FF vs FFF

[paulvallandigham]

First, you need to screen the powder, whatever you buy, so you get uniform burning to determine how close it is to another powder, either one made by the same company, or another company. Second, always read the literature. Because Goex has been the standard in America for so many years, most other manufacturers will try to give you a comparison with Goex. Or check their websites.

Third, nothing beats running loads over your own chronograph. Since you can buy an adequate chronograph for under $100, there is no excuse not to have access to one, even if you have to get a bunch of friends to share the cost, and the machine for their shooting, too. You will find that sifted powder will generally give you more uniform velocities, load for load, than unsifted powders. For flintlock shooters, the nice thing about sifting is you can generate enough 4Fg powder for priming from cans of 3F and 2F that you probably don't need to buy a separate can of 4Fg priming powder. BTW, Goex Cartridge Grade BP is sifted 3Fg powder, so you might want to buy a can of that to use in your muzzleloader if you don't want to invest in a sifter.

 

[Zonie]

... I've heard that if you switch from Goex to Swiss, a 15 to 20% reduction in volume should be made. Why would that be if the two 3F powders were the same? What if you switch from 3F Goex to 2F Swiss? Would you still reduce the load?

As I understand it, the granulation size of Goex and Swiss 3F is about the same.
The amount of power in a given amount of Goex and Swiss is not the same. The Swiss powder is more powerful which is the reason folks suggest using a reduced load. I believe it has to do with the amount of salt peter and the type of charcoal that's used when they make it.
I have heard that Goex is sometimes called a "Common" powder and Swiss is a "Sporting" powder.

As for comparing 2F and 3F, that's a "whole nother" story.