Contributor to Chuck Hawks' site states that the 1939 German standard for "minmax" tolerance of 12 ga. bore is .716 to .732" so these tubes are on the minimum end of the range and should produce very good velocity with any given load. Turns out they're not so far off the European .725 "nominal" 12 bore diameter about which I had no clue despite having measured some Belgian Brownings.

jack