Thread: Pressure is absolute or ft?

What do you use in your balistic program? Do you enable pressure is absolute and don't put in a ft/meter value, just pressure or do you use both, And why? What's best to use, can I just run default settings sub 1000 yards?

I havnt had a play to check the difference yet

if you have a weather station use station or absolute which js the same as you set your reference altitude in your baro readings to zero then you can measure what your actual pressure is where you are shooting.
once you get your head around it its not a problem.
I had my kestrel on on when we drove up the comet the other day and noticed an inch change in hg pressure which made approx .1 mill of difference change of impact at 600 yd.
Temp is a pretty important but humidity nothing
Practice is the name of the game!
I had plenty this weekend with about 70 goats on the deck with nothing closer than 300 and good consistint hits out to 770 with the dirty old 6.5 so all good
Pm me if you want and i can run you through it if you want

IIRC you can't/shouldn't use both as Andy has suggested. Pressure will be the "be all" with respect to ballistics.
Elevation equals pressure (or lack of) and is a function of it (pressure) i.e if you know your pressure (with reference to the current sea level air pressure) you can calculate theoretical elevation. One can't contradict the other? Correct me if Im wrong as Im not 100% sure with FTE.
I do know though, with reference to pressure being "absolute" that will be determining a zero reference. "Absolute" pressure will start in a perfect vacuum with normal sea level pressure being around 1015hPa (1atm). As you ascend air pressure is reduced and is linear against increasing altitude (if all the other variables stay the same).

Normally just chuck me in a round room and tell me to piss in the corner and I am confused.

This has got way out there.
First off, you need cell coverage to use weather station function, no? No coverage where I am so I have never used it.
I just use the Kestrel and manually enter the values off that. Confirm Alt with GPS and its easy peasy.

all i do is use my kestel to give me the station pressure.
if you use station or absolute pressure which from what i can glean is the same you dont need the altitude factor as on shooter you use [pressure is absolute ticked] and then just temperature read in the shade and just a guess for humidity and its all go
I dont mind been corrected if i am wrong but pretty sure i am on the right track as getting the hits right out there

Originally Posted by andyanimal31

I dont mind been corrected if i am wrong but pretty sure i am on the right track as getting the hits right out there

Which at the end of the day is all that really counts

Station pressure Im almost certain will be in absolute pressure. Absolute is just a format with different zero reference.

Today was about 30deg C in Napier or 303deg Kelvin. Same units just different format. Same as gauge and absolute pressures.

So really I need a weather station eg kestrel, or the new Geovids

You can buy suunto watches that give atmospheric readings in both relative and absolute readings, i use mine all the time when LR hunting.

Originally Posted by 7mmsaum

You can buy suunto watches that give atmospheric readings in both relative and absolute readings, i use mine all the time when LR hunting.

Think I got lost there a bit. Shooter has a function that needs coverage to get data and automaticaly applies it?
I dont enable that and enter manually from my Kestrel.
Actual air pressure and temp at your loc, within reason is all that matters, or at least works for me regarding hits.

How muchy for those watches Andrew? Mine just quit with all this moisture around I reckon.

Less then 2 hundy on ebay.com.

You guys are talking about QNE and QNF? Playing with the numbers on my programme i find that baro pressure and altitude (+/- 200ft) dont really alter my POI by stuff all. Before i started using a weather gadget i just input pressure at 1000hpa and was done with it. Temprature on the other hand makes a big difference.

Originally Posted by 7mmsaum

Less then 2 hundy on ebay.com.

Sweet mate I will have a look. Ebay has me on speed dial


Them there is terms used in Aviation Towely

QFE - Pressure measured at the station

QNH - QFE mathmatically reduced/increased to sea level using ISA std figures

QFF - QFE mathmatically reduced/increased to sea level using actual conditions (temperature)

QNE - Emergency pressure setting used for low pressure/high altitude operations. I.E. when the actual pressure setting is off the scale of the altimeter.

So iv never touched the pressure in shooter since i downloaded it and just enable gps so it can use standard pressure For alt?
Obviously the actual measured conditions would be best but i don't have the equip. 600ish would be max for me on a animal and even then only in near perfect conditions.
Is there anything i could or should be doing to improve, not having atmospheric measuring equip?

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this is a good description of how it all works
Barometric Pressure and Ballistic Software