Good grief, all the red tape they must go through just to poke a few holes in a murdering SOB.... and of course NPR has to gripe about everything (projectiles bouncing and hitting witnesses behind bullet proof glass and inhaling poisonous gun smoke)...
Just tie the scum up to a tree (why damage a metal chair) and make a good backstop.
Or course, the manual they linked only has a bunch of "refer to other manuals" for stuff I want to know, like what caliber and rifle they will be using....