This calculator also makes it easy to visualize why Winchester reduced 00B diameter in the line to
.323" * with the 1963 introduction of the Mark V plastic collar and plastic buffer to the Super X Buckshot line.
* As reported by Jack O'Connor in The Shotgun Book (1965)
This game changing addition to the Super-X line was reported in the May 1963 issue of Guns Magazine:http://www.gunsmagazine.com/1963issues/G0563.pdf
Pictures on page 19
Write up on page 62