RE: knockdown power... fact or myth?
From snopes:
Jon-Erik Hexum (died 12 October 1984)
Hexum died of a gunshot wound after he accidentally shot himself in the head with a .44-caliber magnum pistol loaded with blanks while on the set of the TV series Cover-Up. Wadding from the blank cartridge had been driven into his skull. Hexum was replaced in the series by Antony Hamilton, but the show didn't last all that long, running only from 22 September 1984 to 6 July 1985 before being canceled.