Creation of IMR powders dates back again above 200 years when the corporation was originally Launched by E.I DuPont. Obtainable for use in many reloading apps, the IMR series of powder is trusted by reloaders all across the globe.IMR 4227 Powder in inventory now may be the imr 4227 Magnum Pistol Powder within the IMR lineup. If it states Magnum, 42