... suck big time. Or, how to waste time with something that will never work instead of doing the right thing from the get-go.
An old "common" (double edged) gun flint with many dozens of good firings finally lost its edge, After 3 failures I flipped it over to its second edge, which was also a tad worn. After 2 failures I had enuf and swapped it out for a new flint that wouldn't spark on its first flight and required a bit of knapping. When I brushed the ultra tiny knapped flint shards off the bench I got a nice 1/4" cut on the pinky. Flint can be surgically sharp, beware!
After that, she fired consistently, as expected. Life is still good, despite the waste of time.