From The World of Truth otherwise known as Reddit posters, several of whom claim to be professionals in the film biz:
*gun may have been pointed at the cAmera not at people but Assistant Director and etc were sitting behind camera
* prop guns are real life guns, often old ones, because fake ones are too expensive to make
* there is on set safety protocol for handling prop guns and yes, someone screwed up big time
* blanks must be used because real life sounding fire is
important! ….this countered by many more posts that say NO! Explosive sounds are added by foley artists in editing…so who knows the truth
*realistic scenes require smoke of a real gunshot, CGI is way too expensive to get a realistic simulation….this countered by CGI pros who say “not at all…smoke is easy to produce…”. So who knows