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Being able to get an accurate density altitude has been very valuable for me! I don't see spending the extra money for the applied ballistics version of the kestrel when I can get a beater phone and run the applied ballistics software on that and get bluetooth synchronization of the kestrel data for less money. The phone is not only an easier interface to read and use it also allows for online backup and synchronization of weapon data.
How is the kestrel multi directional with the aid of the wind vane if you can't see the screen ? The only way you can the screen is if the wind is coming from behind you !
Huh, paper? That's that stuff they shove in my mail-box that isn't gun or car parts, right?Indespensible for guys that dont really want to learn how to shoot.
I dont know HOW we EVER hit a target in the 'old days' before Kestrels, ballistic computers and scopes that tell us where to aim. It was crazy! Spray and pray! We actually carried PAPER! With NUMBERS on it! Nuts I tell you, NUTS!
They are great untill the defective batteries they used to issue start to corode out the of poorly designed battery box because of a electronic design flaw and then they offer you a new one at 55% of the price.............
They will never see another cent from me.. Ide use a wind sock and smoke signals before I would buy another.
Temperature is important. But you can do that with a cheap thermometer.
You can get actual altitude from a map or GPS (smart phone).
There is a thread in Basic Marksmanship that discusses baro pressure. It turns out, that over the past year, at the Bang Steel range, baro pressure has accounted for a 0.1 mil change in come up at 1000 yards. So HOW important it is?
Wind speed at the guns location is good, but what about at the target? And mid trajectory? Especially up where the bullet actually flies at mid-trajectory?
Indespensible for guys that dont really want to learn how to shoot.
I dont know HOW we EVER hit a target in the 'old days' before Kestrels, ballistic computers and scopes that tell us where to aim. It was crazy! Spray and pray! We actually carried PAPER! With NUMBERS on it! Nuts I tell you, NUTS!
Funny, there was a small group of people that used to say similar things when RAM air canopies, AAD's and GPS calculated spots started to become the norm.![]()
Its very important if you travel to other locations for comps and or hunting. In some locations, it will change significantly from morning to late in the day and or day to day.
Run the numbers in a ballistics program like JBM.
Taking real life baro pressures from the highest pressure to the lowest pressure over 9 MONTHS, the entire range from lowest to highest pressure was 0.1 mil correction. Or 0.05 from average baro pressure.
Density altitude DOES vary lot over a given day, but due to TEMPERATURE.
Yes, if you shoot in the eye of a hurricane, baro pressure might make a large difference, but for normal weather, it is not a big change.
Run the numbers in a ballistics program like JBM.
Taking real life baro pressures from the highest pressure to the lowest pressure over 9 MONTHS, the entire range from lowest to highest pressure was 0.1 mil correction. Or 0.05 from average baro pressure.
Density altitude DOES vary lot over a given day, but due to TEMPERATURE.
Yes, if you shoot in the eye of a hurricane, baro pressure might make a large difference, but for normal weather, it is not a big change.
That is not necessarily true...
Barometric pressure when used in shooting is also a factor of altitude. So inputting absolute pressure can change it also and have nothing to do with temperature.
In August I zeroed in CO at 5000ft, temp around 80. Traveled to OR at 1000 ft with the same temperature. My dope went from 6.5 mils to 7.2 mils. I use absolute pressure. In JBM as well as I do not correct it. Difference between a recorded pressure of 29.92 vs 24.92 because of the altitude.
Altitude in terms of bullet flight is a feature of barometric pressure which is what he is talking about. When given access to complete data, I use this and not a shortcut as programs were designed with this in mind. DA was added later and is best used as a back up when no software is used. With software I use the actual values from the kestrel. There is a reason it grays out altitude in software.
LowLight's reply in post #33 nails it on the head.
A kestrel or a weatherhawk 350 is a valuable item. A kestrel with Applied Ballistics and BT is nice to have if the price isn't prohibitive for you. You can pick up and old ipod and download a ballistic app for less if it is. The weatherhawk is also a good alternative to a Kestrel if that price is too high for you. it wrks just as well and a review of it can be seen here WeatherHawk WM-350: An Alternative to the Kestrel 4500NV
You are confusing the baro readings. When you get a baro reading from a weather station, it is corrected to sea level. The density altitude correction is covered by the actual physical altitude.
If you take an absolute pressure reading at altitude, you are getting basically a PRESSURE altitude. If you put 24.92 and 5000 feet, BOTH into JBM, you will be WAY off target (unless you uncheck the little box). One or the other.
Yes, pressure changes over altitude, but that is predictable. And JBM takes that into account when you put in the altitude.
Try it, put in 29.92 as the pressure and then change the altitude from 0 feet to 5000 feet.
For my .308 load, 80F, 80% RH at 0 altitude, come up for 1000 yards is 11.3 mils. At 5000 feet (still with pressure set at 29.92) the come up is 9.9 mils.
Notice in JBM, under the Pressure input box, is a check box that says Pressure Is Corrected. If that is checked, it corrects for altitude, and the minor changes in pressure from weather are INSIGNIFICANT.
Yes, you can uncheck that box and input absolute pressure, but then it does not use the Altitude input.
You can use either, but bottom line is, you do not need a pressure reading. But you DO need to know your actual altitude (GPS or map) and Temperature. If you have a pressure reading, you do not need to know your altitude. Would I put out the money for a Kestral to add a pressure reading to my ballistics input? No. I have a GPS.
Baro pressure changes with weather, that is not predictable, but trivial.
For fun, I used your data. I don't know your rifle, so I used my .308 load. If I put in 80F, 80% RH, 5000 feet and 29.92 (with the box checked for corrected pressure), I get a come up at 1000 yards of 9.9 mils. If I put in 80F, 80%RH, and your pressure reading of 24.92 and UNCHECK the pressure box, I get a come up of 10.0 mils. Or a difference of 0.1 mils or 3.6 inches at 1000 yards.
Did you uncheck the box to use absolute pressure instead of corrected pressure?
View attachment 20314
The normal pressure at 5000 feet is about 24.9" of Hg. So putting in 24.92" absolute pressure is close to being the same as 29.92 corrected and 5000 feet.
Air Pressure and Altitude above Sea Level