ORIGINAL: frontier gander
Sounds like your frizzen needs to be rehardened. They shouldnt be breaking easily like that. Take a lead ball, pound it flat and wrap a flint in it and trim off all the left overs. I tried using leather but kept busting flints, Switched to the lead and started getting great spark and around 50 shots with 1 flint.
HuntaWay:
See this link for the lead ball to flatten:
http://www.chuckhawks.com/flintlocks.htm
a lot of other good tips in this article also.
Chap Gleason