I drove out to my favorite Ma and Pa's Grocery/Gun shop this morning. I found these little do dads laying is a box of misc. what nots. So I grabbed them. I'm sure they are for a side lock rifle, but they seem to work pretty good on the Revolver nipples as well. I will try them out and see what they do when fired. It says they contain the cap when fired (no cap jams in theory), prevents loss of cap, and keeps moisture out of the cap. We shall see. But I figure they might be useful for keeping the revolver loaded or carrying it for extended period. And if the are not worth a crap, then I can use em for Striper Jigs. Still a buck eighty nine well spent.