GUNS magazine did an article on St. Marks Powder Co a few years back. They manufacture most of the powder sold in the US, whether it's branded Hodgdon, Winchester , Alliant , IMR , etc. Used to be owned by Winchester/Olin , now owned by ATK/Alliant. H-110/W-296 is not the only Hodgdon/Winchester powder that is the same. HP-38 really is the same as W-231 , H-414 really is W-760 and so on.
GD-OTS Propulsion Solutions