The need for speed
Rod Pascoe tests the Bulletseeker chronograph
To anyone who reloads their own ammunition a chronograph is an essential piece of kit for precise load development. One of the fundamental measurements of bullet performance is muzzle velocity and the way a particular projectile behaves at a particular speed can be plotted against others as the powder charge, bullet weight, seating depth and so on are altered to achieve the required precision.
In a conventional light-barrier chronograph system, units need to align between firearm and target at a short distance in front of the muzzle. This can take some time to set up and the equipment can suffer from errors if the bullet’s path isn’t tracked correctly due to lighting and other environmental factors.
In more recent times radar technologies have been enhanced to the point where automotive, military, aviation, meteorology, law enforcement and other industries and organisations use a single directional radar beam system to observe and measure moving objects, similar to the rotating radar we’d commonly see on a ship’s mast or at airports.
Examples of everyday use of this technology, known as Doppler radar, is the roadside sign telling drivers how fast they’re going through a school zone or roadworks and the adaptive cruise control systems in some cars. But not only is this technology used for catching speeding drivers, the velocity of a speeding bullet can also be accurately measured.
Australian Shooter was supplied with one of the new-generation radar systems by Sydney-based firearm accessory specialist Accurise. The Bulletseeker Mach4 chronograph is unlike other similar systems in that it’s small enough to fit directly to a rifle, pistol or shotgun barrel with the supplied fitting or alternatively, for firearms already equipped with a Weaver-style or Picatinny rail, the Bulletseeker can be mounted in alignment with the barrel.
The manufacturer does make several suggestions about proper mounting for best results including working with muzzle brakes fitted to barrels. They state: “Explosive ammunition creates a muzzle cloud from hot gases and metallic abrasion. This cloud of plasma and metal splinters is electrically conductive. It can interfere with the radar waves and wipe out the signal. We have tested different muzzle brakes and those with a guided gas jet such as a star or spiral shape allow the radar signal to pass through very well.” They further suggest (and I discovered) that with or without a muzzle brake, trial and error is needed to get the sensor in the optimum position.
The unit is made in Europe by a collaboration of engineers, programmers and mathematicians from half-a-dozen countries. For the technically minded, the heart of the system is a 120 GHz radar chip made in Germany and this extremely high frequency (or short wavelength of 2.5mm) means that unlike light-barrier chronographs which measure the bullet passing just two detectors, the bullet is detected up to 1000 times in the first metre of travel from the muzzle. The system is advertised to measure bullet speeds up to 4000 feet per second.
As part of the system you simply download the Bulletseeker app to your phone or tablet which is then paired to the Bulletseeker sensor. Once the sensor is fitted to a firearm and powered up with Bluetooth connection established, the app is where the user customises the session for the particular test being performed, whether comparing loads for development or simply confirming velocity of a favourite load. Also, in some pistol shooting competitions a minimum ‘power factor’ (bullet weight multiplied by velocity) has to be achieved.
The system is very intuitive and learning the different parameters becomes straightforward. User profile can also be set as to whether metric or imperial units are used to record velocity, energy and mass. The ability to document details such as atmospheric conditions, bullet and powder brand, type and weight along with other notes, provides a complete tally of the day’s testing, time-stamped and retrievable for future reference.
A continuous log file is kept with minimum, maximum and average readings calculated in real time which can also be exported to an Excel spreadsheet. Your phone or tablet screen will display visual depictions and graphs of bullet performance, while an online manual will guide you through the many parameters available either at time of firing or for later analysis.
At the range using both pistol and rifle loads the system worked as advertised. Mounting the sensor to the rail of a pistol was straightforward and correct alignment of the radar beam was automatic, being mindful of the narrow radar beam of 22 degrees. Mounting on or beside rifle barrels was, as stated earlier, a bit hit and miss but once established the Bulletseeker didn’t skip a beat. I found the entire system performed well after working out the mounting set-up.
The price of the unit is comparable with similar radar chronographs at around the $1400 mark at time of writing, though check with Accurise for the latest on price and availability at accurise.com.au. And while you’re there, peruse their other accessories for the precision rifle shooter.