Is this a 12 gauge? If so, try 75 grains of FFg powder, one 1/8" thick OP wad, 1/3 cushion wad, lubed with moose milk, ( water, liquid detergent and water soluable oil- see member resources here for recipes) squeezed out, so that the cushion wad is damp but not dripping, then an OS card to give a hard flat surface to push the shot down the barrel, than 1 1/8 oz. shot, then another OS card.Run a lubed cleaning patch down the barrel when you seat that last OS card, to lube the barrel. If you rub lead off on a dry barrel, each succeeding pattern will be worse than the last, until you scrape or dissolve off the lead streaks in the barrel. The lube will let the pellets slide over the bore, rather than rub off lead the length of the barrel.
At 25 yds, that load should put about 50 % of the shot in a 30 inch circle. A good shotshell reloading manual will give the number of shot per ounce for whatever shot size you are using. for a 1 1/8 oz load, multiply that number times 1.125 to get the total number of pellet that you put down the barrel. Then count the holes. A cylinder bore gun should put all the shot in a 40 inch circle at 25 yards, but I find that optimistic with ML shotguns.
One real problem with your load is that the heavy wads pushing the shot follow the shot when it leave the barrel. There is a vacuum created by the shot and the wads are " sucked " into that space and actually bump the shot, causing it to spread wider than you want. ( Think of how race cars use the " draft " of a faster card to slingshot themselve around on the inside of turns to pass and overtake the lead car. The same aerodynamic forces are working with that shot column and those wads. By reducing the weight and size of the wads behind the shot, the wads drop away from the shot sooner, and are less likely to bump the shot.
The second method you can try uses only OS cards. You put 4 cards over the powder, then the shot, then 2 more OScards. Each of the cards has a pinhole poked into it with an awl, or needle, off center, and the cards are stacked so that none of the holes line up with the hole in the adjoining card. The holes let air out as you are loading them down the barrel, they are much easier to bend to get through any choke in the barrel, and air goes through the hole when the column of wads leaves the barrel to separate the cards, so they fall away quicker, than the above combination. If you lube the barrel as above, you again provide a slicker surface for the shot to pass over, you get less lead in the barrel, fewer pellets get flats on them, so they stay in the pattern longer, and the lube is there to soften the fouling that comes with the powder gases. The 4 cards used to replace the OP wad provide an excellent seal, so you don't have to worry about gases blowing by and ruining your shot pattern as the shot exits the barrel.
You do need to have a jag on your RamRod that is very close to the diameter of your barrels. In the case of barrels with choke, the jag has to be able to fit through the choke. That keeps the edges of the card from bending or folding, which would break the seal and let gases ruin all your efforts.
