Well I have spouted it before, but will go again. Burrard covers the full particulars of that Maximum load. It was developed with the introduction of slower burning powders which allowed the heavier shot charge to be used without an increase of pressure. It was usually put up in the longer case with a fold crimp. The disadvantages were of course an increase in recoil, & if used continously an increase in the strain upon the action of the gun. An alternative is the "Low Velocity" load, again discussed in depth by Burrard wherein the increased shot charge is offset by a decrease in the powder charge & velocity of the load. This can be accomplished with normal recoil & stress & as long as an adequate shot size is used virtually no loss of effectivness. It really is a pity that no-one in the last 75 years has seen fit to publish a book delving into shotgun ballistics to the extent Burrard covered them. I have purchased several that received great press & their contents simply paled in comparsion.
