John;
Being an American born 1938 of course all I know on this subject is what I have gleaned from reading over the years. What I have gathered here is the more or less standard black powder load for the nominally 2" gun was 3 Drams black with 1 1/8 oz shot. The early switch to smokeless was predominately with bulk smokeless which used the same volume of powder @ about half the actual weight. This gave a very slight reduction in recoil due to the lighter weight of the powder but not really enough to make a significant difference in the gun's weight. With the drop of the shot weight to 1 1/16oz & the increasing popularity of dense smokeless powders which again cut the weight of the powder approximately in half a significant reduction of gun weight could be accomplished without an increase in recoil. This was I highly suspect the reason for the continuing popularity o the lighter load. While it did prove to be adequate for its intended use, there is no evidence I am aware of that it was actually a "Better" load from an efficiency standpoint due to it being "Square".
