Of all the Hype I have read over the years on the Square load I have as of yet to see evan an attempt at a logical explanation as to why this should make a more efficient load. Seems everyone who Exalts it "Blames" its use on the English. To the best of my knowledge neither Greener or Burrard mentioned it, so perhaps comes from some more obscure writer or from a later date.
I will say that if I desired to shoot a 1oz load, which I have on many occasions, I would much prefer to shoot it from either a 12 or 16 than from a 28 gauge. My reasoning here is the shorter column in the larger bores should result in a more efficient pattern without the necessity of all premium components.
Some of the best shooting I ever did in my life for upland hunting which included quail, some woodcock & rabbits being chased by beagles was using a 12ga @ 6lb 14oz using a low velocity, a bit over 1100 fps, 1oz load. The gun was a damascus J P Clabrough sidelock, pressure of the load was given in the manual as about 8K, never saw much need for a lower pressure. I like to keep- the max pressure as close to the breech as possible on the older guns which means faster powders & then load down to desired max.
