IMR 4831 is a legendary slow-burning extruded propellant that has served as a staple on reloading benches for decades. Originally produced by DuPont and now a premier offering in the IMR Powder lineup, IMR 4831 was specifically developed to bridge the gap between medium-slow powders like IMR 4350 and the very slow magnum propellants. It is renowned for providing top-tier velocities and exceptional accuracy in a wide variety of medium-capacity magnums and large-bore standard cartridges, particularly when paired with heavy-for-caliber bullets.
- Main Application: Medium-sized magnum cartridges and high-capacity standard rifle rounds.
- Key Advantage: Exceptional case fill and high velocity potential for heavy projectiles.
- Burn Rate: Slow rifle propellant.
- What This Guide Covers: Detailed technical profile, temperature stability analysis, a 4-way competitive market comparison, and comprehensive component compatibility.
Best For: Hunters and precision shooters seeking maximum velocity from cartridges like the 270 Winchester and 300 Winchester Magnum.
Powder Description & Technical Profile
IMR 4831 is a classic “stick” or extruded powder characterized by its cylindrical grains. Unlike modern “short-cut” versions of similar powders, IMR 4831 retains its traditional grain length, which contributes to its high bulk density of approximately 881 grams per liter (55 lbs/ft³). This density is a critical factor for reloaders, as it allows the powder to occupy a significant portion of the case volume, often resulting in load densities that exceed 90%.
The expert “feel” of IMR 4831 is often described as providing a “progressive push.” Because it is a single-base powder (primarily nitrocellulose), it produces a predictable and linear pressure curve that is highly suited for cartridges with relatively large cases and small bores. This internal ballistic profile ensures that the bullet is accelerated consistently down the barrel, minimizing the peak pressure spikes often associated with faster-burning propellants in the same caliber class.
Pros & Cons
- Pros:
- Delivers world-class velocities in the 270 Winchester, often exceeding 3,000 fps with 130 grain bullets.
- Provides excellent loading density, which promotes uniform ignition and consistent vertical spreads.
- Extremely versatile across a range of calibers from 243 Winchester to 300 Winchester Magnum.
- Proven track record for match-grade accuracy in vintage and modern rifles alike.
- Cons:
- Traditional long-grain sticks can “bridge” in some volumetric powder measures, requiring careful monitoring.
- Exhibits higher temperature sensitivity compared to modern “Extreme” or “Enduron” series powders.
- Can be difficult to meter with high precision in small-necked cases without a high-quality dispenser.
Burn Rate and Temperature Stability
In the relative burn rate hierarchy, IMR 4831 occupies a specific niche. It is slightly slower than IMR 4350 but notably faster than Hodgdon H4831 or Alliant Reloder 22. This positioning makes it the ideal “accelerant” for reloaders who find that IMR 4350 reaches maximum pressure before achieving the desired velocity, or for those who find that H4831 fills the case too much before reaching optimal pressure levels.
Temperature sensitivity is the primary area where IMR 4831 shows its traditional heritage. Professional testing and real-world field reports indicate that IMR 4831 can experience a velocity shift of 60-100 fps across a 100-degree Fahrenheit temperature swing. For instance, a 7mm Remington Magnum load developed at 75°F may drop approximately 50-70 fps when used in -15°F hunting conditions. While this is acceptable for most hunting scenarios, it requires the long-range shooter to maintain updated ballistic charts for different seasonal conditions.
Stability Table
| Powder | Type | Temperature Sensitivity | 100°F Swing FPS Variation |
| IMR 4451 (Enduron) | Extruded (Stable) | Very Low | 20-30 fps |
| IMR 4831 | Extruded (Single-Base) | Moderate | 60-100 fps |
| Alliant Reloder 22 | Extruded (Double-Base) | Moderate-High | 120-140 fps |
Powder Comparison
To select the best propellant for your specific rifle, it is helpful to compare IMR 4831 with its closest market competitors.
- IMR 4350: This is the faster-burning sibling to IMR 4831. While IMR 4350 is excellent for lighter bullets in the 30-06 Springfield, IMR 4831 typically provides better performance and higher case fill when moving to 180 grain or 200 grain projectiles.
- Hodgdon H4831SC: Often confused with IMR 4831, the Hodgdon version is actually slower burning. H4831SC is an “Extreme” powder, meaning it is significantly more stable in varied temperatures. However, IMR 4831 often produces slightly higher velocities in medium magnums because its burn rate is more aggressive.
- Alliant Reloder 22: This is a double-base powder that is slower than IMR 4831. While Reloder 22 can achieve higher absolute velocities in large magnums, IMR 4831 is often preferred for its cleaner burning characteristics and its better fit in standard-length cases like the 280 Remington.
- IMR 4451: This is the modern “Enduron” equivalent to the 4831 burn speed. It features copper fouling eliminators and extreme temperature stability. While more technologically advanced, many reloaders stick with IMR 4831 because of its established load data and consistent performance in older rifle barrels.
