Bu7lk powders were often characterized by the grains weight of a 3 dram "Volume" measure. Thus original Schultz bulk shotgun smokeless was called a 42 grain power as a three dram black powder volume weighed 42 grains (3 drams of black weigned 82 grains). Neither were normally weighed but were simply dipped with a measure marked in drams. 1 dram was calculated at .115 cubic inches. Later EC bulk weighed 33 grains for the same 3 dram measure so was called a 33 grain powder.
As I recall from an article in the Rifleman many years ago Infallible & Unique had identical chemical formulations. They were round discs which I don't recall their diameter but were the same there. The Infallible discs were 3mm thick while those for Unique were thickened slightly to 3˝mm. Infallible thus would be slightly easier to ignite but would give slightly higher pressure for the same weight charge. In the card & felt/fiber wad days Unique with a 1oz load in 12 gauge required a very heavy wad pressure (on the order of 100 lbs) to ensure adequate ballistics.
