What grease to use to prevent flashover?

[airgunnut]

yep fine bp, a general rule of thumb is longer the barrel coarser the powder, in pistols fine bp, in carbines medium-coarse, full length barrels coarse, i was told the powder should burn nearly the full length of the barrel not just in the first few inch (the barrel gets warm along the full length, this was for center fire but i assume the same will be for bp)

[gtpkeeper]

many thanks