Another thing that works is the fingers of nitrile exam gloves from the DR.s office, or you could just buy them at the store. I use them on my muzzleloaders all the time, as long as there is a glove finger stuck on the barrel I know with out looking that there is a charge in the barrel, when I shoot it disappears. Where I live a muzzleloader is considered unloaded if the flashpan is empty or the percussion cap removed from the nipple. Just my 2 cents on keepin a barrel unobstructed...