It's probably " tannerite "?
I've been to Knob Creek & they used to do the Friday Nite Shoot. Maybe they still do?
It was 55 gal drums partially full of K1 Kerosene/Methanol mix with a bullet excited charge on them. There were at least 15-20 of them down range. As they set them, the big lights were on. Then when ready...lights out.
Ready on the left? Ready on the right?...Commence firing.
As soon as one got hit, the tracers would home in on the rest of them. Of course this is a machine-gun shoot...something to see & hear for sure.
Have been to other shoots that use Tannerite...neat too.
It is mailable without hazmat fees (or it was?) as it comes as a 2 part powder...neither of which by itself is an explosive.
Neat stuff, but not cheap.