I finally found a site that shows a flintlock rifle being fired. Though not labelled,
there is a presumably steel plate above pan holding priming powder, at fortyfive
degrees to barrel of rifle, just ahead ot the hammer holding the flint, so that
sparks are deflected downward into powder in pan. Here's the URL:

http://www.uwyo.edu/ces/4H/Natural/Muzzleloading.htm

Again, I challenge the rest of you to discover etymology of "frizzen".

A book I am reading says "skinflint" for stingy person alluded to practise
of reshaping flint when it got worn, which might damage the knife used
to do so more than a new flint would cost - if you could buy a new one.