Gm54-120
In the 1940s and 1950s DuPont "Bulk Smokeless" powder for shotguns was commonplace. It was used volume for volume as a substitute for black powder in shotguns. Its use, label, and marketing make it obvious that it was a black powder substitute in the volume for volume sense, which Triple Se7en is not.
I had no ideal... i was heavily into centerfires and reloading in the 50's-60's.... Did not know it even existed... I guess smokeless BP sub is not a new thought afterall.