4DOF ZA - Am I doing this right?

[Chukwithak]

New to long range and trying my best to learn my 4DOF kestrel and APP.

If I understand right, I am always suing my station pressure when shooting and my altitude won't really matter if I have my station pressure adjusted right.

To adjust my barometer pressure properly, I input my altitude in the altitude ref under Baro pressure. Note the pressure and reset back to 0 Altitude.

In the altitude setting set my Baro ref to the noted pressure.

This should adjust my altitude numbers based off pressure.

When figuring my ZA, would it be better to just use 0 Altitude and just use station pressure? and use this when raining targets as well? This whole pressure altitude thing is really starting to bug. I plan on using the Kestrel in The Frank in Idaho. Huge elevation and weather changes.

 

[Kestrel Ballistics]

You do not need to adjust anything in the weather side of the meter. The ballistic app knows what info it needs and gets it directly from the sensors. It wants to know the pressure where you are standing, baro and altitude are not used, so no entry is needed.

 

[Chukwithak]

You do not need to adjust anything in the weather side of the meter. The ballistic app knows what info it needs and gets it directly from the sensors. It wants to know the pressure where you are standing, baro and altitude are not used, so no entry is needed.

So when calculating my zero angle, I should set the altitude to zero and the pressure to the station pressure? Essentially always ignore altitude and always use station pressure?

Does altitude and baro pressure essentially try to estimate station pressure and that’s why we don’t use them?

I thought I read something about atmospheric pressure not being on a linear curve.

 

[Kestrel Ballistics]

On the zero angle there is no entry for altitude or pressure because it is not needed. You don't need to enter anything about that. That info is only needed if you want to use the weather side of the meter for purposes other than shooting. For ballistics you enter nothing except target and wind info, the meter uses its sensors for everything else it needs without your input.

 

[Chukwithak]

On the zero angle there is no entry for altitude or pressure because it is not needed. You don't need to enter anything about that. That info is only needed if you want to use the weather side of the meter for purposes other than shooting. For ballistics you enter nothing except target and wind info, the meter uses its sensors for everything else it needs without your input.

Sorry, this is referring to using the IOS app when paired with the Hornady Kestrel. The app asks for both altitude and pressure when finding the ZA.

 

[Kestrel Ballistics]

If this is about the 4DOF app not the Kestrel Link Ballistic app, I don't have the knowledge needed.

 

[Chukwithak]

That’s correct. This is the information the IOS 4DOF asks for. Gets confusing as it wants different information as the Link app and different information as the Kestrel it’s self.

 

[Baron23]

That’s correct. This is the information the IOS 4DOF asks for. Gets confusing as it wants different information as the Link app and different information as the Kestrel it’s self.

If I understand you correctly, perhaps this will help...its a baro to station pressure calculator. Its not an app...just google it and send it to your home screen.

Station Pressure Calculator

www.weather.gov

It does need altitude but there are apps for that in the apple store.

Hope this is somewhat helpful.

 

[JAS-SH]

New to long range and trying my best to learn my 4DOF kestrel and APP.

If I understand right, I am always suing my station pressure when shooting and my altitude won't really matter if I have my station pressure adjusted right.

To adjust my barometer pressure properly, I input my altitude in the altitude ref under Baro pressure. Note the pressure and reset back to 0 Altitude.

In the altitude setting set my Baro ref to the noted pressure.

This should adjust my altitude numbers based off pressure.

When figuring my ZA, would it be better to just use 0 Altitude and just use station pressure? and use this when raining targets as well? This whole pressure altitude thing is really starting to bug. I plan on using the Kestrel in The Frank in Idaho. Huge elevation and weather changes.

You not only need to fill out all of the fields, the information has to be as exact as you can. Use the IOS app and then transfer it to the Kestrel.

Once you have really good environment data for your zero angle the app takes care of the rest. Whenever and wherever you shoot afterwards you just enter current environment data and the app does the rest. That's the beauty of zero angle.

For altitude data you can use the Google Earth app on you phone.

That said, after setting your zero angle you will also need to set up your axial form factor - this is for ranges greater than 5-600 yards. That's basically a bullet drag calculation for your particular rifle at long range (all rifles are slightly different). It's included in the video below.

Links to video:

 

[georgelza]

having scanned through 4Dof a bit, trying to get to know it.
I ran into some questions, barrel twist, it seems to only be in full numbers... we know that 300PRC is like 8.5 ???
Also aware that a left twist and a right twist will behave/react different in a wind from the side. don't see anywhere to specify direction of the twist.
G

 

[6.5SH]

"300 PRC" is a cartridge, whether the barrel is 8, 8.5 or 9 twist is a different matter. Click the numbers and enter your 8.5 directly, you don't have to use the +- slider. As to the right/left twist there isn't a setting for it that I can find, but not an uncommon omission, most apps assume right twist only. Admittedly it is odd given Hornady's own videos on ballistics do go into aerodynamic jump.

 

[georgelza]

... do know the difference, meant 300prc likes/as per Hornady 8.5.

this is admittedly a app interface improvement required I'd say.

thanks, clicked in and changed to 8.5, did try previously, but at the time it did not want to, worked now.

G

 

[JAS-SH]

having scanned through 4Dof a bit, trying to get to know it.
I ran into some questions, barrel twist, it seems to only be in full numbers... we know that 300PRC is like 8.5 ???
Also aware that a left twist and a right twist will behave/react different in a wind from the side. don't see anywhere to specify direction of the twist.
G

You're using the slider for the adjustment. Click on the twist number displayed and enter the exact number.......