Before you hunt... take some isopropyl alcohol and swab the bore of the rifle. Then a couple of dry patches follow. Next, take that same patch that has the alcohol on it, wipe the nose of the flint off, the frizzen and the pan out. Let it sit a little and it will dry itself. Now after you load the rifle, put your powder in the pan. The idea is you want no oil what so ever on the flint or the frizzen.

When I nap a flint I do the same as NCHawkeye except I use a 6 penny nail. First I grind the nail flat. My wheel grinder does that. Then I like to cut a L into the end of it. What I mean is grind off about half that nose so there is a small lip on that nail.

If you are napping, be sure the rifle is not loaded, and the pan is empty. Or put a cloth in the EMPTY pan to make sure should a spark be produced, it does not fall in or near the touch hole.

Then set the rifle in half c0ck. Then at about 90º put the lip of that nail on the edge of the flint and then tap it lightly with my brass hammer. Sometimes it does not look like anything comes off, but you'd be surprised if you rub your finger over that. Work the entire edge. Now you have a napped flint.

Some people shoot ten or more times and then flip the flint so it naps itself. I tried that but it does not always work. When you set your flint in the jaws of the lock.. at half c0ck there should be about 1/16th of a gap maybe a little more, before that flint hits the frizzen.

Normally on a Thomas Fuller black English flint I get around 40-50 shots. I use leather to hold my flint in the jaws. Some people use a flattened lead ball.