Burrard had some pretty good coverage of shotsrtinging in his book, mostly done with the standard British game load shell; 12ga, 3de-1 1/16oz #6. A few things worthy of note though are I think;
#1; A very high percentage (I recall about 75%) of the shot load was found in the forward half of the string. The extreme of the "Tail" consisted of only a small % of the total & was likely the badly deformed pellets. Thus reduction of deformed pellets can result in a dramatic reduction of string length, but in actual effect nowhere near the "Lauded Improvement" to the load.
If you have made a 30% reduction in string length by moving up 5% of the shot a 30% increase in effectiveness of the load has not been made, just another "Mis-Use" of statistics.
#2; When he did test some 1Ľoz loads he was "Surprised" that he found no increase of stringing over the 1 1/16oz load. Thus an 18% increase of column length in the shell did "NOT" result in an 18% increase of the string in the air.
#3; His final conclusion & this with paper hulls loaded with card & felt wadding, sans any shot protector cups etc was;
Unless you are a specialized shooter, regularly shooting at birds in excess of 40 yds, flying in excess of 40 MPH at an angle of near 90° to the shot line "FORGET SHOTSTRINGING", its simply not an important factor.
With today's improved shells it is I feel sure even less so, & it doesn't have to be a WW Mark V in any case.
I think the most hilarious thing I ever read on the sq load was in a premier issue of a new rag devoted to shot-gunners some years back. A quite noted author wrote a "Resounding" article on the 28ga & promoted its Sq load effect. He defined the Sq load as being a shot load equal to a bore size round ball. He then correctly stated this could be found by dividing 16 by the gauge number & listed the 28 ga round ball as 16/28 as .57oz This is of course correct with rounding to two decimal places (plenty close for the purpose. But THEN he further stated this proved "conclusively" the 3/4oz load in the 28 was the "Perfect Sq Load". I don't know if he was really that Dumb or thought I was, but I learned way back down in Grammar School that .57 & .75 are not one & the same even though they do contain the same two digits, just rearranged. A sq load in the 28ga depending on whether one uses the equal column length to bore dia or the round ball equiv will be from just over 7/16oz for the first to just over 9/16oz for the latter, certainly not the 3/4oz load.
I can't really recall ever reading anyone whom I assessed to have reliable credentials who gave any advantage to the so-called sq load.
