Trying to measure a molded plastic flexible wad isn't exact. You're talking about the diameter of the cup on the plastic wads?
Roughly measured a few new unfired wads.
12 ga. WAA 12R-----------.712" both at the driving band and at the base of the cup where the shot fills.
12 ga. Claybuster CB118-------.695 on the driving band---.703" base of shot cup
12 ga.Rem RXP 12-----.696" ----------------------.702" at bottom of cup
12 ga. Rem R12H------.702 both places
20 ga. Win WAA20-----.603" on the driving band---------.585" at base of shot cup
20 ga. Claybuster CB1078----------.590" both places
20 ga. Rem SP20-----------.595"- .602" both places.
These measurements are approximate. They can vary as much as .010" as they are not perfectly round.
