more like perfect at 100, within .1 at 400, .2 low at 800, .4 low at 1000, .7 low at 1200. Those are typically either drag or MV. If you're using a labradar or Garmin you can fairly safely rule out the MV and **Assuming all other inputs are correct** (hint: verify them), you can deduce that the issue is likely the result of a difference between real world drag and calculated drag. That's the point where you pull Axial Form Factor out of your tool box and adjust the Cd curve to match your barrel/load/muzzle device.
I typically recommend writing down the day's conditions (to include wind, even at 100yd), then record MPOI location at 100, 400, 600, 1000, etc... I write what the app told me, and what was actually required to hit. This way I have a record to look back on to verify if I make changes, all ranges match up.
You definitely can have linear and non-linear errors. Good equipment, pre-flight checks, and proper sample size do a lot to cutting the silly/mental and software errors down.
Another note, once you have a profile built and verified, you shouldn't need to adjust it based on location or weather. The caveat to that is MV walk with temperature, but besides that if your zero angle changes or you *think* your form factor changes from day to day, it's a great indication that something is input wrong or you have a mechanical loose end somewhere.
So typically we see either linear or non-linear errors. Linear errors are the same at every distance. I'm .2 high at 100, .2 high at 600, and .2 high at 1000. That's a zero issue, either with the app or the optic/shooter.
Non-linear issues are more like perfect at 100, within .1 at 400, .2 low at 800, .4 low at 1000, .7 low at 1200. Those are typically either drag or MV. If you're using a labradar or Garmin you can fairly safely rule out the MV and **Assuming all other inputs are correct** (hint: verify them), you can deduce that the issue is likely the result of a difference between real world drag and calculated drag. That's the point where you pull Axial Form Factor out of your tool box and adjust the Cd curve to match your barrel/load/muzzle device.
I typically recommend writing down the day's conditions (to include wind, even at 100yd), then record MPOI location at 100, 400, 600, 1000, etc... I write what the app told me, and what was actually required to hit. This way I have a record to look back on to verify if I make changes, all ranges match up.
You definitely can have linear and non-linear errors. Good equipment, pre-flight checks, and proper sample size do a lot to cutting the silly/mental and software errors down.
Another note, once you have a profile built and verified, you shouldn't need to adjust it based on location or weather. The caveat to that is MV walk with temperature, but besides that if your zero angle changes or you *think* your form factor changes from day to day, it's a great indication that something is input wrong or you have a mechanical loose end somewhere.
Thank you for the help. All these parameters in AB produced similar results, to be honest, they were a touch more accurate, but I have grown to love the simplicity of 4DOF and also have a ton of faith in the app properly recognizing the drag curve of my Hornady cartridges. I have a 5500 non-ballistic Kestrel and links and sync quickly with 4DOF and the app is just quicker to use than punching numbers in the Kestrel.
Then I just have to get my EL Ranges to produce the same results which is honestly a very simple process. I love those binos.
Thanks for all the help.
My Kestrel is currently set up to display Temp, Station Pressure, Humidity and Wind Only. I just added elevation today since 4DOF needs that input. Doesn't the elevation in the kestrel use barometric pressure to find this? Is kestrel capable of finding elevation without referencing the pressure or do I just need to always input actual elevation from something like On X (which I did today for a zero angle measurement)
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For most use cases you're fine just putting station pressure. The elevation is for a reference for high angle and very long range. it pulls from a reference table for air density as the bullet gains/loses elevation. For most <1200yd flat fire stuff it's not really a factor.
Ok. Interesting. I will still include it, guess its best to just check On-X or something similar for the input?
I did take the time to go through the entire Zero Angle process today and the results are impressive. After getting my zero angle, I input the parameters/conditions of my last range session and checked it against the hard dope from that session. Its a 13.7" 5.56, so I just checked it out to 800y and it was spot on to the 1/10th MIL without any adjustment to MV or BC. That never happens, with any calculator.
If I have any gripes with the software, I wish Hornady would lock the zero angle settings once you have input them and require you to unlock them to make changes.
Yeah Google Earth or ON-X are both solid for getting actual location elevation.
Glad to hear it's working for you! In my experience that's pretty typical when you give it solid input data. I think a lot of people try to fudge it like you would with G1/G7 calculators and it doesn't respond well to that sort of meddling. The drag data and the dynamic response from the bullet model in the "bullet file" are superior to any other commercial calculator that I'm aware of. If you feed it accurate rifle info (scope over bore, twist) and set up a solid zero with real MV (Garmin) it's a rock-solid file that doesn't require constant changes. Obviously the Hornady guy is going to tout the Hornady program, but they could fire me tomorrow and I'd keep using 4DoF until something better comes along.
Glad to hear it's working for you! In my experience that's pretty typical when you give it solid input data. I think a lot of people try to fudge it like you would with G1/G7 calculators and it doesn't respond well to that sort of meddling. The drag data and the dynamic response from the bullet model in the "bullet file" are superior to any other commercial calculator that I'm aware of. If you feed it accurate rifle info (scope over bore, twist) and set up a solid zero with real MV (Garmin) it's a rock-solid file that doesn't require constant changes. Obviously the Hornady guy is going to tout the Hornady program, but they could fire me tomorrow and I'd keep using 4DoF until something better comes along.
I wanted a 1 pager that I could print off several sheets of on Rite in the Rain paper that encapsulates the 4DOF process along with matching up my Swaros. I tried to only stick with the real world pertinent info that was needed for a good process. Let me know if you think there is any changes needed. Also serves as a good hard copy if apps/systems ever go down or need to be re-entered:
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