Bullets Do Not Melt Polyester Fibers

The CIB Forensic Report [CIB1] states that the fibers near the entrance holes exhibited signs of melting, a thermal damage. The melting of the fibers on Chen's jacket could not have been caused by powder residues: The CIB found no gunshot residue on Chen's jacket, and the Lee Report confirms the absence of powder residue.

On the other hand, the contact time of the lead bullet with Chen's jacket, which had an impact velocity between 150 m/sec and 200 m/sec, is approximately 0.1 millisecond. For the same reason that the lead bullet could not have caused burn injury to Chen's abdomen, it could not have caused the polyester fibers on Chen's jacket to melt. The amount of heat that was transmitted from a bullet with surface temperature at most $200\tccentigrade$ in 0.0001 second was far too small to melt the polyester fibers. In addition, polyester fiber has a softening point of $238$- $240\tccentigrade$, and a melting point of $255$- $260\tccentigrade$. It is much more difficult to melt polyester fibers than to inflict thermal injury on skin tissues.

Conclusion Unless the CIB made a basic error concerning the melting of the fibers near the bullet entrance hole on Chen's jacket, the 319 incident did not happen as purported.