Obviously idiot reporters here. If the guy “dismantled the casing and the bullet”, that implies he REMOVED the bullet from the round.
But the police reported people injured by pieces of the casing. That would only occur if the guy had put a full ROUND in the vise, and heated it until ignition of the powder inside the casing occurred.
But since guns and ammo are icky black magic to most reporters. . .
ping - pang - pow!
No, they got it correct, it was a military TRACER round.