Global Measurement Solutions Method Validation Projectile Velocity Van Zyl Koegelenberg Global Measurement Solutions

External Ballistics Repeatability Problem Knowing what happens once a round leaves the muzzle Measuring and duplicating claims Event occurred, is this possible? Mathematical conclusions ie Energy of projectile, Retardation, etc 9mm, 10 shots, same batch, same test session Repeatability Problem No two projectile will ever perform the same Each shot is unique Everything changes during the trajectory Velocity, Acceleration Environment ie. Air density, Speed of sound, Temperature Van Zyl Koegelenberg Global Measurement Solutions

Methods available Chronograph Doppler Radar Low cost Easy to use Can measure at a specific position, where placed Close range Doppler Radar High Cost Not easy to use Can measure velocity at a any position in trajectory Long range Both are used, it was needed to verify that the everyday use of chronographs are acceptable Need to verify between Calibration cycles that the Chrono Graphs are in working order Van Zyl Koegelenberg Global Measurement Solutions

Chronograph method Principle of operation Projectile Start Stop t0 t1 Known Distance ie 1m Average Velocity Displayed = Distance/Time = 1/Time Van Zyl Koegelenberg Global Measurement Solutions

Doppler Radar Technology Projectile Track Van Zyl Koegelenberg Global Measurement Solutions

Doppler Radar Technology Van Zyl Koegelenberg Global Measurement Solutions

Comparisons between Radars Inter-laboratory comparison / Different products, same model / Different products, different models / Same shots, different operators Dop A Dop B Var m/s Var% 876.836 876.865 -0.029 0.00% 870 870.562 -0.562 -0.06% 864.303 864.221 0.082 0.01% 857.962 857.529 0.433 0.05% 881.827 881.706 0.121 875.593 875.625 -0.032 869.303 869.072 0.231 0.03% 862.947 862.482 0.465 879.578 879.795 -0.217 -0.02% 872.591 872.692 -0.101 -0.01% 865.547 865.62 -0.073 858.453 858.593 -0.14 325.746 325.971 -0.225 -0.07% 312.299 312.438 -0.139 -0.04% 302.79 302.982 -0.192 295.911 295.945 -0.034 289.956 289.536 0.42 0.14% 323.809 323.684 0.125 0.04% 311.355 311.207 0.148 302.331 302.369 -0.038 295.511 295.884 -0.373 -0.13% 289.305 290.064 -0.759 -0.26% Average -0.04041 SDEV 0.292403 0.08% The Average % Variance at -0.01% We found the method reliable and repeatable Van Zyl Koegelenberg Global Measurement Solutions

Comparing Methods Velocity displayed Projectile Velocity obtained on Doppler system Measured at x meter Two methods, two technologies, same projectile at same time, same conditions Van Zyl Koegelenberg Global Measurement Solutions

Using both methods to verify Chronographs Avg Avg % SDEV m/s SDEV % Min % Max % No of Points 0.131724 0.08% 1.995433 0.31% -1.72% 0.83% 187 Place Chronograph at measured distance Fire shots Measure velocity at same distance with Doppler Collecting all information from all tests from all products Avg Avg % SDEV m/s SDEV % Min % Max % No of Points 0.14481 0.03% 2.229302 0.43% -1.72% 2.67% 801 Done for this presentation The specified accuracy of the Chronographs are 0.5% Van Zyl Koegelenberg Global Measurement Solutions

Practical conclusion 8 Joules of energy is treated as a “Licence” or control is required Research show that ie 8 Joules is required to penetrate the skin, so 8J the critical level Eye ball can be removed with 12 Joules, etc etc Hence accuracy is required at all times Need to prove that the methods used are accurate and repeatable Suppliers of Forensic products protect their technologies with limited available information Look at results from practical angle 𝐸𝑛𝑒𝑟𝑔𝑦 𝐾𝑖𝑛𝑒𝑡𝑖𝑐 = 1 2 ×𝑚𝑎𝑠𝑠 × 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 2 =0.5×𝑚0.00745 × 0.14481 2 Average measured variance on velocity is 0.14481 m/s On a 115 grain (7.45g) 9mm round, that is 0.0781 mJ The specified accuracy of the Chronographs are 0.5% We found both methods repeatable We found the chronographs within specifications for everyday use Chronographs are now verified at least once every 3 months, more work required on the stats Van Zyl Koegelenberg Global Measurement Solutions

Thank you Conclusion Validated Doppler Technology Validated Chrono Graph Utilising both methods in gaining trust as a repeatable solution Use the test data elsewhere ie. Trajectory prediction Thank you Van Zyl Koegelenberg Global Measurement Solutions