Stan;
Your reply re-enforces the point I was making. As a conscientious shooter you do not take those shots at doves over 40 yds, exceeding 40 mph @ 90 to your shot line with your .410. You instead work at picking shots within its capabilities. I applaud you for this.
OLd Colonel;
Note I did not write the definition of a square load, merely stated what it is. The definition "IS" that the length of the shot column is equal to the diameter of the bore. neither 7/8oz in the 20 or 1 oz in the 16 meets this criteria. Both are in my opinion better loads for the gauge than the actual square load, but They Ain't Square.
In a bore of nominal size & no shot collar 7/8oz in a 20 stacks up to about .84", 1oz in the 16 about .85" & 1oz in the 12 about .86" All of these you will not have very similar column lengths, all are efficient loads for the gauge & all were able to be balanced with the early smokeless propellants. All have been loaded with great success for well over a century but none of them are square.
