When the slug (or conical) is then pressed into the case past the driving ring, it compresses and fixes the powder/filler column.
It looks like oldknotty is talking about revolver cartridges here, which is what I'm assuming. I don't know anything about sharps cartridges, but I don't think revolver cartridges are stout enough to press a bullet into and compress powder and filler to the point that they won't mix.
so... I'm corn fused...
the paper cartridges we're talking about you're just tearing open, & dumping the powder??? or are you biting the end off, & actually putting the paper in ( or does the paper rupture enough that it fires fine in paper...
if the ball / bullet has to be rammed home anyway, why use any filler ??? or is the "chamber" not rifled & you get poor accuracy if the ball is in too far???
sorry... just starting to get into black powder brass cased loading, so I'm trying to understand paper...
FIL had plastic / glass tubes, that he pre-measured powder charges into, but didn't use paper
According to Round Ball to Rimfire, originally revolver cartridges were much like musket cartridges: Little paper cylinders that contained the powder and the ball, and you tore off the tail to access the powder which was dumped into a chamber, then you removed the ball and pressed it in also.
This was noted as being tricky because it was hard to get the powder to go into the cylinder you were aiming for.
Soon they developed "combustible paper cartridges" for the revolvers. These were paper, foil, or gut tubes wrapped and formed on a conical mandrel, which were filled with powder and then a bullet glued in place to cap them off. These were inserted whole into the chamber and then rammed down into place. Upon firing the body of the cartridge was, in theory, consumed.
This video gives a nice overview of a modern reproduction method:
http://www.youtube.com/watch?v=-2HUcfAyaaQ
You will notice that in the video Balázs also says you can put filler in the cartridge. I suppose
if you can push the bullet firmly enough, and
if[ you don't shake your cartridges too much, then you may get away with it.
My own experience with loose filler was when I poured in the powder and then some filler but not enough filler so that the ball bottomed out on the filler. Consequently there was loose powder and filler in my chamber under the ball, and they mixed during firing.
It's possible my concerns are unfounded, but personally if I was going to make under-strength paper cartridges I would use wadding as a filler as there is no way for it to mix with the charge.
Here is a picture of a period cartridge:
Steve