I'm off an on making flints. Lost half my regular job and took on another part time job so am working 6 days a week at reduced pay. Doesn't leave much time for collecting rock and making flints. Hopefully things will turn around work-wise.
I don't care that much what material the flints are made of. It is possible to get dull flints of any material. Or poorly shaped flints, or flints with internal flaws. Flints that are too thick, too thin, too humpy, or too smooth topped will function poorly in a given lock. More on that below. Asking if French or American or English flints are better is like asking which of them makes better beer. I guess it depends on the maker of the beer as much as where it is made.
Whether English, French, or American chert, more than half of a flint's useful life is determined by the USER. A loosely mounted flint won't last long, nor one that isn't mounted well in the first place, so that it will scrape the frizzen. And a user who knows how to carefully knap an edge to just remove the offending leading edge that is now rounded, will get a lot more shots than someone who renews the whole edge every time the flint gets dull. Because that heartily-knapped flint will get short in a hurry.
Different locks do well with different thicknesses and acuteness of edge of the flint, so the choice of SHAPE is important in determining how long a flint lasts. I want a tough, less acute edge on a basher lock like the Harpers Ferry 1803. I would want a nice thin edge on a finely tuned lock that does not seem to rebound much.
For the beginner flintlock user, there are many mysteries. But the frontier fella who showed up at the trading post or even the townsman who went to the gunsmith shop had to make do with what was available. I don't read in period accounts, "Samuel needed flatter topped flints no less than 5/8" or more than 11/16" wide and between 3/4 and 13/16" long. He could not get any in that size so could not join the hunt. When the enemy came upon his home he set up his blunderbuss as a matchlock and tried to fire his useless, wrong sized flints as projectiles to good effect, but they apparently went everywhere but on target and he got kilt." Ok that was an exaggeration, but my point is you should have a flintlock that is not finicky about flints, and you should be willing to change flints every 20 shots. That seems to have been the norm for soldiers. 20 shots is a lot of shots unless target shooting. Most skirmishes probably did not result in 20 shots per man or cartridge boxes would have held more. We get caught up in thinking we need to get 50-100 shots per flint or our lock or the flints are no good. That was probably possible only late in the flintlock period with finely tuned and expensive locks, and the gentleman who could afford such fixins could afford a few extra gunflints.
Those are my contrary thoughts on gun flints!
