That works if they’re going to add flash and sound in post-production. That might be more expensive than the flash that blanks would provide. Not sure how much CGI would be budgeted for a low-end western. I heard $5K for ammo, so...?
There are lots of possibilities. The scene could have call him just to point the gun at the camera and cock the hammer, or pull the trigger and cut right before the flash. Or, pull the trigger and add CGI.
Since this event I’ve been watching carefully shows where they have shootings, and watch how they frame and cut it. It’s interesting.
CGI for things like gun flashes is cheap and easy.