In my article about the 2013 So Cal PRC I mentioned that I won a Kestrel 4500 featuring the Horus ballistic calculator for my 8th place finish. I have been using a regular Kestrel 4500 personal weather station in conjunction with the ballistic program Shooter. The Kestrel 4500 allows me to input the most accurate and current atmospheric information into the ballistic program. Using the information from the Kestrel gives the ballistic program the proper information to accurately predict my bullets drop and deflection.
The Horus program in the Kestrel features a profile library where you can store multiple profiles for different loads or cartridges. You can also set up to 5 ranges and actively run them. The program will continually update the dope for the selected ranges based on data detected by the sensors from the Kestrel. I have been using the set up here in Las Vegas and so far it has been very accurate out to a range of 686 yards (I plan on testing at farther ranges soon). For ranges you are not actively running you can pull up the range card feature and view drop and deflection (as well as other information) in 5 yard increments.
One thing I like about “Shooter” is the two different condition inputs, one for the conditions while the rifle was zeroed and the other for the conditions you are currently shooting in. The program will take into account the conditions while you zeroed the rifle and will calculate that into its predictions. The Horus program does not have this feature so I feel it is best utilized when you can zero the morning of a match or even the day before. The Horus program utilizes G1 drag models and allows you to enter different ballistic coefficients to account for the gradual slowing of the projectile. Right now I am using my Barnes 6.5mm 140 profile with a G1 BC of 0.586 and it has been very accurate to a range of 644 yards. During the January Las Vegas Precision Tactical Rifle match I managed a 2nd place finish using the dope from the Kestrel/Horus. That was my first time using the 6.5mm 140 grain Barnes Match Burner in competition. Before the match I had only worked on load development and had very limited hard dope with the new load. The Kestrel/Horus combo helped make the transition to the Barnes Match Burners easy.
Some of the units features I have yet to use, one of them is the programs ability to account for the Coriolis Effect on a bullets path. By using the internal compass in the Kestrel (you must calibrate it prior to use) you can hold the Kestrel in the direction of a target and “capture” the direction information. You can also hold the Kestrel into the wind and capture the wind speed and direction information. The program will take a 5 second sample and give you the wind information for the low and high speed detected during that duration (the deflection prediction accounts for both speed and direction). I have been meaning to utilize this feature but honestly I forget it has that capability.
I have found Kestrel units to be relatively durable. I treat it like a sensitive instrument but do not baby it much beyond that. It rides in my kit with the rest of my gear and sometimes the bag and equipment within it have to serve double duty as a support or sometimes a blast barrier. The only thing I have personally seen take out a Kestrel has been the Las Vegas sun amplified by a truck windshield. The unit got hot enough that the batteries inside exploded. We were able to revive the Kestrel down the road and surprisingly after restoring the factory setting it is now working (with new batteries of course).
I am very excited to add this piece of equipment to my kit. The weather station/ballistic calculator are a great combination and it means I do not have to rely on Shooter or hard dope alone. The Kestrel/Horus program should be very helpful when out hunting in Northern Nevada or shooting away matches in unfamiliar conditions. I still have plenty of testing to do and have been checking the information from the Horus program against Shooter and my hard dope. To date I have been very pleased with the results. I will do my best to keep everyone updated on how things progress. I plan on testing the combination at longer ranges and utilizing some of the other functions of the unit.