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kman
02-04-2008, 03:20 PM
has any one here had any experience with the kestrel 4000 ,what does all this imformation tell a shooter as far as the density altitude, humidity ,and so forth im trying to figure out which one has the most bearing on group size,andwhich one makes the group move up or down or left or right or open up any imformation will be of help

thanks in advance

bsl135
02-04-2008, 04:32 PM
Kman,
There are two fundamental uses for a tool like the Kestrel in shooting.

The first use is in determining the atmospheric conditions (pressure, temperature and humidity) so they can be input into a ballistics computer. The computer uses the information to calculate air density, and that's used to determine time of flight, velocity decay, and most importantly, drop. The denser the air, the more drag, velocity decay, and drop. If you don't have the ability to calculate trajectories in the field (laptop or palm pilot) then it doesn't make any sense to have a Kestrel in the field (for this application). If you're basing your drop at range from pre-calculated tables that were run for some set of atmospheric conditions, it's not practical to make adjustments to those numbers in the field based on the Kestrel readings. The trajectories must be run with the actual, real time inputs. This application for a Kestrel is of use to long range hunting or tactical style shooting. There is little utility for the Kestrel in known distance target shooting, at least not for calculating drop due to air properties.

The second use for the Kestrel has been recently discussed at length on other threads on this forum. Just look at the threads on barrel tuners in the centerfire board. Basically, the Kestrel is used to determine density altitude so the barrel tuner can be adjusted properly. This is an entirely different use as the first application I described above.

-Bryan

Edited to add:
I just thought of a third use, something I do with mine.
In long range shooting, it's important to be able to judge the wind speed and direction. When I walk my dog thru the fields, I'll take my Kestrel. I'll periodically stop and make my best guess of the wind speed, then measure the wind speed and see how close my guess is. It's a way to calibrate your judgment of wind speed.