"bout three decades back I built a matchlock. Used Italian styling, as Italian weapons were popular with early 17th century Englishmen. Built it with a long sear bar as I though triggers rather effeminate. Used a rifled barrel because I had one. Took it to our Michigan Canoe Shoot. All these guys in buckskins with tomahawks in their belts asking "will that thing go off? etc. Just like being 20 again, confusing other hunters by running a stick down the barrel of my double.
Anyway I never shot better. Hit the gourds floating down the river. Moving, albeit slowly, targets mind you. And on the firing line, at steel targets, down the line I heard a lot of click click #@!!&^%. Not me. Always went BOOM. Gentlemen, may I suggest that when a lighted match-cord is in the vicinity of black powder one is pretty much guaranteed some kind of explosion, somewhere. Fortunately I survived. Not wishing to tempt the Lord my God I sold that rifle to a re-enactor. It was fun, though.
Made my match cord with hard-to-find cotton cloths line soaked in saltpeter.
That is the wrong way to do it.
May I refer you to
http://www.musketeer.ch/blackpowder/lunte.html ? This tells the proper way to make slow match. Involves boiling cord in some manner of lye, which dissolves out the lignin leaving just cellulose. It is exactly how Kraft paper is made. Anyway read what Mr Bretscher has to say. And good luck!