Expanding on Cayugad's point about the flint, what are you using to secure the flint? You should be using lead it holds the flint *a lot* more rigidly than the leather. This translates in to more sparks per frizzen strike and less hang fires.

Put a lead ball on concrete (driveway, sidewalk) and tap it with a mallet or hammer to flatten, trim to the correct shape with snippers. Wrap the lead around the flint just like you would with leather. Tighten the jaws. Wait a little while. Lead being a soft metal it will need some time to conform to the shape of the flint and fill in to the groves of the c0ck jaws. Re-tighten. Once the lead has taken to the correct shape that flint will not budge. It also makes knapping much easier.

Good luck!