Published: 2026 | Last updated: May 2026
IMR 4831 is a slow-burning, single-base long-cut extruded powder with a pedigree that traces directly to the DuPont powder works and represents one of the oldest continuously used slow-rifle formulations in North American reloading. Originally developed for 270 Winchester and large-capacity standard rifle cases, it earned its reputation over decades in the 25-06 Remington, 280 Remington, 30-06 Springfield with heavy bullets, and 300 Winchester Magnum at standard bullet weights. It is now distributed by Hodgdon Powder Company as part of the IMR lineup.
The powder occupies a specific burn rate position that requires careful orientation: it sits between IMR 4350 (faster) and Hodgdon H4831SC (faster) on the burn rate chart. A critical and frequently confused point: despite the shared “4831” name, Hodgdon H4831SC burns faster than IMR 4831 – not slower, as often assumed. The name similarity has caused more than a few dangerous substitution errors, and the distinction is addressed directly in this guide.
IMR 4831 carries no temperature-stabilizing additive package – neither Extreme series chemistry nor Enduron technology. Its temperature sensitivity (approximately 60-100 fps across a 100°F swing) is the honest trade-off for a traditional DuPont formulation that pre-dates modern stabilizer technology. For a reloader who values maximum published data coverage, proven field performance, and does not need Extreme or Enduron stability, it remains a fully capable slow-rifle powder.
This article is based on published manufacturer specifications, established load data, and documented field reports. Specifications and performance figures can vary between lots, rifles, and conditions. If you have loaded IMR 4831 in practice – leave a comment below: real-world experience from the reloading bench is what separates verified data from manufacturer claims.
Powder Description and Technical Profile
IMR 4831 is a single-base, long-cut cylindrical extruded powder. The single-base formulation – nitrocellulose without nitroglycerin – produces the clean-burning characteristics and moderate temperature stability that single-base extruded powders consistently deliver.
The long-cut grain geometry is the defining practical limitation at the loading bench. Traditional long-grain sticks:
- Bridge across measure drum apertures, disrupting smooth flow
- Shear at the drum edge during cycling, producing broken grains of variable size
- Settle inconsistently in the case, making drop tube technique more important than with short-cut alternatives
Charge-to-charge variance from standard volumetric measures is ±0.3-0.5 grains – the same limitation that the SSC reformulation addressed for IMR 7828. For a reloader who hand-weighs or auto-dispenses every charge, this variance disappears. For progressive press production, the long-grain geometry makes precise IMR 4831 loading more demanding than short-cut or ball alternatives.
Bulk density is approximately 0.880-0.890 g/cc (55 lbs/ft³). This produces good but not exceptional case fill – at working charge weights in 270 Winchester with 130-150 grain bullets, case fill runs 88-96%, adequate for consistent ignition and position sensitivity resistance without reaching compression territory in most loads.
The progressive linear pressure curve is the property most discussed in the context of IMR 4831’s accuracy reputation. Pressure builds steadily through the working range without the sharp spike that can appear with faster powders in the same cartridges. For precision load development, this linearity means pressure signs appear gradually as charge weight increases, giving the reloader clear feedback before reaching dangerous territory.
The long drop tube technique mentioned in the original article is specifically important for IMR 4831 near maximum charges in 300 Winchester Magnum and similar large cases. A 6-10 inch drop tube allows long sticks to settle into the case naturally through gravity rather than being compressed against each other by the seating die. This increases effective case fill by approximately 2-3% and prevents the inconsistent kernel arrangement that causes compressed load variation.
