I'm curious about the history of this... they both seem to be marketed by Hodgdon.
Yes! Hodgdons markets both IMR and Winchester's line of powders.
Here is some History:
The history of IMR Legendary powders actually begins in 1802 when a young E.I. DuPont, who was forced to leave his native Paris during the French Revolution, built a black powder plant in Delaware. The plant was located on the former 95-acre Broom Farm. The farm was actually purchased under the name William Hamon, a friend, because at the time E.I. DuPont was not allowed to buy land until he became a U.S. citizen.
By the mid-1840’s the Gold Rush and industrial expansion ushered in the need for a better explosive than black powder. The twin 1845 discoveries of nitrated cotton and nitroglycerin began the transformation to a new explosives future. IMR powders started in 1892, ushering in the transition from black powder to smokeless powder. The earliest powders were designated “MR” meaning “Military Rifle”. These powders were numbered and ranged from MR#10 through MR#50-1/2. In the 1920’s an improved version of the powders were introduced. These “Improved Military Rifle” powders carried the “IMR” title in front of a four digit number.
Compared to modern standards, the calibers of the time were suited to faster burn rate powders. Thus the first of the “IMR” series of powders are on the faster end of the burn rate scale. The initial IMR powder was IMR4198, produced in the early 1930’s. This was followed by IMR4227 in 1934 and IMR4895 in 1941 (IMR4895 was the standard for military 30-06). Advances in ordnance drove the need for slower burn rate powders. In 1942, IMR4831 was developed for 20mm cannons. This was the slowest burn rate powder of its time. Following very quickly was IMR5010 for the 50 caliber Browning machine gun cartridge.
Originally, IMR powders were built in a facility at Carney’s Point, in New Jersey across the river from the black powder operations. This plant, built in the 1880’s, was a key provider of gunpowder to the U.S. military and its Allies during World War I. As the U.S. moved out of the Depression and headed towards World War II the need for increased capacity was satisfied through the construction of additional powder plants modeled after Carney’s Point. Amazingly, these plants in total shipped up to 1 Million pounds of gunpowder per day during World War II. In total, 2-1/2 billion pounds of smokeless powder was manufactured in these plants during the War. One of the locations of the newly constructed plants was Valleyfield, in Canada. This plant continues to be the primary supplier of IMR Legendary Powders today.
IMR powders maintained a competitive market position through the 1950’s in the reloading smokeless powder business. The company recognized the surge in the reloading market and produced their initial handloading guide in 1961. It was a modest effort limited to shotshell reloading. The 1960’s marked a very active reloading period with the invention of plastic shotshells and one-piece plastic wads. IMR introduced “Hi-Skor 700X” for target shotshell reloading in 1963.
The slowest burn rate IMR powder, IMR7828, was made available to reloaders in 1985. Prior this powder was only sold to commercial ammunition companies. The demand from reloaders for powders up to the task of modern cartridge and bullet designs brought about the availability of IMR7828. Today, IMR 7828 continues to be the standard for use in large-caliber and magnum performance rifle cartridges.
Hodgdon Powder Company purchased IMR® Powder Company in October 2003. Hodgdon Powder Company offices are located at 6231 Robinson in Overland Park, Kansas. IMR powders continue to be manufactured to the same exacting performance criteria and quality assurance standards that shooters have come to expect.
IMR truly represents Legendary powders – the IMR powders we reload today had their DNA established over 200 years ago. From World Wars I and II, to 1,000 yard benchrest competition, to your deer stand, IMR Legendary Powders are the standard all others attempt to follow.
