Sloppy n KnightHawk , I believe it was them 2 fellars thought, that the 20 does better due to it being a stiffer wad because its a smaller diameter. thus its easier to get it to shoot better. They said to get the best patterns, it must be choked seriously tight to keep the petals from opening up.
Its deff not my go to gun, but if a friend needs to borrow a gun, or I need it in a pinch, I will use it.