My practice is to take it down after hunting season, run a patch with some solvent through(amazing the amount of crud that builds up in there), wait for it to dry, then wax inside and out. Spring and follower get waxed as well. I wax the whole gun, I hunt in what's basically a swamp, rain/snow usually happens during the season. You don't want oil in the tube, it'll be a dirt magnet. I also have put stock finish on the stock inletting and the inside of the forearm, Marlin never finished those, then wax those areas as well. That's for a hunting gun, if it's just going to the range, you don't need that.
Stan S.