In bad weather, I've been covering the muzzle of my rifles, modern or smokepoles, with tape for years, never hurts accuracy or anything else for that matter, just blows a hole thru the tape. Started doing that about 35yrs ago after shooting at a spike elk with apparently some snow in the muzzle of my 30-06 rem 760, blew the front sight off and create a bulge where the front sight was.....didn't get the spike bull, either! The rifle became a carbine after that!! Duct tape or black electrical tape works, so does a balloon or a finger cot.
Tim