This link covers the Cordite subject well: http://en.wikipedia.org/wiki/Cordite
Before WW II (and somewhat beyond) propellant manufacture (and a lot of other things) was not as consistent as they are today, because of technology shortfalls. Nitro propellants typically had a greater batch to batch variance than is typical today. A batch of powder that met certain chemical and performance characteristics would be marked as "Canister Lot" for sale to small, custom ammo makers and the retail reloading public. Other powders that were made and intended to be for example "Bullseye or Unique", but did not meet "Canister Lot" specifications, would be sold to large ammo makers with a manufacturer's lab report for the batch. The large ammo maker (that had pressure test and chronograph equipment) would then have to determine the appropriate uses and charges for the batch of powder involved.