If we take this at face value (making the assumption here) it would explain the decreased corrosiveness of BH209 because if it IS nitrocellulose-based it does not need to contain potassium nitrate or perchlorate as an oxidizer -- nitrocellulose contains its oxidizer intramolecularly (the oxidizing group is part of the same molecule, two molecules do not need to combine). Thus you won't get the potash and less need to swab the bore, explaining another characteristic of the powder.
It also makes the powder illegal for ML seasons in a large number of states.
Now this is not what the manufacturer claims it to be, right? So I'm just following the logic train in the post.
http://www.theopenrange.net/forum/index.php?topic=6150.0;highlight=blackhorn+209
I must mention that I have more than a bit of training in chemistry, and the spectrograph data in this article is provacative. I'm fairly suspicious that BH209 is, in fact, nitrocellulose based (Trail Boss is marketed as a smokeless powder). I wish I still had access to a GC/MS machine to confirm but I do not. If I ever get ahold of a bottle (never seen one yet) I may have to run some basic chemical analysis on it...
This article goes on to state that at least on individual claims to have found sulfur in BH209, which can turn corrosive in a humid environment.