In the Czech Republic is energy of air gun pellet limited to 16 Joule by the law. This fact has been reflected by HFT rules as well, so any shooter whose air gun exceeds that limit may be disqualified from the competition. It would be also unfair towards other competitors to shoot with higher power because it would give the shooter an advantage of more favorable ballistic curve, so he/she would be able to accept larger errors in both wind and distance assessments. Sure everybody tries to set his air gun’s power to allow maximum for optimizing the ballistic curve without being disqualified from competition.
In order to fulfill all requirements the air gun has to be set properly. Shooting chronograph is essential tool for all shooters who take shooting seriously and who want to be sure that their air guns perform consistently with a properly set power.
Kinetic energy can be calculated using formula Ek=1/2mv2, where m represents the pellet’s weight and v represents its speed. The weight is known as it is stated directly on the pack. Bigger problem arises when we want to know the pellet’s speed. For measuring the pellet’s speed we use shooting chronograph which measures a time the pellet needs to pass the distance between two light-sensors. In fact, shooting chronograph is just a stopwatch capable to measure the time interval between shadowing the first and then the second light sensor. We know the distance between sensors so after getting also the time we can calculate speed by using a formula v=d/t. But ordinary shooter does not need to care about this because AirChrony Mk3 performs all those calculations automatically. From the user’s point of view it works simple - just turn the tool on then make a shot through the measurement gates.
Air Chrony Mk3 visual design comes out from the previous model, but the whole construction has been significantly reinforced having also double plated sides. I saw a lot of various chronographs during various occasions, some of them I even used, so I can tell by my own experience that there was never so resistant chronograph here before. Shooting chronograph, as indicated by the term itself, is dedicated to measure speed of bullets, so people use to shoot through it. You need really resistant chronograph especially if you use it on competitions where hundreds of various competitors take measurements by shooting through it. Recent chronographs are usually made of plastic, so despite great vigilance it is no problem to destroy them just by a one unlucky hit. I remember even two World Championships where pellet-speed measurement had to be canceled due to destructed chronographs. But now, finally, I can see a chronograph which I am not afraid to let it be used by other contestants. I am not claiming that you can shoot into the Mk3 without worry, not at all. However, the Mk3 withstands a hit every once in a while without problems, except from hitting directly the display. I mean hit by ordinary diabolo with maximum energy of 16 J, of course. The measurement gate’s front window is large enough (56 x 59 x 75 mm) so you can shoot through it even from a larger distance, for instance when collecting data for Ballistic Coefficient calculation, providing you are shooting appropriately carefully.
The whole chronograph is protected by resistant painting in black.
The largest difference in design can be found inside the box. Also the way of measurement has been significantly changed as light sensors now measure beams reflected by the opposite glossy surface. Chronograph has in-built infra-red LEDs as a light source for measuring in poor lighting conditions or even in a complete darkness.
At first glance we are attracted by three-row display showing essential data.
There is a sliding on/off switch situated below the display and also three push-buttons for menu control. AirChrony Mk3 provides all functions like most of the chronographs on the market, so using a menu control we can read speed, kinetic energy, pellet’s weight, number of shots, average speed, average energy, maximal speed, minimal speed, standard deviation or cadence. In contrast to previous model, with Mk3 can user freely switch between metric or imperial units, turn on/off backlight of display or select a language (8 languages available as a standard). Weight of the pellet can be easily set in a range between 0,01 and 65 grams with 0,01 gram steps. You can set the weight declared by the pellet’s manufacturer or you can weigh the pellet yourself.
Mk3 can record up to 250 individual shots, in range between 2 and 2000 m/s each.
Great message for unexperienced users is the fact that AirChrony manufacturer has created video-tutorials. They are easily accessible on YouTube channel at https://www.youtube.com/channel/UCjJzTyXm7ST_y2l0w95WlIQ/videos and provide materials even for very beginners.
Chronograph is powered by three standard AAA batteries for longer running time. It can run up to 7 hours (with high-quality batteries even longer). Battery holder is inside the box in an opening closed by a metal plate attached to the box by magnets. Chronograph can be powered from external power supply, in such case batteries are not necessary.
First of all I was curious how Mk3 will manage measurement accuracy and repeatability. I performed a classical test when I placed two chronographs in line and made shots through both of them at the same time. After 20 shots each chronograph recorded 20 measurements and the speed recorded by the more distant one was regularly lower by few tenth of m/s in comparison to the nearer one. Reliability and repeatability belongs to the strong features of AirChrony since Mk1.
Human is a mistrustful being and because we use chronographs on HFT competitions where tenths of m/s may lead to decision about disqualification, I wanted to know if measured data corresponds to reality and if it is not different from the real speed of pellet. This question has been clearly answered as AirChrony Mk3 has passed in TÜV SÜD test with the result proving that Mk3 is comparable to their own calibration device (the difference was only in hundredths of m/s).
Chronograph has an output for connection to the computer. Unlike previous models the Mk3 utilizes standard USB port (whoopee!), so you do not need any strange converters anymore, normal USB cable for mobile phone would be enough. Software is a big strength of this new model. Results can be shown on large monitor immediately or saved to computer for future processing in creation of graphs and statistics. Software is upgraded by manufacturer with improvements and new functionalities quit often. Software can be downloaded from manufacturer’s home page for free.
There are four rubber pads mounted on a bottom plate providing stability with anti-slippery function on slippy surfaces. But more important feature is a ¼ UNF threat which I missed on previous models.
Now we can attach chronograph to any standard tripod and easily adjust requested height or angle.
I cannot resist performing a small test about what is Mk3 capable of. After a short thinking I came upon a solution: just lay chronograph down on the ground and simply drop pellet into measure gates from my hand. I must say I was bowled over when I found out that Mk3 can measure speed of freely dropped pellet without any problem.
As an option, Air Chrony Mk3 can be purchased with very practical and clever case made of Cordura fabric which protects chronograph during transportation. After lowering front and back sides it can be also hanged from the tree and used as a support instead of tripod. The case may be delivered in two variants as black colored or in camouflage.
Mk3 is today the most modern chronograph on the market. It combines sturdy but compact design with very high accuracy. Keen support from manufacturer on internet is a big advantage. There are video-tutorials available so you can learn how to properly use and control your chronograph. For graphs and statistics fans the Mk3 brings easy connection to computer and possibility to process and evaluate transferred data in spreadsheet.
One interesting thing provided as a conclusion. Besides the Czech Shooting Association is AirChrony Mk3 used as an official chronograph also by Portuguese association and will be utilized on upcoming WM FT 2016.
Taken with the permission of the author from www.fieldtarget.cz