HuntnShoot,
Actually, there are three "kinds" of 4227, though it's somewhat confusing. H4227 is one of the Extreme temp-resistant powders, is made by Australian Defence Industries--but ADI also makes some IMR4227, though there are conflicting reports about how that differs from H4227. Hodgdon told me it was made to the same specifications as the IMR4227 made in Canada, but I have found reports on the Internet where ADI claimed it was the same as H4227. The Canadian IMR4227 is supposedly similar to the powder made by DuPont in the U.S. for many years.
