add bulk to black powder charge
is there something I can mix with black powder to increase bulk while retaining the power? I have a smooth bore cannon very much in scale to a pre Civil War Mountain Howitzer, 2.7" bore. My preferred load is equivilant to 1 1/2 oz. powder to nicely lob a concrete ball. Problem is, the flash hole is positioned 3/4" forward of the rear of the chamber and that small charge doesn't extend forward enough for the fuse to reach it. I need a charge equivilant to 2 1/2 oz. to do that. What I'm asking is can I add (mix with) something to that 1 1/2 oz. to roughly double the bulk. Sawdust? Oatmeal? Catlitter? anything?