My CAS club used to do some "re-enacting" at local events, and usually part of the act involved demonstrating that balnks really aren't that safe. Using a blank loaded with cream of wheat, throw up a coke can and shoot it. The damage done by dry cerial on a can is pretty impressive. And cream of wheat in a shoptgun blank can stick together in a lump and cause a pretty good bruise even at a good distance. So we quit using it, last I heard, the standard for the shotshells was a thin layer of florists foam over the powder- and the shells were cut in half, just barely long enough for the powder and foam, to prevent any posssible mixup with real shells. My usual was a C&B with just enough cornmeal over the powder to prevent it from chainfiring all the chambers at the first shot. And then, always aim at the ground , not at the other guy.