Chuck's measurement agrees with mine. I no longer own a 101, but once had several. Most were right around .734 bore. For a time skeet-marked 101s (also Mirokus) lacked any constriction. I don't know why/how the Japanese developed this notion - probably from all the new, whiz-bang shotcup hype (or prophesying McIntosh - just kidding).
I owned a 4-bbl Diamond skeet and all 4 bbl sets had zero constriction.......not exactly what you want in .410.
I also owned a few 12 ga Winchoked 101s, and the skeet choke tubes invariably resulted in less than .002.
Sam
