Well I had a few minutes spare so took the 12 down the garden to a piece of ply that I will be cutting off to put on top on my rifle rest (so I didn’t want to put holes through all of it).
Gun - the Hatsan Escort MPA with 24" barrel
Choke - screw in cylinder (I use the gun with slugs to)
Cartridges - home loaded 34gram, 9pellet, plastic non-cupped wad, clear overshot disk, roll crimp closed, 8.6mm shot ('00') .
I'd say the old adage of, " 1 inch of spread for every yard", is pretty accurate... give or take for the odd exception.
Black circle in each pattern is just roughly where I aimed. Shots taken at 5y, 10y, 20y, and just over 30y as that is the length of the lower garden where I shoot. The 'Max' figure is the furthest spacing that I could find center to center of each hole.
Ignore the crossed out hole as that was already drilled in the sheet.