I use to use RWS caps and pistol caps from Navy Arms. When I was no longer able to find them locally I bought CCI. Had great luck with both. Never tried CCI musket caps, just the RWS and Navy Arms marked caps. My hoarded musket cap supply from the late 1960s is mostly gone but I have managed to augment my supply a little thanks to a kind person on a forum who sent me his remnant supply that he no longer needed. Still, have to find a supply of winged (RWS) musket caps as I have great confidence in them.