Strengths:
- Deep published data library from decades of North American reloading manual coverage – virtually every cartridge in its application range is thoroughly documented
- Single-base clean burning – less carbon residue at high pressure than double-base alternatives
- Progressive linear pressure curve – gradual pressure development produces forgiving load development behavior
- Proven field record in the classic hunting cartridges where its reputation was built
- Good case fill in the medium-to-large capacity standard and magnum cases where it operates most efficiently
- DuPont heritage with lot-to-lot consistency from long-established manufacturing
Limitations:
- Long-grain geometry produces ±0.3-0.5 grain volumetric variance – hand-weighing or auto-dispensing required for precision work
- Temperature sensitivity of 60-100 fps per 100°F swing (approximately 0.6-1.0 fps/°F) – substantially more sensitive than Extreme series or Enduron alternatives; seasonal load recalibration required for long-range applications
- The “H4831SC is slower” myth – this common assumption is wrong and dangerous (see dedicated section below)
- Single-base lower energy density than double-base alternatives at the same burn rate – Alliant Reloder 22 and Alliant Reloder 19 produce more velocity at the same pressure in their respective applications
- Low-pressure starting loads burn dirtier – as with most single-base slow powders, reduced loads below approximately 80% of maximum produce noticeably more residue and occasional unburned kernels
Technical Characteristics
| Property | Specification |
|---|---|
| Manufacturer | IMR Powder (Hodgdon Powder Company) |
| Heritage | DuPont original formulation |
| Type | Single-Base Long-Cut Extruded |
| Bulk Density (g/cc) | ~0.880 – 0.890 (55 lbs/ft³) |
| Grain Shape | Long Cylindrical |
| Coating | Graphite and Stabilizers |
| Burn Rate Category | Slow Rifle |
| Temperature Sensitivity | ~0.6-1.0 fps / °F (60-100 fps per 100°F swing) |
Critical: IMR 4831 vs. Hodgdon H4831SC – The Name Confusion
The shared “4831” designation between IMR 4831 and Hodgdon H4831SC has generated more reloading confusion than almost any other naming collision in the industry. The original article’s statement that H4831SC is “slower burning” than IMR 4831 is incorrect and potentially dangerous.
The actual relationship:
| Powder | Type | Burn Rate | Density (g/cc) | Stability |
|---|---|---|---|---|
| Hodgdon H4831SC | Single-Base Extruded | Faster than IMR 4831 | 0.875 | ~0.3 fps/°F (Extreme) |
| IMR 4831 | Single-Base Long-Cut | Reference | 0.885 | ~0.6-1.0 fps/°F (Standard) |
| Alliant Reloder 22 | Double-Base Extruded | Similar-Slower | 0.930 | ~1.6-1.8 fps/°F |
Hodgdon H4831SC burns faster than IMR 4831 – typically 2-4 positions faster on the Hodgdon relative burn rate chart. Applying H4831SC charge weights to IMR 4831 at the same cartridge could produce elevated pressure because IMR 4831 burns slower than the H4831SC data assumed. Develop each powder from its own published data.
The two powders were never equivalent. They share a name coincidence, not a formulation connection. H4831SC is the Hodgdon Extreme series powder at a slightly faster burn rate position, with ~0.3 fps/°F temperature stability. IMR 4831 is the traditional DuPont slow-rifle formulation with standard temperature sensitivity and a different burn rate.
Temperature Stability – Practical Impact
60-100 fps per 100°F swing (0.6-1.0 fps/°F) places IMR 4831 in the moderate sensitivity range – comparable to Accurate 4350 and better than double-base alternatives like Alliant Reloder 22 (1.6-1.8 fps/°F). A practical hunting example:
A 7mm Remington Magnum load developed at 75°F producing 2,950 fps will produce approximately:
- At -15°F (90°F colder): 2,950 – (90 x 0.8) = approximately 2,878 fps – 72 fps slower
- At 400 yards: approximately 2 inches of additional drop vs. summer zero
For hunting shots at 300-400 yards on elk and deer, this variation is within the practical margin. For precision long-range shooting at 600+ yards across seasons, a temperature-corrected firing solution is needed.
