Film sets usually have strict rules about the use of prop guns. Specialists provide weapons for use on film sets and advise on their use.
"There's basic safety measures on every set," said Mike Tristano, an armourer who has worked with Alec Baldwin in the past.
"You never point a gun, even if it is not a firing gun, at anyone else. I'm at a loss how this could have happened and how it could have done that much damage."
A common shot in film shows an actor firing into the camera and Steven Hall, who has worked on films such as Fury and The Imitation Game, says it only happens with safeguards.
"If you are in the line of fire... You would have a face mask, you would have goggles, you would stand behind a Perspex screen, and you would minimise the number of people by the camera, " he said.
"What I don't understand in this instance is how two people have been injured, one tragically killed, in the same event."