Well Jones, here you go: From "Shotgun Stuff", a collection of Don Zutz's columns in Shotgun Sports magazine, in a chapter entitled "Waterfowl Loads and the 'New' Ballistics":

"Work done by Ed Lowry of Winchester and summarized in the December 1989 issue of American Rifleman magazine shows there can be a velocity loss of 50 to 100 fps during the first yard of free flight. For example, the new shotshell ballistics table worked out by Ed Lowry indicates a shot charge which reaches 1330 fps for a 3-foot chronograph reading needs an actual muzzle velocity of 1384 fps with BB's and 1447 fps with 7 1/2's to retain 1330 fps at 3 feet."

Ed Lowry was Winchester's ballistics guru for a very long time.