Ballistic calculator question?

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Oct 21, 2012
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I recently bought a pair of Leica hdb binoculars. In the process of setting them up with the custom load data on the memory card. When I look at leicas ballistic calculator I notice there is no way to in put atmospheric data. It just says at the bottom that the chart will be based on 30.42 inhg. My question is, do I need to go shooting, gather my data(velocity, atmosph pressure, temp, elev) then take those numbers, put them in shooter and convert them to 30.42inhg, then plug the corrected numbers into the Leica program?
a2a5eha2.jpg
 
30.24 inHg sounds about what sea level would be at. It's just referencing that all data sensed by the Leica is calibrated based upon sea level pressures. You just need to enter the data there that it's asking for and you should be good to go. Obviously check it compared to your real world dope before relying 100% on it. Good luck.

Mike
 
So in my mind, if I chronograph my load at 3000fps at 7,000' elevation. If I put that 3000fps in as my velocity, its going to assume 3000fps at sea level and make the adjustments from that? Or am I over thinking things?
 
If the Leica unit is extrapolating your dope from a referenced sea level pressure value (30.42), that ain't good. You'd have to be zeroing/ chronoing @ sea level for it to jive. And even then, your not using the best data to calculate a correction. Best way to do that is to set altitude values to "o" and measure station pressure at the time of the shot for inputting direct into the ballistic solver. OR, cut all the corners and use Density Altitide in the same fashion. But, I digress...

Since you asked, I think using Shooter App is a good idea to roundabout make it work. If you went into Shooter app and derived a MV @ sea level from your MV & altitude when zeroing, I would indeed use that corrected velocity for inputting into the Leica. Then you would at least be using the Leica program within its limited parameters, if I'm understanding them. Since it stuck you with a fixed pressure, you'll need your corrected MV under those conditions...

Regardless, I'd definitely recommend proving whatever correction that thing is spittin' out to ya!
 
You're over thinking it. And muzzle velocity isn't going to change based on elevation. The bullet hasn't been exposed to the elements long enough at the muzzle to make a difference. Your powder temp sensitivity is the only thing that should change your velocity from one environment to the next.

The picture you posted says the 30.xx inHg pressure is a reference. The ACTUAL displayed drop values are based on your current locations environment.

Basically, plug in you caliber, bullet weight, BC, and sight height and you "should" be good to go! :)

Mike
 
Interesting subject. I thought the G7 rangefinders were the only ones using this type of technology and always wondered why other manufacturers didn't make their own. If Leica is in fact doing this (calculating dope based on REAL situations instead of a constant) that is a big plus.

As a side note, altitude should be substituted with pressure as it is a more accurate measure...i.e. elevation readings are constant but pressure is not, so you could be at 10,000 ft. with a low pressure system sitting on top of you that would demand a lower elevation input than you are really at, whereas if the only thing you are inputting is pressure than there is no need to know elevation. But it looks like that isn't available with the Leica based on your pic.
 
Interesting subject. I thought the G7 rangefinders were the only ones using this type of technology and always wondered why other manufacturers didn't make their own. If Leica is in fact doing this (calculating dope based on REAL situations instead of a constant) that is a big plus.

As a side note, altitude should be substituted with pressure as it is a more accurate measure...i.e. elevation readings are constant but pressure is not, so you could be at 10,000 ft. with a low pressure system sitting on top of you that would demand a lower elevation input than you are really at, whereas if the only thing you are inputting is pressure than there is no need to know elevation. But it looks like that isn't available with the Leica based on your pic.

Good point. As and FYI I actually did some research on pressure swings at a given weather station over a 5 year period and the two extremes were less than .75" inHg over the 5 years. That is hardly enough to make much difference at distances <1000 yards but will definitely start to have an effect at the ELR distances. This is why we always shoot using station pressure, temp, and humidity. Gives really accurate data that matches up good with our dope.

Mike
 
Ballistic AE solver on my iPhone has a weather feature that will accept local current weather data, via cell service or internet connection. Hit a little button on the screen, and all the data populates into the program fields, if service is available. And it accepts and solves with Density Altitude, if you prefer using it.

Still, handy to have along a weather meter like a Kestrel 4500 that spits out calculated DA reading, directly from your shooting position in real time. Referencing DA streamlines the process of factoring environmental conditions to your dope.

My Leica 1600-B offers ballistic bells & whistles that I don't bother with. All I need from my rangefinder, is the range. Those HD-Bs are badazz, but I'd still rather use a stand alone weather meter & proven ballistis solver, rather than clumping too many features into one unit. Sweet binos and tight beam LRF are a nice enough package...enjoy it!
 
You don't need to worry about that. The unit will calculate all of that for you at the time you range it. Just input your load data via the micro sd card, make sure that you have the correct settings in your unit setup, and you should be good to go!
 
You don't need to worry about that. The unit will calculate all of that for you at the time you range it. Just input your load data via the micro sd card, make sure that you have the correct settings in your unit setup, and you should be good to go!

Thats what I thought too. The HDB does it for you at time of range.
 
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