I shoot a modern 12 gauge Pedersoli double ML which is choked IC and Light Mod. I use a .135 card wad over powder, 3/8" fibre wad, and a thin over shot wad made by slicing an over powder wad in to thirds with a razor blade. I honestly experience no problems getting everything past the chokes, and my theory is that the wads spring back to bore diameter once past the constriction. I get no blown patterns indicating blow-by, and the charge in the unfired barrel stays tight through several discharges of the other one. (I check the load for shifting when reloading the other barrel as a matter of course.) Patterns are nice and even, and dispersion is in keeping with the choke designations. Evidently I'm doing something wrong (or right).
