There are several components to a successful flintlock.
Firstly, not everyone is a smith or is handy enough to play around with these things, I'm certainly not. A good gunsmith can tinker with your lock and have it set up well no worries.
The other component is your rifle itself and that part is on you. flintlocks are very finnicky and each has personality. By that I mean they all have an individual preference for the flint used, flint position, prime amount, prime location, leather wrap used etc. You will just need to practice and try a few things to find what it likes, in this you may have some delays/failures in fire that are not geometry related.
As a couple of examples, my first flinter was a Pedersoli trade gun. When I first took it out I got about 30% fire rate, but when it fired it was almost instantaneous so I knew it couldn’t be the lock. I ended up playing around with it and finding that it liked a fair bit of prime. In the end it was pretty much 100% unless the flint was dull.
Another gun I simply could not get it to fire more than 10% of attempted shots. Again when it did, it had very fast ignition. I’d almost given up when I realised it did much better with a smaller flint, it should have taken a 7/8” but sparks consistently landed forward of the pan. Bringing that back to a 5/8” completely solved the problem. Now that one may have been a geometry issue but I was able to completely fix it by simply trying a different way of doing things.
My GRRW .54 is a pearler of a gun, but if it doesn’t have 4F in the pan I notice the delay. It’s such a reliable lock and is so gentle on flints (I’ve never had one last less than 50 shots) I wouldn’t dare tinker with it.
My Centermark 62 smooth Fusil de chasse doesn’t care what prime you use or where it is, she just fires and fires fast every time!
You may not get it straight up, but think of flintlocks as a journey that we all must go through. I promise once you have them and your guns figured out you’ll never look back.
