I recently purchased a DGW .41 Cal derringer. I wish to use Hodgon Triple Seven instead of real black powder. DGW recommends 10 grains of black powder. How much should I reduce this 10 gains when using triple seven? I understand that Hodgon Triple Seven is FFF3 in density. I plan to use patched .395 balls. Any advice would be appreciated. Thanks.
Ed
Ed