Why would people be shooting a gun for fun on a movie set and who would think using a gun that will be used in the movie would be a good idea? What I think its this movie seems to be set in the old west so the gun is kind of a old relic and someone thought it would be neat to shoot using a gun from back in those days.
They are not old relics, they are still made today and their metallurgy and internal mechanisms are very modern. AFAIK all modern single-action revolvers that are made to look like just like those from the old days now have manual safeties to prevent accidental discharge (the reason that the old time guys only loaded five instead of six, with an empty chamber under the hammer). But yes, a box or even one round of "real" ammunition anywhere near the set should have sent up all kinds of red flags for anyone who saw it. It's giving me the heebie-jeebies right now to think about it.
Being former military, it is drilled into ones head, for Weeks, Don't point the gun at anything you don't intend to shoot, and keep your booger finger off the trigger till then. Even blanks can be harmful, look at Brandon Lee, a blank killed him because no one checked the barrel to see if there was anything in there after the previous use.
Yes indeed. If you want to be screamed at for a while about every way you are a disgrace your species, do something unsafe on a military gun range. There is a scene in the HBO WW2 series
The Pacific (based on a scene from a wartime memoir) when an marine officer is taking target practice and is not paying attention and lets his pistol muzzle move back toward the firing line. A sergeant screams at him and IIRC throws a handful of rocks at him; the fact that it was a superior officer never entered into it. That attitude is real and has been around for a long time.
When I was a kid and took the Hunter Safety course (with a lot of my classmates) the first thing that they told us was TREAT EVERY GUN AS IF IT IS LOADED AND READY TO FIRE. When someone hands you a gun, you open it up and check if it's loaded, and you keep it in a safe condition until you are pointing it at what you want to shoot. Whatever you shoot at can be destroyed. And when we went to shoot our .22's, the instructor chewed a 12 year old kid out for horsing around. I still remember it. The kid was about to cry, but he got the message: These are killing machines. If you don't want to take it seriously, stay home.
Another thing I just remembered: A friend of my dad's who was an avid gun collector and shooter and fixated on gun rights (he was considered pretty extreme for the time) did not allow his kids to have toy guns, because he did not want them to develop bad habits of pointing guns around.
In the old days, there were institutions that reinforced that safety culture. The NRA was largely a safety and training organization. There were riflery clubs at high schools all over, even places like Brooklyn and Queens. Boy scout camps had shooting ranges. There were a lot of veterans around to help impart that safety culture. Do many institutions like that still exist today? I'm out of touch, I don't know. But firearms are scary, and when they are unsecured and being handled, having the figurative hair stand up on the back of your neck is not a bad thing.