I normally use 'FF' in the barrel and FFFF in the pan, but I have a can of FFF sitting around that I would like to use up. I didn't know if using FFF in the barrel was an acceptable thing to do or if it was totally crazy and unsafe.

CB's little brother

Country Boy 3F CAN BE USED REDUCE THE CHARGE BY 15 PERCENT
I MYSELF USE 3F IN MY 50 CAL. FLINTER GOEX POWDER AND 4 F FOR THE PAN