James.
As I understand it, a ring in the chamber is caused by the combination of an over powder wad and an air space between the wad and the base of the bullet. In this case the wad in effect becomes the projectile and the bullet, even though it is still in the case, acts like an obstruction in the barrel. As long as you have the bullet seated against the wad, you should not have a problem. I use a "minimum" powder charge that will geve me about .1 inches of compression when the wad and bullet are seated.
As far as to the material for the wads, there are many things that will work and it seems that different shooters/rifles prefer different materials and thicknesses. I use a 7/16 hole punch to make mine. I currently use a .03-.04 cardboard overpowder wad (deviders between the bottles in a 24 pack of Budweiser), then a newsprint wad on top of that. Some folks like the poly wads cut from the lids of coffee cans, and then there are those that like a thin wad cut from wax paper. The cost of the punch was minimual, I think about $5.00 on clearance for the whole set. That's part of the challange of seeing what will work best- coffee can lids, cerial boxes, wax paper, tablet backing, etc., etc.
I would be careful about using lubed wads against the powder if they are to be loaded for a while. The lube can migrate into the powder and cause some of the powder to not ignite.
You can compress the powder with a dowel as you mentioned. I use a 3/8 x 1 inch bolt that I chucked in my drill press and turned the head down to just fit in my fired 45/70 cases. The other end is ground down to simulate the rounded end of a bullet. It is then used with the bullet seating die that has been backed off so it wont crimp the case. The depth can then be regulated as you would regulate the depth of a bullet. I dont use the die to seat the bullets as I thumb seat my bullets and shoot them without any neck tension with the bullet against the riflings. I have found that the Goex ffg I have used seemed to like about .30 inches compression in my 45/70 but that is with a Lee 450 and 500 grain bullets. You may find different with your bullet.
I don't have all the answers yet, but I hope this will help clear up some of the questions. There have been some that have given me their advice freely that has helped tremendusly. I'm more than happy to pass on what has worked for me.
