Yea well I knew that, but I thought Gunnery adjust how much dmg your guns do. In your last post you said I should worry about my HP if it takes me a long time to kill NPCs. For me, most NPCs take between 3-4 shots of my guns to take down, each gun doing about 500-600 dmg each shot.
What Aguila Saber was getting at, I believe, is if your enemy has chance to fight back (i.e. you can't guarantee sinking them in one or two barrages), you'll need more HP in order to withstand them returning fire.
I, personally, take several barrages to sink anything, but I have oodles of HP and cheap repairs, so it doesn't really matter. Except when someone way above me attack me and sinks me without effort, which happens every day, more or less.