Several good suggestions so far. As a dedicated flint shooter, I'm feeling compelled to add my own thoughts.
Success with a flintlock requires learning a whole new set of skills that I refer to as "Rock maintenance".
Find a source of good quality flints of the correct size and you're halfway there. Of course..to do that you first have to learn what constitutes a "good quality flint" and what size your lock prefers, which means you'll likely have to try a number of different types and sizes to identify what your lock likes best.
You do this by shooting..A LOT.
I went through a number of suppliers, types of material, and sizes before settling on what I use now(exclusively). All good experience, all learning opportunities. :thumbsup:
When installing a new flint, pay attention to how the rock orients in the jaws of the cock and make sure that when it impacts the frizzen that you're getting FULL contact of the edge of the flint with the steel face of the frizzen. To do this, I'll use a "soft install" where I get the rock/leather in the jaws then tighten it down to the point where the flint can still move jusssttt a little, not to the point where it's locked in place. Now, holding the cock, trip the trigger and lower the rock into contact with the frizzen face..allowing the rock to orient itself into the best, full contact position, then pull the cock back to half-cock, and tighten it on down.
I don't use the foot of my frizzen to pressure the edge of my flint as some have suggested. That's just me. Over time, I have acquired/made several tools to use to knap my flint while still in the lock. The choice of which one I use depends upon the condition of the rock, what needs to be done, and where I am.
FWIW,IMHO, anytime I get something close to 50 GOOD shots from a flint, I'm pleased. Some give less, some more. (I keep track btw). 60-70 is pretty common. I have had one go to 100, but that's unusual.
That doesn't mean more shots couldn't be made, but the quality of the ignition degrades to a level I'm not willing to accept for offhand shooting. Your choice of what is acceptable will probably be different from mine.
Oh, and btw...the first shot, or two with a new flint have been PROVEN to not be the best in terms of ignition speed. (Thanks Pletch)That's why I always dry fire a shot or two with a brand new rock before loading up and going to the offhand line, or into the deer woods.