Some guns do better than others. It's all experimentation. Some loads in a cylinder bored gun are not good enough at 15 or 20yards.
Post-it note sleeves work for some, not for others.
These worked in the 1800's.
Since they aren't available today, some shooters have found the use of paper wraps do work. Some have used bank coil wrappers, stopped in each end with a wad.
Some have found these to shoot too tightly close in, so have cut slits in the paper to allow the shot to spread more quickly.
I will note here, that several "Colours" of shot ctgs. were used, depending on the expected range- from cylinder bored guns.
The Green (papered) one, out to 50 or 60 yards, acted as a slug, noted for deer or wolves, yet were for shooting ducks past 90yards, where the shot finally spread.
Other colours, red and yellow were for closer range shooting on ducks.
There is a good note in "Firearms of the American West" of a contest held in St. Louis area between an English Sportsman, here for hunting. He had a small (little pistol according to the fellow he shot against) SxS 14 bore shotgun cylinder choked gun in a patterning contest between himself and a local chap who had a 12 bore with 48" tubes, also non-choked. This fellow was a market hunter for the area.
The target was a 4" x 7" card of paper placed at 75yards. The local chap shot first, and was pleased with the 4 hits he had on that card of paper.
The Englishman "pulled his shot fired off the powder and reloaded his gun with the green ctg. He fired at the mark and put 28 holes through it. 4" x 7" - amazing.