Guide to IMR Enduron Powders: 4166, 4451, 4955, 7977, 8933
IMR now offers five (5) Enduron powders: IMR 4166, IMR 4451, IMR 4955, IMR 7977, and IMR 8133. Shooters looking for readily-available alternatives to hard-to-find extruded powders should definitely check out the Enduron line-up. Precision shooters will find an Enduron option well-suited to most popular precision cartridge types. For example, IMR 4166 is a good replacement for Hodgdon Varget (commonly used in the .223 Rem, 6mmBR and .308 Win), while IMR 4955 is a fine substitute for H4831 (favored by F-Open shooters for the .284 Win and 7mm WSM cartridges).
Modern Powder Technology for Enhanced Performance
The technology in IMR’s Enduron line of powders provides four very important qualities that enhance both in-gun and downrange performance. First, these powders all feature chemistry that reduces copper fouling. Second, Enduron powders are all very temp-stable. Across the board, the Enduron line is very insensitive to temperature changes, which is important for both match shooters and hunters. Third, Enduron powders are designed for optimal load density. This helps attain low ES/SD in velocity and pressure, which translates to improved long-range accuracy and tight verticals. Finally, Enduron powders are environmentally-friendly, crafted from raw materials that are not harmful to the environment.
The Enduron Line-Up of Four Powders
IMR now offers four Enduron powders that cover a broad range of burn rates. They are suitable for a wide variety of cartridges, from small varmint cartridges all the way up to the .338 Lapua Magnum.
IMR 4166 possesses the fastest burn rate in the Enduron lineup. It is the perfect burn speed for cartridges such as .308 Win, 7.62mm NATO, 22-250 Rem and 257 Roberts. A versatile, match-grade propellant, IMR 4166 is comparable to Hodgdon® Varget.
IMR 4451 is a mid-range burn speed powder, ideally suited for cartridges such as .270 Winchester, .30-06 and 300 Winchester Short Magnum. This powder is comparable to Hodgdon H4350.
IMR 4955 is a medium burn speed powder, falling in between IMR 4451 and IMR 7977 in burn speed. It provides top performance in big game cartridges such as 25-06, 280 Remington and 300 Winchester Magnum. This powder is comparable to Hodgdon H4831.
IMR 7977 is a slower burn rate in the Enduron family. Loading density is perfect for magnums. This is a true magnum propellant yielding outstanding performance in .300 Winchester Magnum, 7mm Remington Magnum and .338 Lapua Magnum. IMR 7977 is comparable to Hodgdon H1000.
IMR 8133 IMR Enduron 8133 is the slowest burn rate in the Enduron family. Loading density is perfect for the very large magnums, including the 6.5mm and 7mm magnums. This is a true magnum propellant yielding outstanding performance in 6.5-300 Weatherby, .264 Win Mag, 28 Nosler and .300 Rem Ultra Mag, among other cartridges.
The Enduron Technology powders are available in one-pound (1 lb) and eight-pound (8-lb) containers from quality reloading retailers. Learn more about Enduron powders at www.enduronimr.com. For info on other IMR powders, visit www.imrpowder.com.
