I have a question about calculating zero angle on the Hornady Kestrel. I have used the 4dof app on my iPhone quite a bit and am familiar with calculating zero angle on it. The app allows you to input the "impact height" and the "impact windage" during the "find zero angle" function. And the app takes into account the impact windage of your zero and accounts for that when giving you windage corrections. However, in the Hornady Kestrel, it only allows you to input the "impact height". I don't see anywhere in the Kestrel that allows you to input "impact windage". I was wondering if I am overlooking it. Thank you for your help and Happy Thanksgiving!!
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Zero angle on app vs Hornady Kestrel
- Thread starter oniak
- Start date
I don't Kestrel in front of me to play with but if you know your zero angle then I would just input the value in the Kestrel app/Kestrel. Plus its faster to input the values on the phone to calculate zero angle value.
Probably a dumb question but........ If your rangefinder gives you an adjusted yardage based on the amount of incline or decline you have, do you still need to determine your zero angle value?
Yes or use the traditional 100 yard zero method. Zero angle value has no correlation with angle adjusted yardage.
Zero angle value refer to the relationship of your scope to barrel. By entering the requested values, the solver is calculating the degree value of the interior A angle. That value should never change unless you move/change your barrel or scope. Since you are find the actual angel of the barrel to scope relationship, not just POI at 100 yards, you’ll never have to rezero you rifle for ammo or load changes as the app will make the correction once you enter MV and bullet selection. I’ll see if I can find the graphic that does a better job at illustrating it.
The head ballistision at hornady talks about running two different loads/bullets at matches without issues. I personally have not tired this but hope to on the next range trip.
I have personally ran 2 different loads at matches with no trouble using zero angle. Definitely a bonus not having to re-zero the rifle and being able to clone the profile and simply update bullet/speed.
I don’t know for sure, but I think the impact windage feature on 4dof phone app came out after the Kestrel was released. I bet they can update the app a lot quicker/easier than kestrel can. Not sure if this is the case but a possibility.
I don’t know for sure, but I think the impact windage feature on 4dof phone app came out after the Kestrel was released. I bet they can update the app a lot quicker/easier than kestrel can. Not sure if this is the case but a possibility.
It would be great if Kestrel would do some Zoom courses on the 4Dof version. Their ones for the AB has been excellent. To the point I keep thinking of getting rid of the hornady for the AB due to the support and education through their courses on it.
They did one in October and it was great. I suggested they do another one or post a recording somewhere. The hornady can function just like the AB but the zero angle and axial form factor do take some reading up on grasp how they work. Just wish they had a larger bullet library. I get they hope to push you toward their product but I will be willing to pay for an expanded library.
The Windage Offset in the App came out after the Kestrel release so the Kestrel version doesn't have windage offset (yet). What I used to do (kestrel or app) was shoot my zero angle shots at whatever yard line, calculate the elevation offset for zero angle, then with the zero angle and environmental info entered, re-run the calculation to determine how much windage was from wind/spin and how much was zero error then correct for it and/or note how much it was.
I would not use 4DoF with angle-adusted ranges. You will find errors that get worse and worse the farther and/or more extreme angle you shoot. The angle cosine method that the LRF is using doesn't take into account the drag or ToF of the difference in yardage between true distance and 'gravity distance'.
Zero angle is not related to incline/decline shooting, either. It's a separate topic. Most folks use a 100 or 200yd zero RANGE where they zero at 100yd and ASSUME conditions in various altitudes/environments will be similar enough that the 100yd zero will always be close enough. All of the ballistic solvers assume the 100yd zero you input is exact so any small errors in 100yd zero as conditions change will manifest as larger errors the further down range you go.
Zero ANGLE takes into account the distance you are shooting, THAT DAY'S environmental conditions, and small errors in zero (hitting .15" high of POA for example), then back-calculates the angular relationship between your rifle's barrel and your scope's crosshairs with the scope set at "0". That angle is much less sensitive to change with changes in temp, baro pressure, altitude, etc... than a 100yd zero range.
Either method will work (although zero angle tends to be more robust in general) for incline/decline shooting.
Ledzep:
Wow! I thought using a Kestrel was suppose to be easier than using my iphone and StrelokPro or Shooter. So if I understand your comments above, I should use the actual yardage provided by my rangefinder but do the extra steps to determine my rifle/scope's angular relationship? I would have thought that the software, whether on the phone or the Kestrel, would use the height of the scope to determine the angle without all this extra work on the user's end.
