gun flints are made just that way woodrock . IE they are not Knapped , they are snapped .
In so many words , first a long shard is struck from the flint stone ,using a specific type and weight of hammer. This produces a flake that’s much like what one would want when making an arrow head or knife blade from obsidian ..
That first flake , from what I have read , is then knocked off at even spacing’s that’s dictated by how long the finished flint should be .
Then they come back with a different hammer and strike between the first strikes . This produces a flake that’s beveled on both edges and flat on the bottom . IE you get a double edged shard that will make a double edged flint or one with a steep back , depending on the angle of the 2nd striking
then it gets to a block and snapped to width . If need be the sides ate Knapped alittle . But not the striking edge .
Now that’s in so many words making an actual gun flint like an English gun flint as described by Sydney B. J Skertchly ;The Manufacture of Gunflints
Here is the online read of that book
http://archive.org/stream/onmanufactureofg00skerrich#page/n5/mode/2up The other way is to make a nodule type of flint , which is struck directly from the core like we would do to make a arrow head .
Now when we put it in our locks and that striking edge gets worn , that’s where the Knapping comes in so as to work the edge to keep it sharp .
There are probably other ways that are done today . But speaking for myself , I find that a properly made flint . that’s of good grade and thickness , will not only out last as cut flint , but they are also fare easier to maintain