I generally buy all my flints from Track of the Wolf. They advertise sawn flints if that’s what you are looking for. I generally shoot the english hand knapped flints. Good luck.
If not there try the Log Cabin Shop in Lodi Ohio. They been in business for a long time and are good folks to deal with. Google will get you contact info.
Founder
Ancient Order of the 1895 Winchester
"Come, shall we go and kill us venison?
And yet it irks me the poor dappled fools,
Being native burghers of this desert city,
Should in their own confines with forked heads
Have their round haunches gored."
WS
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