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).
The Japanese seemed to suffer from a certain amount of confusion where choke was concerned. The Parker Reproduction 28ga guns, which came out of the same factory as the 101, had constrictions like a 12ga if they had the 28" M/F barrels. I just measured one of those: .015/.035. Maybe those guys thought they only had so much constriction to use, so they saved it up on the 101 skeet guns and used it on the tight-choked 28ga Repros.
