So let me ask this related question. How much compression does the powder need? The first time I loaded up my 61 Navy, I used 15 grains FFFG just like Pietta specified, no wad. The first two times I tried shooting it, the balls kept jamming in the forcing cone. I also noted one day that i could press the ball further down into the chamber with a pencil, suggesting that the powder wasn't compressed at all.
So I increased the amount of powder to 20 grains and added wonder wads over the powder. Now the gun (andits two brothers) shoot flawlessly. I also note that I am indeed getting compression on the powder.
So the question I guess is how hard do I press down on the loading lever--is there a "proper" amount of compression one wants to achieve? Or is this a variable depending on the powder? ON a tangent, I read around here somewhere that having gaps between the powder and the ball could be very dangerous, but I can't imagine why--wouldn't such a condition merely reduce the amount of pressure in the chamber when the gum was fired?