I often carry single actions on the farm, and particularly, if I'm in a hurry to get to town to pick up a part before business hours close, I don't bother changing out. A coat works fine in winter, a long shirttail in summer.
The older single actions hold five with one under the hammer empty for safety. My memory may not be what it ought to be, but offhand, I'm not recalling a time when I had to shoot more than five bad guys. There's a good chance that after you popped the first couple, even if the rest of them didn't run away they'd be in such confusion that you might have time to duck behind cover and drop a few more in the cylinder.
Arguments might be made for more modern guns--I've read a few--but if you reach under your coat, and it's a single action, there's no sense in thinking about it then. Fight with what you have.
If I really expected trouble, I'd think long and hard about going to town with anything.
A good thing to do is to step out on any early summer morning and look at the dead bugs under an all night security light. They didn't have enough sense to stay away from the bright lights, and it killed them. People aren't as much smarter as you'd like to hope.
Somebody with a twenty round capacity double stack might read this and smirk "But I can afford to miss." I might miss. You might miss, but nobody can afford to miss because a better shot might be hitting while we're wasting time missing.