3F is to quick and too rapid at producing max pressure for any but the small bores or short rifle cases up to .45 cal.

Most ctg. shooter use 2F as the finest granulation and many use 1F as it can produce the best accuracy.

For expample, using 500 to 530gr. cast grooved/lubricated bullets, my .45/60 chambered Sharps delivers sub 1 3/8" groups with 60gr. 2F, under 1" groups with 60gr. 1F. With 60gr. 3F, it produces best groups of around 2"-sometimes, but is a bit erratic with unexplained fliers. The velocity increase given by 3F is slight and with bullets this heavy, 50fps is nonexistant.