Re: How long does a flint last
If the lock geometry is right and you have a good flint, they can last 200 or more shots. Some flints in some locks don't last 10 shots. A chip isn't necessarily a bad thing, it just isn't good. You didn't say what kind of flint you are using or what lock. Some frizzens seem to eat flints rapidly.
I like to pick my English flints out of a bowl full. They should be a uniform translucent gray, with no brown spots or muddy swirls. Hold them up to the light to look for fractures or chips. Don't buy them if they have muddy spots, chips or fractures. You want a straight edge about as wide as the frizzen. It should be short enough when in the jaws of the hammer that it doesn't contact the frizzen at half cock, but long enough to point to the middle of the pan when lowered all the way toward the pan, (with the frizzen out of the way) Sometimes too much resistance on the frizzen spring can cause a flint to chip prematurely. Try making sure the frizzen arm to frizzen spring contact is smooth and lightly lubed.