Bernie,
I work for a muzzleloader company, and we recently got the following communication from Hodgdon:
"Triple Seven is about 15% more energetic than Pyrodex or black powder. Because of this a 130 grain volumetric charge of Triple Seven will be equal to 150 gr. Pyrodex or black powder. I would not suggest shooting over 130 gr. as the recoil is brutal - nothing takes this much killing."
This was in reference to our 209 guns, which will take a 150 grain charge of Pyrodex or 2F black powder, but this statement seems to go along with Hodgdon's original warnings to reduce charges by 15%. Initially, this warning applied to measuring by weight, but they are now apparently extending it to volumetric charges, as well. I'd certainly heed their warnings and reduce max charge by 15%, and limit my charge to 100 grains in a Remington.
Personally, I've had great results with Triple Seven. It burns cleanly, doesn't stink, is water-soluable and seems very consistent in terms of accuracy and velocity (I've chronographed Triple Seven loads several times). I can hardly wait to get my hands on some of the forthcoming Triple Seven pellets.
Mike