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.
Larry, Thanks for this information on 3' vs. muzzle velocity.
I've been attempting to confirm how the published velocity data for the more common English & European loads is obtained. So far I have found references to CIP standard velocity measurement being both 1 meter & 2.5 meters but the only manufacturer supplied data is from Rottweil which states velocity @ 2.5 meters so I'm still unclear of the CIP standard for velocity testing.
Eley lists velocity @ v-1 which I take as @ 1 meter & I have E-Mailed Eley for a conformation of this.
Hull, GameBore & B&P simply state "velocity" however I did find a "Cartridge Review" article in an old Sporting Clays magazine in which the writer stated that Hull & B&P velocities were measured @ 1 meter but this needs conformation from the manufacturers.
If 1 meter is the standard for CIP, comparison to SAAMI loads obtained @ 3' should be meaningful but this conflicts with some test data published over on Shotgun World that showed some of the English loads being slower than the published data when tested by SAAMI 3' standards. You have to wonder if some manufactures are taking CIP & SAAMI data & making a conversion back to muzzle velocity in an effort inflate the velocity figures for sales appeal.
One would think that cartridge manufactures would clearly state the distance @ which the of velocity their products are measured & especially if it deviates from the testing standards in place for the country where it is manufactured.
