Reminds me of Kent State...the crowd provoked much of the violence.
I worked at Camp Pendleton at that time and spoke to a Marine EOD guy (disarms explosive devices) who handled some of the Kent State debris.
He said he found 78 rpm records (about 12" in diameter for the CD generation) that had double-edged razor blades taped around the edges. The disks were Frisbeed at the troops, so if any had hit in an unprotected spot, you'd have been hurting.