The actor that played gimli is over 6 foot tall. There's never been a 200 foot tall lizard attacking Tokyo. You can shoot a movie with guns safely without violating the most basic safety rules.
If you hire roofers, tell them to fuck off when they give you a safety orientation, and you've already seen them drop two hammers off the roof, can you really say it's not your fault when you get clobbered?
The only exception to point a gun at somebody is to protect life. If you can't film a shot without pointing a real gun at someone, that shot doesn't need to be made.