Was just going through my old, old issues of Cartridges of the World. Noticed that many of the old nitro express cartridges were listed with the " grains of cordite " and then a load utilizing 3031 powder, almost exclusively. What's the deal on that!? Later editions have eliminated any reference to 3031.

Could it have been that some bright-spark figured that cordite & 3031 had the same burn rate?

Thanks