I am not going to pull my rifle out of the stock during hunting season, that requires another trip to the range to verify zero. You can minimize a different point of impact by marking your screws with a graphite pencil.
In bad weather, I hunt with a finger rubber over the muzzle, if you don't have a finger rubber, put a piece of masking tape on the muzzle, and keep a piece of masking tape on the "off side" of the butt stock just for this purpose...just in case.
I keep a cloth in a plastic bag to wipe down my guns with. Here in the South, about the first half inch of the barrel gets a lot of rust in it due to bad weather and heavy humidity.
When you get home, you can run patches down your barrel to remove moisture. I use "punch" type jags that fit so tight that I have to put the patch on the jag way off center.
If you put oil down your barrel, your impact will be lowered in the area of 1/2"-1" at 100 yds from the velocity loss.
Please do not put WD-40 down your barrel, this stuff runs down the barrel into your trigger group, and will turn to varnish over time.
Be careful of what kind of coating you put on your gun, when the coating gets scuffed up, the rifle really looks horrible. It is just about as easy to go to wall mart and get Krylon and spray paint your gun, then you can just touch it up when it gets scratched. We go up and down trees, hunt out of deer stands hauling out guns through tree limbs, guns take a beating. Stainless guns with camo tape on them work well, just make sure that it is the NON reflective tape. For coatings, I like Black Chrome, Satin Nickel chrome, and Black Oxide available from Robar, these coatings will NOT scratch or rub off under any circumstances.
Many guys have half a dozen deer rifles, having them all coated is a major investment, and the vast majority of guys struggle to get just one decent rifle/scope. Degreasing the barrel and action, then applying good thick "duct" quality camo tape goes a long way in protecting finishes for those on a tight budget. I just pulled the camo duct tape off a Rem 1100 that had been on since the late 80's, there was zero rust on the barrel or action.
So, a finger rubber or masking tape to cover the muzzle eliminates rust in the barrel, wipe the gun down good with a quality oil, Push patches through the barrel with a tight punch type jag, and you are good to go. If you have got caught in a rain storm and the rifle got soaking wet, or you like to hunt in the rain like I do, then to the extreme you feel necessary to protect the gun. I have an All Weather Ruger stainless just for this hunting application, it gets very little attention other than a finger rubber and a wipe down.
One thing to remember, bringing a cold wet gun in a warm house is a recipe for disaster as rust will set up within hours. When I was 17, we hunted dove in the pouring down rain. Brought the shotgun in the house, sat it in the corner, two days later it was a rustbucket.