In the video, at 35 yards the shot string was approximately 8 ft long and took 0.0138 seconds from first to last pellet impact. A duck flying 35mph would move approximately 8.5 inches in the time it took from first to last pellet impact.
While the shot used was not buckshot, it indeed indicates that shot string plays a very marginal role in shotgunning. If buckshot pellets miss a deer it is due to the width and placement of the pattern.
This is not to dismiss your experiences, but to note there is another plausible explanation of your observations. As already noted, you limit your running shots to 20 yards and still shots to 40 yards - only when the deer is standing broadside. This self imposed limitation would maximize pellet penetration potential.
In shotgunning the compromise is always between on target pattern density (area of pellet strike) and sufficient penetration.
Last edited by RMcL; December 11, 2012 at 02:40 PM.