F guff, how did that rambling diatribe have anything to do with the OP's question? Auto mechanics? I thought this was a reloading forum?!
Fillers have been used with great success in cartridges for eons. In the case of a square of dacron pushed down on top of the powder, it holds the powder there by friction of the square of fabric on the sides of the case. It's very light weight does not affect chamber pressure. OR ring a chamber. A solid wad would do that, IF it happened to come loose from the bullet to position itself between the powder and bullet.