I prepped a 4lb container of Tannerite and had my neighbor shoot it from 50 yds, Marine and a neighborhood icon. This was about 8 years ago and we are still talking / laughing about it.
50 yds is way too close. It blew everything on my neighbors shooting range to pieces, the target frames and cardboard, and the debris rained down for quite awhile afterwards. We were very lucky nobody was injured.
Started shooting tennis balls filled with Tannerite and duck taped from 100 yds with my evil black rifle after that.
Oh ... and the Sheriff came cruising by soon after the big bang. It was very loud!