I'd submit that we need to be careful when speaking of "standard" loads available in the first couple decades of the 20th century. What we tend to forget is that the "standard" 12ga back then was chambered 2 5/8", and while 2 3/4" 12's were available with 1 1/4 oz of shot, I'm pretty sure such loads were NOT offered in 2 5/8" hulls. Checking my 1940 Shooter's Bible, which lists virtually every brand of American shotshell then manufactured, I cannot find a single 2 5/8" 12ga load with a heavier shot charge than 1 1/8 oz, or a heavier powder charge than 3 1/4 drams--and many of them were 3 drams, 1 1/8 oz. I suppose it's possible that heavier 2 5/8" 12ga loads were available 30 years earlier, but that seems unlikely.
