We talk a lot about the Kestrel weather meters that are produced by Nielsen-Kellerman. There’s a reason. They’re excellent weather instruments that give the precision shooter all the environmental conditions needed for an accurate firing solution, all in the palm of your hand. There are other meters out there, some at lower prices, but none that I’ve seen match the precision of the Kestrel. If you so desire, you can even purchase models with ballistics engines included on the device. This gives you the added benefit of being able to compute firing solutions from the very device that’s measuring the conditions. However, the ballistics features do come with a price increase!
Kestrel Set Up
This one’s easy. Just leave it alone. The Kestrel ships from the factory in the correct configuration for use in precision shooting sports. That’s not necessarily by design, it just happens to be that their default setup is what we want as long range shooters. In any event, folks may be purchasing one used, or like a lot of people…the temptation to customize and alter default settings can be overwhelming. So we’re going to talk about the two main settings to be concerned about so your Kestrel is set up properly for long distance shooting.
First off, when we talk about these settings, and the intent behind them, we’re discussing the Kestrel 4000 and above series of weather meters. We’ve discussed why at a bare minimum, a precision shooter should purchase a Kestrel 4000. We even wrote an article about purchasing your first Kestrel. If you haven’t read that, now might be a good time. The main thing you’re after with a Kestrel that isn’t a ballistics model, is the current Density Altitude at your shooting position. Density altitude is a hybrid environmental reading that combines individual conditions like temperature, humidity, and barometric pressure. It’s easier to deal with one number than three, and that’s why the emphasis on Density Altitude.
When dealing with barometric pressure there is pressure corrected for sea level, and station pressure. Your weather apps on your phone, and even the pressure given by the weatherman on the news, is given in corrected pressure. It usually looks like 29.92 or fairly close to that. 29.92 is the barometric pressure at sea level. If you’re in the mountains and your Kestrel is telling you the pressure is 29.xx, it’s been set to display corrected pressure. The way to change this is on the barometric pressure screen of the Kestrel.
You want to hit the “-” button to enter the reference altitude. Make sure that it’s set to zero. If it has anything other than zero, it’s correcting the barometric pressure based on that reference altitude. That’s not what you want. You want the live conditions and the current barometric pressure for where you’re shooting. The bullet is going to behave based on what the air density is where it’s fired, not on what a corrected reference pressure should be. By setting the reference altitude to zero, you’re configuring the Kestrel to display station pressure. The barometric pressure for where you’re standing, that is what you want!
Now it’s time to scroll over to the altitude screen on the Kestrel. Just like with barometric pressure, you can alter the reference value. In the altitude screen, the reference value is for pressure. In the altitude screen, you want the reference pressure to be 29.92 for sea level. By doing this you’re saying to the Kestrel, “I want you to read my altitude based off of barometric pressure, and the reference pressure is 29.92 for sea level.”
So if you live in Florida, near sea level, when you check your altitude screen it should be pretty high (Close to 29.92), and it will change constantly as the environmental factors change where you’re standing. If you live in the Rockies, the Kestrel will read your pressure as being lower, around 24.xx, and based on that, it will calculate your altitude to be in the neighborhood of 5000ft.
Take Home Message
Neither the station pressure for the barometric pressure value, or the current altitude, are all that important by themselves. However, you want the Kestrel to be able to accurate measure both of those, because based on those values it will calculate your Density Altitude. The density altitude of your shooting position is the easiest number to work with in terms of generating ballistics charts and figuring out exactly how much adjustment you need on your optic to get the bullet to land on the target at extended ranges. It’s much simpler than manually entering temperature, humidity, altitude, barometric pressure, etc. every time you want to take a shot at something.
Don’t try to change the altitude your Kestrel is calculating manually. Change the reference pressure to 29.92 and the Kestrel will calculate altitude based off the barometric pressure where you’re standing. That number will change, constantly, and the Kestrel will update your altitude based on those changes, constantly. So the altitude number is going to be in flux all the time. That’s okay! Make sure your reference altitude in the barometric pressure screen is set to zero, and that’s all you have to worry about. After that, I wouldn’t even look at the barometric pressure screen or altitude screen anymore unless you’re filling out pages in your logbook.
It’s much easier to work with Density Altitude and if you’ve properly configured your Kestrel according to this article, you’ll be able to trust the Density Altitude number your Kestrel is displaying. This can be kind of confusing, so if you still have questions after reading the article, just drop us a line in the comments and we’ll help get you squared away.