Quick note on guns that shoot a lot before reloads. You are right that sometimes it is ridiculous, but sometimes the filmmaker is trying to show what is happening in two separate locations or from two separate angles at once.
Take a cowboy on main street who pulls a gun and fires 3 rounds at the good guy, then the scene cuts to inside the saloon where you hear 3 gunshots and people dive for cover. I've been watching movies like that where someone will claim 'his gun is empty now! he shot 6 times!' and then roll their eyes when the camera goes back to the cowboy on the street who shoots at least a few more shots.
Now, I also think realistic ammo consumption and the need to reload could add a lot of tension in scenes if it was done more often. I think of the movie No Country for Old Men. The main character (Llewellyn) buys a shotgun and some shells then cuts the barrel down in his hotel room. I'd have had him buy a shotgun and have some chatter with the guy about shells. Something along the lines of
"I'll pick up some buckshot too"
"how many boxes you want?"
"five in a box right?"
"yes sir"
"then I'll take two boxes"
When he cuts the gun down he loads up 5 shells and puts the other box in his pocket.
Now, when the gunfight scene happens, one where there is not a ton of shooting, the audience (or at least the smart members) know he's got a handful of shots, and you can set up a scene where the gun goes click at a bad moment. Heck you can even have him drop the box and the shells roll now he has to grab for em etc etc.
You wouldn't want EVERY gunfight to have the hero end up reloading to increase dramatic tension, but I'd like to see it a lot more. Plus just reloading in general.
I'd also love to see a shootout where the whoever shoots 6 times with a revolver then some smug bad-guy steps out and notes the shooter shot 6 and is empty. Empty gunner then pulls a snub out of his pocket and shoots the guy dead. Or even better shoot one more time then as the guy is dying remark 'most revolvers nowadays have 7 shots'