Take a 1/2" cushion wad, and cut it into quarters. Then put some vegetable oil- olive oil if you must!--- in a shallow dish, or the lid of a jar. Roll the edges of the wads in the oil so that the entire circumference of the wad is coated with oil about 1/16-1/8" from the edge. Set the wads aside on paper towels to absorb the excess oil.
Bob Spenser's Black Powder notebook can be found here:
http://home.insightbb.com/~bspen/
That is where you will find both his article on his loads, and the V.M. Starr article you should read. V.M. Starr is considered the Father of modern BP shotgun shooting, as He kept the sport alive, and wrote about loading techniques back in the 30s, 40s, and 50s, when the NMRLA was still struggling to grow. He built, and worked on old shotguns, fixing them for people. He also did jug-choking when there were few people alive who had any idea how it was done.
If you use plastic shotcups, remember to grease them or grease the bore after seating them on your wads. Otherwise, you will get plastic build up on the inside of the bore, and it will require modern solvents, and bore brush work to remove the residue. If you shoot exposed lead shot in the gun, the lead will rub off against the bore, leaving lead streaks. They do interfere with the seal of the wads, and ruin patterns. Grease the bore with a lubed cleaning patch in front of your cleaning jag, when you run those OS cards down on top of the shot load in the gun. The Grease will let the shot glide OVER the steel bore, and leave less, or no lead streaks.
A secondary benefit it more shot pellets making it to your target, as the flattened shot pellets that rubbed off lead against the bore drop out of the pattern in the first 20 yards in front of the muzzle.
If you put up paper at 15 yards- 3 ft. square-- and shoot a pattern at it, you will often see pieces of shot below the main pattern, that, on close examination, leave squared sided holes in the paper. Greasing the bore after seating your shot load and OS cards will eliminate most of this.
You will also get better patterns at longer distance, if you reduce that powder charge to 80 grains, instead of the 90 grains you are using. For more impact energy on game, simply use the next size larger bird shot- ie. #5 instead of #6 shot, for example. Pellet energy is what delivers the killing power on game, and #6 shot will be good out to 30 yards. But in a cylinder bore gun, #5 shot will extend your power out past 35 yards.
If you have a choked barrel on your shotgun, then, you may be able to take advantage of the faster velocity you get from using more powder, depending, of course, on the degree of choke, and the load used. :thumbsup: