Production of IMR powders dates back above 200 many years when the organization was at first Launched by E.I DuPont. Readily available for use in several reloading apps, the IMR number of powder is reliable by reloaders all around the world.IMR 4227 Powder in stock now is the Magnum Pistol Powder in the IMR lineup. If it states Magnum, 4227 powder