I have a WW Greener 10ga. that is in great shape, I think it was built around 1875. I have tried just about every combination you can think of but so far the following load has given me the best results in this gun. I trim a Fed. case down to 2 7/8" I built a steel plug to go inside the case to use a triming guide and to keep the case mouth square. I size them in MEC press and prime with a Win. 209 primer. I load 4 1/2 Drams, that amounts to just a little over 120 grains of Fg on top of that I use a .090 card wad seated with about 90lbs. of pressure then a plastic wad cut out of a coffee can lid, this wad prvents the lube wad from soaking into the card wad and into the powder. As mentioned next is a 1/8 inch felt lube wad soaked in one of the black powder lubes. In order to get the Bismuth shot to pattern I cut the cushion off of a Remington SP10 wad and use just the shot cup this will hold about 1 3/8 oz of bismuth shot (my old shot measure shows 1 5/8 oz. which would have been lead) I also use shot buffer to help cushion the shot. Last I insert a Circle Fly over the shot wad and use a antique roll crimper to finish the round.
I have found that Bismuth needs a fairly tight choke to pattern well, also I can not get any of my guns to pattern with out a shot cup. Magtech is making brass hulls for reloading they work pretty well, I just wish that they would come out with a 10ga hull. The loading info I found suggests using Water Glass to seal the brass shells, I found out the hard way that this stuff hardens and falls out. I now use Fletch Tight which is an archery glue it works well and sticks to the brass holding the over the shot wad with no problem.
I am still trying to get my 16ga and 12ga guns to patten it just takes a lot of testing, if anybody has any tips on loading for these guns I would love to hear about it.
Shoot stright and keep your powder dry.
Bob