Merchandise Overview: IMR 4227 PowderCreation of IMR powders dates back over 200 years when the corporation was originally Launched by E.I DuPont. Readily available for use in lots of reloading purposes, the IMR series of powder is trustworthy by reloaders all around the world.IMR 4227 Powder in inventory now may be the Magnum Pistol Powder in the