Flints are ordered based upon the width of the Frizzen, and TC Frizzens are 3/4" wide.

A long time agothe 5/8" BEF was recommended and nobody has bother to change that...but in reality,the correct size 3/4" BEF's are outstanding in TC locks.

The little 5/8" size are too narow resulting in less sparts;
And they areshorter, resultingin shortened Flint life.

My experience with 3/4" BEFs in TC Flint locks has been outstanding, and I'm very particular with the components I use inmy Flintlocks...will only use the best/fastest Flints and without question these have proven the best to me.

Always align the inside edge of the flint with the inside edge of the Frizzen so it doesn't strike the barrel...if a little bit sticks out on the outside edge, as someone already mentioned, it won't bother anything.

Check to be sure you have TC's redesigned improved lock assembly, andthe3/4" Flints do best starting them in the bevel up position...as they wear & shorten, you can flip them over bevel down and get more life out of them.

October Country always had the best prices when buying bulk bags of 50 or 100.
Always specify Tom Fuller BEFs that are 3/4" x 7/8" long...TOW carries some from somebody else and if you're not careful, you might end up with3/4" x 3/4" which are shorter to begin with, and you'll have shorter Flint life as a result.