I frequently have enquiries regarding correct flint selection for a range of guns, so thought it would be helpful to provide some advice.
After speaking to several experienced ‘veteran’ flintlock owners, all gave exactly the same advice. The correct gunflint size for any lock can be determined by measuring the width of the frizzen. Using a flint that will strike the maximum width of the frizzen will, of course, produce more sparks per strike. The only width restrictions are that your flint must not be wider than the frizzen. Also, care should be taken to ensure the flint does not strike the breech area of the barrel, to avoid the flint shattering on impact and damage to your barrel.
A good test practice is to use a wooden flint, or piece of stiff cardboard to see if a given flint width makes contact with the barrel, by releasing the lock by hand to allow it to follow its full striking movement. If it does make contact with the barrel, safer to select the next width down.
Once width has been determined, all you will need to measure is the length of flint you need. This is also where a wooden flint can be useful, as it can also be used to check which length might either struggle to correctly reach the frizzen, or make premature contact if too long. Some locks are happy with square flints, others require a slightly longer flint. I offer the choice of both, all you need to do is follow the above suggestions, and you will know exactly the size for your gun.
If you require gunflints of any size not listed in the shop options, please just drop me a message, I’m happy to make exactly what you need.
I also have had some confusion with width v length when ordering. The format I follow is that the width of the flint as listed for ordering is the width of the firing edge (the edge that actually sparks against the frizzen). The length of the flint is the measurement of the side, from firing edge to the heel (back) of the flint. Please see the illustration below (you can click on it to view full size).