Comparison Table
| Powder Name | Burn Rate | Density (g/L) | Primary Cartridges |
| IMR 4350 | Medium-Slow | 850 | 243 Winchester, 30-06 Springfield |
| IMR 4831 | Slow | 881 | 270 Winchester, 300 Win Mag |
| Hodgdon H4831SC | Slow | 910 | 25-06 Remington, 7mm Rem Mag |
| Alliant Reloder 22 | Slow | 930 | 300 Weatherby Magnum, 264 Win Mag |
| IMR 4451 | Slow (Stable) | 890 | 6.5 Creedmoor, 30-06 Springfield |
Applications and Performance
The performance of IMR 4831 is most prominent in “overbore” cartridges where the case capacity is large relative to the bore diameter. In the 25-06 Remington, IMR 4831 is widely considered one of the best possible choices for 100-120 grain bullets, providing the necessary gas volume to maximize the long barrel lengths typical of that caliber. Similarly, in the 300 Winchester Magnum, IMR 4831 allows for high-velocity loads with 165 and 180 grain bullets without completely compressing the powder charge to the point of bullet deformation.
Regarding cleanliness, IMR 4831 is a traditional single-base powder that burns relatively cleanly at high pressures. However, if used in low-pressure “starting” loads, it may leave behind more sooty residue and unburned kernels. Metering with IMR 4831 requires a consistent technique; because the grains are long, they can be “cut” by the edge of a powder measure’s drum, which might lead to slight weight variations. For precision work, many reloaders prefer to throw a slightly light charge and trickle the final few tenths of a grain to ensure perfect uniformity.
Recommended Cartridges and Applications
IMR 4831 has been a top performer in these calibers for decades. The following links provide detailed guides for each cartridge where IMR 4831 excels.
| Cartridge | Primary Application |
| 270 Winchester | High-velocity deer hunting with 130-150 grain bullets. |
| 25-06 Remington | Long-range varmint and open-country pronghorn hunting. |
| 300 Winchester Magnum | Maximum velocity with 165-190 grain heavy hunting bullets. |
| 7mm Remington Magnum | Balancing high muzzle energy with excellent case fill. |
| 6.5×55 Swedish Mauser | Precision target and moose hunting with 140 grain projectiles. |
| 30-06 Springfield | Heavy-bullet elk loads (180-220 grains) requiring a slow burn. |
| 243 Winchester | Driving heavy 100 grain bullets for long-range deer hunting. |
| 6mm Remington | Traditional high-velocity varmint and predator control. |
| 280 Remington | Optimizing the performance of 140-160 grain hunting bullets. |
| 257 Roberts | Enhancing performance in modern +P rifle actions. |
Bullets
The slow-burning nature of IMR 4831 requires bullets that provide enough neck tension and bore resistance to ensure a complete and consistent burn.
| Bullet Model | Recommended Weight Range | Best Application |
| Nosler Partition | 115-200 grains | Big game hunting with high terminal reliability. |
| Hornady Interlock | 100-154 grains | Reliable expansion for standard hunting distances. |
| Sierra GameKing | 100-180 grains | Accurate boat-tail bullets for long-range game. |
| Nosler Ballistic Tip | 95-180 grains | High ballistic coefficient for open-country shooting. |
| Berger VLD Hunting | 130-190 grains | Match-grade precision for extreme distance hunting. |
| Hornady Interbond | 130-154 grains | Bonded core for maximum weight retention. |
| Nosler RDF | 130-140 grains | Pure target and competition precision in 6.5 calibers. |
Primers
Lighting a large column of extruded IMR 4831 requires a consistent and powerful ignition source. While standard primers are often sufficient for cartridges like the 270 Winchester, magnum primers are frequently recommended for larger magnums to ensure a complete burn of the slow powder charge.
| Primer Model | Brand | Type | Best Application |
| CCI #200 | CCI (U.S.) | Large Rifle | Standard cartridges like 270 Winchester. |
| Federal #210 | Federal (U.S.) | Large Rifle | Benchrest-quality consistency for standard cases. |
| Winchester WLR | Winchester (U.S.) | Large Rifle | High-intensity standard primer for reliable ignition. |
| CCI #250 | CCI (U.S.) | Large Rifle Magnum | Best for cold weather and large magnum charges. |
| Federal #215 | Federal (U.S.) | Large Rifle Magnum | The gold standard for heavy magnum rifle loads. |
| Remington #9 1/2 | Remington (U.S.) | Large Rifle | Traditional choice for 30-06 and 270 loads. |
| RWS 5341 | RWS (International) | Large Rifle | Exceptional European precision for high-end rifles. |
| Fiocchi LRM | Fiocchi (International) | Large Rifle Magnum | Reliable ignition for high-volume magnum shooting. |
| Murom KVB-7 | Murom (International) | Large Rifle | Consistent performance with a hard cup for high pressures. |
Conclusion and Expert Verdict
IMR 4831 remains a quintessential propellant for the high-performance rifle shooter. It offers a level of velocity and case fill that many modern propellants struggle to match, particularly in the venerable 270 Winchester and 300 Winchester Magnum. While it does require the reloader to be mindful of ambient temperatures and potential metering variances, its reputation for accuracy and “linear” performance makes it one of the most trusted powders in reloading history. If you are looking for a powder that “just works” in large-capacity standard and magnum rifles, IMR 4831 is a mandatory addition to your supply.
Expert Pro Tip: Because IMR 4831 is a long-grain extruded powder, it can be sensitive to “crunching” or kernel breakage during heavy compression. If your load requires a compressed charge (often seen in the 300 Winchester Magnum), use a long drop tube to settle the powder naturally in the case. This increases the effective loading density and prevents the bullet from being pushed back out by compressed kernels, ensuring consistent neck tension and improved accuracy.
