I would bet it's the same powder as RL-15, but have an assignment for magazine that involves shooting various powders to find out how they vary from lot-to-lot, or in various forms over the years, or to find out whether rumors of some powders being the same under different names are true or not.
Among the powders that will be tested are RL-15 and 203B, and I have two different lots of 203B from several years apart to see how they vary as well. Norma admits some of their powders are "very similar" to Alliant powders, but also claims they're more consistent.
Lot-to-lot variation can be considerble. Just look at data for H414 and W760 over the years. They're the same powder and have been for a long time (Hodgdon confirmed as much after they acquired the rights to the "Winchester" powders), but loading data from other companies will differ because of lot variation.
