There was a dealer in Sioux Falls who was selling 3100 as 4831 surplus. He was selling it in paper bags. I believe he bought a 55 gallon drum or two of surplus powder that was labeled 3100.
That was probably Trap And Field Supply. As a teen, I'd go there with my Dad. They had brown paper bags of powder. If you wanted a big quantity, they'd get it from a big cardboard drum. Robson Hardware also sold powder that way.
