
IMR 8133 Enduron
IMR Enduron 8133 is the slowest burn rate in the Enduron family. Loading density is perfect for magnums, contributing to superb uniformity. This is a… Read more about 8133 Enduron
Burn rate: 0.2Rifle calibers
The IMR (Improved Military Rifle) brand traces its origins to the early 19th century under the DuPont Corporation, a name synonymous with the development of high-performance gunpowder. E.I. du Pont, having arrived in America in 1800, established a gunpowder manufacturing facility by 1802 along the Brandywine River in Wilmington, Delaware. This site eventually evolved into the modern GOEX brand, now known for producing black powder.

DuPont quickly became a major supplier of military propellants, first seeing combat use in 1805 by U.S. naval forces during engagements off the coast of Algiers. By the time of World War I, DuPont was producing over 80% of the smokeless powder used by Allied forces. During World War II, demand for propellants soared—leading to the production of an astonishing 2.5 billion pounds of smokeless powder for Allied forces, reflecting the scale and importance of DuPont's role in global military supply.
The IMR brand itself was launched in the 1930s as part of DuPont’s push to provide more refined and consistent rifle powders for both military and civilian applications. Among the first powders introduced were IMR3031 (1934), IMR4064 (1935), and IMR4350 (1940)—formulations that remain staples in the handloading community to this day. IMR powders quickly earned a reputation for delivering the performance and consistency necessary to optimize rifle ballistics, becoming a go-to choice for generations of precision shooters and reloaders.
In 2003, the Hodgdon Powder Company acquired the IMR brand, uniting it with other prominent names such as Hodgdon, Winchester, and GOEX under one umbrella. Today, the IMR product line continues to offer a wide selection of powders engineered for handloaders, maintaining its status as a legendary name in reloading history.

IMR Enduron 8133 is the slowest burn rate in the Enduron family. Loading density is perfect for magnums, contributing to superb uniformity. This is a… Read more about 8133 Enduron
Burn rate: 0.2Rifle calibers

IMR Enduron 7977 is a slower burn rate in the Enduron family. Loading density is perfect for magnums, contributing to superb uniformity. This is a… Read more about 7977 Enduron
Burn rate: 0.6Rifle calibers

IMR 7828 SSC is a magnum rifle powder with exactly the same burn rate as standard IMR 7828 and uses the same data. However, due to the super short… Read more about 7828 SSC
Burn rate: 1.2Rifle calibers

IMR 4350 is a medium- to slow-burn rate propellant and is the number one choice for the new short magnums, both Remington and Winchester versions… Read more about 4350
Burn rate: 1.5Rifle calibers

IMR 4831 has a slightly slower burn rate speed than IMR 4350. It provides top velocities and performance with heavier bullets in medium-sized magnums.
Burn rate: 1.8Rifle calibers

IMR Enduron 4955 is a versatile, match-grade propellant with a mid-range burn speed that is in between IMR4451 and IMR7977. It is an extruded powder… Read more about 4955 Enduron
Burn rate: 2Rifle calibers

IMR Enduron 4451 is a versatile, match-grade propellant with a mid-range burn speed in the Enduron line. It is an extruded powder and is perfect for… Read more about 4451 Enduron
Burn rate: 2.4Rifle calibers

IMR 4064 is a medium-range burn speed powder and is one of the most versatile propellant in the IMR line, used for 223 Remington, 22-250 Remington… Read more about 4064
Burn rate: 4Rifle calibers

IMR Enduron 4166 is a versatile, match-grade propellant, with the fastest burn rate in the Enduron line. It is an extruded powder with a perfect burn… Read more about 4166 Enduron
Burn rate: 4.2Rifle calibers

Originally a military powder featured in the 30-06, IMR 4895 is extremely versatile as a medium burn speed propellant. From the 17 Remington to the… Read more about 4895
Burn rate: 4.4Rifle calibers

IMR 8208 XBR is an accurate-metering, super short-grained extruded rifle powder was designed expressly for match, varmint, and AR sniper cartridges… Read more about 8208 XBR
Burn rate: 4.8Rifle calibers