Wow! I thought using a Kestrel was suppose to be easier than using my iphone and StrelokPro or Shooter. So if I understand your comments above, I should use the actual yardage provided by my rangefinder but do the extra steps to determine my rifle/scope's angular relationship? I would have thought that the software, whether on the phone or the Kestrel, would use the height of the scope to determine the angle without all this extra work on the user's end.
I agree, the Applied Ballistics Kestrel seems much more intuitive to me for that reason.
Before I discuss this any further I want to make sure we separate two completely different subjects.
1) Zero range vs. Zero angle
2) Incline/Decline of the shot
1- Zero range is the yard line you zero at, and then you maintain the ASSUMPTION that your XXX yd zero range will always be spot-on. It's an ASSUMPTION because it moves around. Changing temp, baro pressure, wind, etc... Will all cause deviations in your zero range. Some are small, some are big.
OR use the zero angle feature to determine the angular relationship between your barrel and your scope. Day-to-day, and especially location-to-location changes in environmental conditions will have a drastically smaller effect on the angular relationship between your optic and your barrel than what will happen with an assumed-correct 100yd zero.
The ballistic solver, when using zero RANGE assumes that your 100yd zero is PERFECT. It often isn't, though, and the small errors that happen at 100yd then propagate over longer distances.
2) Shooting up hill/down hill using the compensated range your LRF gives you is wrong because of this picture below. Yes, the cosine angle compensation will account correctly for the gravity over the shot, but it will NOT account for the extra drag marked by the orange line, nor the extra time of flight.
1) Zero range vs. Zero angle
2) Incline/Decline of the shot
1- Zero range is the yard line you zero at, and then you maintain the ASSUMPTION that your XXX yd zero range will always be spot-on. It's an ASSUMPTION because it moves around. Changing temp, baro pressure, wind, etc... Will all cause deviations in your zero range. Some are small, some are big.
OR use the zero angle feature to determine the angular relationship between your barrel and your scope. Day-to-day, and especially location-to-location changes in environmental conditions will have a drastically smaller effect on the angular relationship between your optic and your barrel than what will happen with an assumed-correct 100yd zero.
The ballistic solver, when using zero RANGE assumes that your 100yd zero is PERFECT. It often isn't, though, and the small errors that happen at 100yd then propagate over longer distances.
2) Shooting up hill/down hill using the compensated range your LRF gives you is wrong because of this picture below. Yes, the cosine angle compensation will account correctly for the gravity over the shot, but it will NOT account for the extra drag marked by the orange line, nor the extra time of flight.
You can still use zero range (100yd zero, for example) with 4 DoF just the same as any other ballistic solver. However, with 4DoF you also have the extra option to use zero angle if you want to.
Note that the zero angle is the same in both sets of conditions, but the zero range is slightly different.
ETA: Green line is the bore axis
If I may, entering the values into the Hornady Kestrel is best accomplished using the Kestrel Link Ballistics app. You'll be able to enter all the pertinent information and send it to the Kestrel. This is the best method, the most easy method anyway, that we've used.
@Ledzep fantastic explanations BTW, cheers!
@Ledzep fantastic explanations BTW, cheers!
You are not. The Kestrel release did not have that feature. The trick is to do the Zero angle in the phone app, and then transfer it to the Kestrel.
Here's the skinny: The app starts with the premise that you will start by using the best, repeatable Zero "Range" you can get at say 100 yards. At 100 yards, in most scopes your nonadjustable margin of error is .36 and .25 inches in Mil and MOA respectively. That's really what the windage is for. Those errors can get very large at distance. The app also asks you for your environmental conditions.
Done correctly, the app will then take everything you input into the setup to generate all future solutions. No re-zero needed after that. All you need is the new environmental conditions and the distance. It does the rest.
That said, at ranges longer than say 500 yards it will not take into account the variations in drag factor for your specific rifle, 4DOF gets away from BC, using drag factor instead. For that you have to shoot a group at say 600 yards and enter an adjustment to the the coaxial factor. It's only then that the Zero angle solution will get very accurate at long range. If you are using a bullet that is not in the 4DOF database then you will have to use a manual BC correction (change the BC number) for longer ranges.
Obiously, all of this will work for just One Bullet/load combination. If you change loads it will not.
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