Those 3 1/2 dram bulk smokeless/28-grain Ballistite dense smokeless 12-gauge loads were the hottest/heaviest offered by the factories. There were plenty of 2 1/2 dram, 2 3/4 dram, 3 dram, 3 1/8 dram and 3 1/4 dram loads being offered, and Ballistite as light as 20 grains and 1 ounce of shot, but North American shooters being how they are, you know plenty of the old boys were opting for the most they could possibly get!
And, in those days handloaders were often doing really scarry stuff!! I recall Bill Headrick did an article in The Double Gun Journal on a very high grade Parker Bros. hammer gun that the original order stated the purchaser wanted it to shoot a load of over 4 drams.
I just very carefully went through a 1903 Baltimore Arms Co. catalogue, and there is no mention in it anywhere of chamber lengths. There is a page of recommended Smokeless Powder Loads, but no mention of the length shell they should go in. They do state to only load black powder in brass shells and that for smokeless loads be sure your hulls have a high base if using dense powder and a low base if using bulk powder. The heaviest 12-gauge loads they recommend for Pigeon shooting is 3 1/4 drams of bulk smokeless powder and 1 1/4 ounce of shot or 26 grains of Ballistite and 1 1/4 ounce of shot. They recommend 2 3/4 or 3 dram, 1 1/8 ounce loads for field shooting.
The 1905 Philadelphia Arms Co. catalogue doesn't mention chamber lengths anywhere, but does give their recommended smokeless powder loads as being for 2 3/4 inch shells, and gives 3 1/4 drams with 1 1/4 ounce of shot. They don't mention Ballistite but do recommend 20 to 26-grains of Infallible. Under the DuPont Bulk smokeless poowder load, they state "If 2 7/8" or longer shells are used, use three or more 1/4 black-edge or express wads."
