Even though this threadis about an inline rifle.. since hunting season is near or currently on us, for those with a traditional rifle that want to protect the #11 cap on the nipple and have an extra safety to boot...

Take a tire valve stem cap. A leather needle and some cat gut works real good if you want to poke a hole through it. Or you can hot glue some old shoe lace to it, and then with a good length, tie that other end off to the trigger guard. Put the valve stem cap over the #11 cap on the nipple and lower the hammer down on it. You have now weatherized that #11 cap, and there is no chance for a misfire. When you are ready to shoot, cock the sidelock and just lift the stem cap off and drop it... now shoot that big buck..