I recommend putting at minimum a stock wax- but I prefer to put in an oil finish- on all the mortises, end grain, under the buttplate, for instance, and in the barrel channel and tang mortise, to seal the wood well. Waxes don't prevent moisture from entering the wood. Linseed oil, even boiled linseed oil won't either. However, a good stock finish, like those mentioned, have driers in them and they do seal the wood. You can also put a good all temperature grease, like water pump grease, in the stock channel to help protect both the wood and metal on the underside of the barrel during rains. There are some newish lubricants that are made from silicon gels that stay soft to unconscionably cold tempertures, yet do not melt in hot climates, either, which you should also consider, particularly if this is a gun from which you are unlikely to remove the barrel from the stock frequently for cleaning.I also put stock finish, thinly, in the lock mortise, to seal those open grains, and protect the water from oil, water, and anything else that might get into the lock. That level of protect has paid off for me when I have hunted all day in the rain, or spent a weekend camping out, with the weather changing daily, and always some rain during one of the nights. Use a common household furniture wax, unless you just have to spend a lot of money on wax, to help protect the finish and wood, and metal. I have found that wiping down the barrel and ferrels with a cleaning patch containing NL1000 protects the metal from rusting very well, but if the gun is handled much, the surfaces need to be re-greased before leaving the gun in a case, or in camp for any length of time.