I use the flip-up caps as well. I never worry about the synthetic stocks and I have them on all but one of my rifles. The only worry with wood that I have found is to be sure that the barrel channel in the stock is sealed with something. Many are just raw wood on the inside if the syock. If so rum a good water seal into the wood or use a good wax. I just dry everything off as soon as I get home and if need be, apply a little oil to the metal surefaces. I stick masking tape on my muzzle loader muzzle to keep out water or snow.