I little charge of smokeless under the black dates "Way" back. In their early days Lyman even offered a "Double Barreled powder measure which dropped alternate charges of the small smokeless one & the main Black one. I was always under the impression this was for the purpose of reducing fouling though & had little to do with ignition. Generally speaking Black is one of the easiest igniting of all small arms propellents, which is why restrictions are more severe on its storage, handling, shipping etc.
