What is gun handling? Exactly what it sounds like—handling a gun. If you're in a life-or-death situation and you have to think about how to use your weapon, you're probably already dead. There's not a lot of functions on a pistol, but they should be automatic. Each finger/thumb knows where it's going and what it's doing without much input from my brain. Kinda like if I'm on the couch and I want something from the fridge, I don't have to tell my legs to get up and go that direction. They just do it. My body knows how to complete the task without any help from my brain. If my goal is to shoot a target, reload, or chamber a round, my hand operates the same way.
Getting comfortable with a weapon doesn't have to be a chore, as you can see in this video. Dry firing for speed, well, that's a different story. This is more just getting comfortable with how the gun functions. Of course, I always check and recheck my gun before any dry firing session and never point it at a human regardless of how many times it's been checked.