The use of 4Fg powder for priming is a fairly modern event. People knew that " fine " powder burned fast, and faster than coarse powders, as the Chinese were grining powder very small thousands of years ago for firecrackers. Even today, the black powder in firecracks is something like 7Fg powder, or flash powder, the same fine powder that was used in the 19th century by photographers to light up their subjects to get pictures on metal plates coated in silver- the degerrotype. Of course, lighting off flashpowder indoors proved to be too much of a fire hazard, and the photographers were saved by the invention and wide spread use of the electric Light bulb in the 1870s. It was in the late 1870s, and 1880s, that fine " Shutzen" rifles were brought to this country by German immigrants, in both ML and then in Breechloading cartridges, and the American Single Shot rifles became the rifle to have. Priming powder went, along with percussion caps. The cartridges used FFFg powder by and large, and that was what was sold by the manufacturers. I suspect that target shooters began screening their powders years before the factory began to do so, and market the powder in grades. In the shooting world, then as now, much of the Research and Development is done on the ranges, and not in the testing facilities at factories. That is why we have so many factory made cartridges today that began their lives as " wildcats ". Many of the smaller bullet making companies now in business today started with someone deciding he could make a better bullet in his own shop. And so it goes.
