Air pressure reality

chindits

WKR
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Feb 25, 2013
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Westslope, CO
I left town two days ago for some high angle shooting. As I was driving I hit my local weather on a Lapua ballistic app just in case I couldn’t get any stations where I was shooting. I had an air pressure reading in the 29 range. All winter my usual readings are in the 21-22 range. So a what the hell moment.

I get about 20-30 miles out of town and check the local weather station option again and I am in the 26 range.

I head up the draw for shooting. I spent nearly 3 hours taking photos and maneuvering around deer and elk trying not to bump them. I’m a few miles into sage but I can still hit cell service because of the aspect of the draw. Definitely not a town cell tower but probably a park tower. Right before first shot I do a local weather station check and I am back to a typical 22 air pressure range. The change in between town the park and shooting area was not over 1000 feet. The weather didn’t change significantly it just warmed up typically.

Questions:

Are all of those air pressure readings accurate ?

How accurate are air pressure readings with range finding binos so equipped as I have never tried the Lapua local weather feature in the middle of no cell service BFE.

Obviously there is a significant difference in elevation scope adjustment between air pressure readings that I was getting that day.
 

hereinaz

WKR
Rokslide Sponsor
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I never felt comfortable with that aspect when traveling in changes of elevation, especially when I did not have service. I always considered BFE service of no use, but that’s only a guess.

Its why I used a cheap weather only Kestrel I bought used for less than $100 for a while. Now, I use my Garmin watch or a ballistic Kestrel.

I trust the pure station pressure sensor in my kestrel and watch. I can also run a Tempe sensor that connects remotely to my Garmin gear.

If you run anything with all in one, like a bino, if you leave it in the sun, the temp on the gadget can get hotter than ambient and screw up your data. I trust my bino as long as it is not overheated.
 

kylem

Lil-Rokslider
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Oct 30, 2016
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North Idaho
I’ve been using density altitude (DA) instead of pressure for the last year or so in the shooter app and it’s way simpler. All you need is temperature, elevation, and an DA chart and you’re good to go.
 
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chindits

WKR
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Westslope, CO
Thanks for the info

As I look at all the scratches on the lenses my old Leica LRF and the realization that it doesn’t slope compensate past 560 meters, I was considering a set of bino RF with weather and ballistics all on board. A separate kestrel weather unit wasn’t really what I was hoping for. If sun on binos RF effects the on board environmental inputs doesn’t it effect the kestrel the same way?
I imagine if I did run a kestrel I would only look at it first thing in the morning and never right before a hunting shot presents itself. How is that normally managed?

Maybe a generation thing, but old military jargon BFE = bum fkn Egypt = absolutely no service in the majority of the backcountry for several days in my hunting areas. Probably not acceptable verbiage anymore.
 
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chindits

WKR
Joined
Feb 25, 2013
Messages
746
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Westslope, CO
I’ve been using density altitude (DA) instead of pressure for the last year or so in the shooter app and it’s way simpler. All you need is temperature, elevation, and an DA chart and you’re good to go.
Having automatic input at the press of a single button and ballistic solution at the same time seems simpler. Is that not possible with RF binos with onboard weather information or are you saying it’s inaccurate. I thought that was there selling point
 

kylem

Lil-Rokslider
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North Idaho
Having automatic input at the press of a single button and ballistic solution at the same time seems simpler. Is that not possible with RF binos with onboard weather information or are you saying it’s inaccurate. I thought that was there selling point
Yup that is definitely simpler I didn’t realize you were talking about a unit with onboard weather info and ballistic calculations. I thought you were talking about manually entering environmental conditions into a ballistic calculator. I’ll end up getting a unit like that when I have the money, but until then I’ll keep using DA in the shooter app and not worry about the air pressure at all.
 

BULLBLASTER

Lil-Rokslider
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Spokane WA
Its pretty easy to get a usable solution without a device to read pressure. For every 1000 feet above sea level subtract 1 from 30 and that is typically close enough for reasonable ranges. Likewise it isnt difficult to get close enough in temp entered.
 

ElPollo

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Aug 31, 2018
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I’ve been using density altitude (DA) instead of pressure for the last year or so in the shooter app and it’s way simpler. All you need is temperature, elevation, and an DA chart and you’re good to go.
I’m with kylem on using DA. Makes life way simpler. You can set up most ballistic apps to use it. Here is a link to directions @Formidilosus posted on setting up the shooter app to use DA.


Edit: Helps if I remember to add the link.
 

ElPollo

WKR
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Aug 31, 2018
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I’m with kylem on using DA. Makes life way simpler. You can set up most ballistic apps to use it. Here is a link to directions @Formidilosus posted on setting up the shooter app to use DA.


Edit: Helps if I remember to add the link.
I went in and looked at the version of Shooter on my iPhone which I pulled down recently and those directions don’t work. There isn’t an option to get into setting to specify DA. However, while I was down that rabbit hole I did some playing around with it. In the newer version, it seems to default to DA if you leave your pressure empty and enter the temp and elevation.
 
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chindits

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Westslope, CO
Its pretty easy to get a usable solution without a device to read pressure. For every 1000 feet above sea level subtract 1 from 30 and that is typically close enough for reasonable ranges. Likewise it isnt difficult to get close enough in temp entered.
30-7.8=22.2 pretty close today

IMG_4890.png
 
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