just found out the composition materials for the Z16, Z16A, Z17, and Z17A Spark Hits by de lamare in the usa,
not surprisingly - Zirconium / Potassium perchlorate composition
Appearance - Bead of dark grey powder
deposited onto a plastic resin base and
sealed in a clear lacquer membrane. The
bead encloses a resistance wire in contact
with insulated connecting wires
not surprisingly you don't need much for a great spark effect that outperforms Titanium or Aluminium sparks hands down, for a theatrical bullet hits metal spark effect (obviously not a realistic effect, but a visually impressive film effect)