Ok, I think I know what you are trying to do, but I also think that you are over-engineering it a bit. But, I think that you have some interesting ideas to toy around with. The gellatin fill is a good idea, at first. If you have a thicker fill, then it will resist spinning inside the shell, but will tend to spin with the shell. But, you do want to be able to mark your target when it hits. Too thick and it wont be easy to tell if you have been marked. That may be a problem to deal with later. As for the inside supports, that seems to be a bit of a manufacturing nightmare. But, how about this: No supports, but make the inside of the shell (one side of the gellatin sheet) a rough texture to grab the thicker fill and spin the fill with the shell. Not perfect, but not hard to do either. When the gell sheet is made, just have one side of the rollers dimple it with the geometric shape of your choice before it goes to the ball press. Then when the ball is formed, the thicker fill will tend to rotate in the direction of the shell. You dont have to design a new gun, or loader. It will work in any gun or barrel on the market, but may perform better in the rifled barrels. Just my thoughts on this.
WOW, sigs. Havent seen these in a while here on AO.