I agree with you about using plastic being somehow must wrong! However, when it comes to wounding game, or killing them cleanly, I would rather swallow my concerns and use the plastic, if it will improve the pattern. You might work on paper shotcups. So far, I have found that using a reduced diameter mandrill to wrap the paper around, using either a 20 ga. rod or 16, ga. rod, for a 12 ga. gun, then putting a dry cushion wad in one end before folding the paper over that end to make the " cup P seems to work. I then dip the tub in melted wax, to lock in the folds on the bottom, and wax the sides up about 1/2 inch. Adjust the total length of the cup with the amount of shot you are loading, then cut wings or petals in the front of the cup to act as an airbrake when it leave the muzzle. The length of the petals determine how long it takes to open and release the shot, which in turn seems to have a positive effect in tightening the groups. That is the point where I am still experimenting. I am using 3M Post-it Note paper, because it comes with a glue strip on one edge I can quickly use to seal the paper tube. On top of the shot cup I use an ordinary overshot card, pierced with an awl to let air in so I can seat it easily on top of the load. The wax seems to melt and keep the fouling soft, BTW. I decided not to lube the cushion wads, because that would make them heavier, and I didn't want the wad following the shot and punching a hole in the pattern. I have been mkaing do with 20 gauge materials for my 12, because I could not find the 16 ga. wads I needed when I went looking. I think staying as close to the bore diameter of the shotgun will make any paper shot cup more effective, less likely to tear in the barrel, and obviously do a better job of protecting the shot from rubbing against the sides of the barrel. So, making 2 complete turns around the circumference of my mandrill produces a strong cup, that does not seem to tear in the barrel.