As with almost every question asked on this forum, you got a variety of answers. Bottom line is, in this game, you must experiment, try several ball sizes of pure lead. The most popular patch material is ticking that is about .015" thick and available from several retail sources, like Walmart. Personally, I think trying is a better approach than buying and using expensive measuring gauges. And, trying is an excuse to shoot more. What better way to get acquainted with yer rifle gun?