A medium burn speed propellant with many uses, IMR 3031 has long been a favorite of 308 Match shooters using 168-grain match bullets. It is equally… Read more about 3031
Burn rate: 5.2Rifle calibers

This fast-burning rifle powder gives outstanding performance in cartridges like the 222 Remington, 221 Fireball, 45-70, and 450 Marlin. It is also… Read more about 4198
Burn rate: 5.6Rifle calibers

IMR 4227 is a medium burn speed, magnum pistol propellant. If a pistol says Magnum, IMR 4227 is the choice for true magnum velocities and… Read more about 4227
Burn rate: 6Rifle calibersHandgun calibersSubsonic
Burn rate is a relative scale: lower values burn slower, higher values burn faster.
A cross-section of calculated IMR loads from our database, covering different calibers and bullets. Open a powder or caliber to see the full load tables.
Last updated: October 27, 2026
| Caliber | Bullet | Powder | Charge (gr) | Max. pressure (psi) | Muzzle velocity (fps) |
|---|---|---|---|---|---|
| .308 Win. | .308 | 190gr | Hornady Sub-X | IMR 4227 | 31.2 | 59,857 | 2,352 |
| 6.5 Creedmoor | .264 | 147gr | Hornady ELD Match | IMR 4831 | 41.3 | 57,986 | 2,667 |
| .223 Rem. | .224 | 55gr | Hornady Traditional/FMJ | IMR 4227 | 20.2 | 55,259 | 3,140 |
| 7 mm PRC | .284 | 175gr | Hornady ELD-X | IMR 7828 SSC | 66.5 | 61,337 | 2,923 |
| 6.5 PRC | .264 | 143gr | Hornady ELD-X | IMR 4350 | 51.7 | 61,467 | 2,861 |
| 6 mm GT | .243 | 105gr | Berger Hybrid Target | IMR 8208 XBR | Available with access license | 61,090 | 2,851 |
| .243 Win. | .243 | 100gr | Sierra SBT GameKing | IMR 4895 | Available with access license | 56,739 | 2,940 |
| .30-06 Spring. | .308 | 168gr | Barnes TTSX BT | IMR 8208 XBR | Available with access license | 58,450 | 2,762 |
| .22 Creedmoor | .224 | 85.5gr | Berger Long Range Hybrid Target | IMR 4831 | Available with access license | 64,411 | 3,192 |
| .338 ARC | .338 | 300gr | MAKER .338 ARC/Spectre Expanding Subsonic | IMR 4198 | Available with access license | 32,793 | 1,194 |
| .222 Rem. | .224 | 55gr | Sierra SBT GameKing | IMR 8208 XBR | Available with access license | 44,425 | 2,992 |
| .300 Win. Mag. | .308 | 178gr | Hornady ELD-X | IMR 4831 | Available with access license | 60,220 | 2,940 |
| 7 mm Rem. Mag. | .284 | 168gr | Berger VLD Hunting | IMR 4350 | Available with access license | 61,786 | 2,851 |
| .270 Win. | .277 | 145gr | Hornady ELD-X | IMR 4064 | Available with access license | 60,843 | 2,848 |
| 6.8 Western | .277 | 155gr | Barnes LRX BT | IMR 4895 | Available with access license | 64,905 | 2,923 |
| .300 Norma Mag. | .308 | 220gr | Berger Long Range Hybrid Target | IMR 8133 Enduron | Available with access license | 49,197 | 2,713 |
| .257 Roberts | .257 | 117gr | Hornady SST | IMR 4350 | Available with access license | 51,227 | 2,822 |
| .300 WSM | .308 | 190gr | Nosler AccuBond Long Range | IMR 4831 | Available with access license | 61,873 | 2,838 |
Choose your desired cartridge and bullet and proceed to the respective load page to customize your settings in the Personalized Load Calculator and get recipes for your specifications.
Looking for a specific cartridge? Browse the most requested calibers loaded with these powders: