Yesterday I replaced the flint and checked the alignment with the frizzen. Noted the flint would strike the barrel flat, loosened the jaw and relocated the flint away from the barrel enough to clear.
There was a slight amount of flint outward of the frizzen but then knapped flints are not known for precise and consistent measurements.
Lock geometry can be slightly altered by how the flint is mounted - bevel up or down, flint further out or into the jaws. Experimentation is part of the alure for me and others. That said some lock geometry is indeed too far out to produce desired results.
Most locks with a well hardened frizzen (preferably thru hardened and not case hardened) and a strong main spring will function. Some require refinements on the pan to catch all or even one spark, size of the touch hole, location of priming powder all come into play and some rifles are just more finicky than others.
Start with using real BP in both the main charge and pan, properly fit a sharp flint, wear eye protection.
If you are still having problems, hook up with an experienced flint shooter or wear eye protectio. If still on your own, do not load or prime the rifle, set it up where you can be eye level with the lock and cycle the lock in the dark or very dim surroundings to see what is happening. Such as few or no sparks, sparks hitting in front of the pan etc. If that seems to be working OK, then prime only and see what is happening.
Good luck and keep us informed.