Wasn't Hodgdon's early 4831 reclaimed (pulled down) from loaded 20mm ammo, and both 4895 and Ball C reclaimed from loaded military .06 ammo?
When 4831 first became available it didn't have a number, but was referred to as "4350 data".
I'm an old (in my eighties) hand loader who recalls paying fifty two cents a pound for 4831 and less than a dollar a pound for 4895. Good old days.