Having been more into bird hunting with flint guns I never used a leather cover on the frizzen, no time to get the gun to full cock AND take the frizzen cover off before the bird is out of range. I hunt with flint fowling guns the same as modern doubles, with the front end pointed in a safe direction. A cover might work if you're working over a god dog, but you're still going to have birds flush when you least expect it.