Herb Husker replied at another forum to John Corbett's questions about his analysis of the possibility that a bullet fragment from the Z-313 head shot wounded James Tague:
The main question about fragment velocity is a good one. Fragment velocity is one that couldn’t be looked up but had to be calculated. The model to do this was based on solving equations of motion for projectile travel, in this case bullet fragments, in horizontal and vertical directions. A decent estimate on the fragment ballistic coefficients was necessary to determine velocity retardation during flight.
The basis constants in the attached were looked up as the best values I could find for the necessary variables at play here. These were not totally arbitrary, but the best values I could find. The modeling then calculated the fragment velocities by using the solver function. The arbitrary value here was the starting input value for the fragment velocity. The model iterated that velocity value, while using the non-arbitrary other constants, to find out what velocity would solve the equation of motion for the given curb distance. Net, how fast would it have to be going to reach the curb by Tague under such conditions. Some variations on key variables were also looked at for a sensitivity analysis.
The two main base cases evaluated predicted 846 ft/sec and 888 ft/sec, so for the fragment exiting the limo something abound 850 ft/sec appeared to be a good estimate.
The surprising thing out of this analysis was at the terminal end of the trajectory at the curb strike, the trajectory was close to vertical, and the velocity was essentially the terminal velocity of a fragment having a poor ballistic coefficient.
Another surprising thing was a test I ran in my basement to test the general concept with a projectile's having a similar striking energy. I found that a vertical shearing curb strike could chip off shards off a concrete block and strike me in the leg while I was standing a few feet away.
The summary of the work here describes this in more detail.
https://drive.google.com/file/d/1CcnCy17Hwqqw3zBCK7ls8peA3DxmVzhk/view?fbclid=IwY2xjawUNquVwZG9mAWV4dG4DYWVtAjEwAGJyaWQRMUZjZ2dObDk1emhHSW1NYUdzcnRjBmFwcF9pZBAyMjIwMzkxNzg4MjAwODkyAAEeJG8GSrUlD4T-8jA5RY48A7vDLpCLmGyuncXSge0ythorYqh2qFYB3U8Bjl0_aem_fv7vr94a-tvdXN6B1TxRvQ&pli=1[I was unable to copy-paste here a chart in that's in Huskr's reply, but the same chart is on page 3 of his study]
