the lock is the heart of a flint lock.. the flint is quite important part of that lock.. i have locks that are very powerfull, too power full for the flint they were designed for.. for these i order square flints from the track of thewolf so i can use wider flints in a lock desinged for a narrower flint. this keeps the lock from eating the flints up too fast... if the lock is weak you use a narrower flint so it can have enought power to shave off steel... .. i have an ol tower japan made bootpistol. it has poor steel in the frizzen and the sawn flints work best in it for some darn reason.. so try them all, see what works the best. then put the bevel up and bevel down.. flash hole size is also very important to fast ignition. make sure you have the best load for the gun before you start making it larger.. .070 flashhole has been found by some experts doing very stringent tests to be probably the best all around vent hole size.. keep the frizzen and flint clean by wipping it during long fireing sessions for best preformance.. if your getting chips of flint spitting into your face upon ignition, overlay the flint with oversized, that is wider, leather in the jaws to stop this... dave..