| Powder | 90°F Swing | At 400 yards | At 600 yards |
|---|---|---|---|
| IMR 4451 Enduron | ~14-27 fps | <0.5″ | <1″ |
| Hodgdon H4831SC | ~27 fps | ~1″ | ~1.5″ |
| IMR 4831 | ~54-90 fps | ~1.5-2.5″ | ~3-4″ |
| Alliant Reloder 22 | ~144-162 fps | ~4-5″ | ~7-8″ |
Burn Rate Comparison and Competing Powders
| Powder | Type | Density (g/cc) | Key Character |
|---|---|---|---|
| Hodgdon H4831SC | Single-Base Extruded | 0.875 | Faster – Extreme stability |
| IMR 4451 Enduron | Single-Base Short-Cut | 0.909 | Faster – Enduron stability + decoppering |
| Hodgdon H4350 | Single-Base Short-Cut | 0.860 | Faster – Extreme series benchmark |
| IMR 4831 | Single-Base Long-Cut | 0.885 | Reference |
| Alliant Reloder 22 | Double-Base Extruded | 0.930 | Similar-Slower – higher velocity, less stable |
| Norma 204 | Single-Base Extruded | 0.860 | Similar – European single-base |
| Vihtavuori N150 | Single-Base Extruded | 0.910 | Similar – European single-base |
vs. Hodgdon H4831SC: H4831SC burns faster than IMR 4831 and belongs to the Extreme series with ~0.3 fps/°F stability. It produces comparable or slightly higher velocities than IMR 4831 in many applications from its faster burn, and it has the seasonal stability advantage. Charge weights are not interchangeable. For a reloader starting fresh with 270 Winchester or 25-06 Remington, H4831SC is the more seasonally stable modern choice. For a reloader with established IMR 4831 loads who is satisfied with the temperature protocol, there is no compelling reason to switch.
vs. IMR 4350: IMR 4350 burns faster than IMR 4831 and is better matched to lighter-weight bullets in medium-capacity cases like 30-06 Springfield with 150-165 grain bullets and 243 Winchester with standard weights. IMR 4831 becomes more appropriate when bullet weight increases and effective case volume decreases – for 180-220 grain 30-06 Springfield loads and 165-190 grain 300 Winchester Magnum loads, IMR 4831’s slightly slower burn is a better pressure-development match.
vs. IMR 4451 Enduron: IMR 4451 Enduron is a more technically capable modern alternative at a faster burn rate – Enduron temperature stability (<15 fps per 100°F), integrated decoppering chemistry, and superior short-cut metering. For new load development in IMR 4831’s primary cartridges, IMR 4451 is worth developing alongside and choosing if the stability premium justifies the cost. For existing verified IMR 4831 loads that are performing well, the Enduron premium may not provide sufficient field-use benefit to justify a complete redevelopment.
vs. Alliant Reloder 22: Reloder 22 is a double-base powder that burns slower than IMR 4831 and produces higher velocity from its nitroglycerin energy content – but at 1.6-1.8 fps/°F temperature sensitivity, it is significantly more thermally variable. For maximum velocity in 300 Winchester Magnum and 7mm Remington Magnum with full temperature protocol acceptance, Reloder 22 is a velocity-priority choice. For single-base cleanliness and better seasonal consistency, IMR 4831 is more appropriate.
Recommended Cartridges and Applications
IMR 4831 is best suited to medium-to-large capacity cases with standard to heavy-for-caliber bullets where its progressive pressure curve produces accurate loads and adequate case fill.
| Cartridge | Bullet Weight Range | Notes |
|---|---|---|
| 270 Winchester | 130-160 gr | Classic home territory – excellent fit |
| 25-06 Remington | 100-120 gr | Varmint through deer |
| 30-06 Springfield | 165-220 gr | Heavy-bullet applications |
| 280 Remington | 140-175 gr | Mountain hunting loads |
| 7mm Remington Magnum | 154-175 gr | Standard hunting weights |
| 300 Winchester Magnum | 165-190 gr | Standard hunting weights |
| 6.5×55 Swedish Mauser | 140-160 gr | Hunting and target |
| 243 Winchester | 95-105 gr | Heavy-bullet deer loads |
| 6mm Remington | 95-105 gr | Heavy varmint and deer |
| 257 Roberts | 100-120 gr | Near-maximum loads |
The 270 Winchester is the application most closely identified with IMR 4831’s historical reputation. With 130-grain Nosler Ballistic Tip or Sierra GameKing bullets in a 24-inch barrel, IMR 4831 produces velocities in the 2,950-3,050 fps range at appropriate pressures – near the practical velocity ceiling for this cartridge with these bullets. The powder’s burn rate is specifically well-matched to the 270 Winchester case volume at these bullet weights.
The 30-06 Springfield with 180-220 grain heavy bullets is the other classic application. With standard 150-165 grain bullets, IMR 4350 is typically better matched. When bullet weight increases to 180 grain and above – for elk, moose, and large-game hunting – the longer, heavier projectile reduces available powder space and shifts the optimal burn rate toward slower. IMR 4831 becomes the better fit at these heavy-bullet 30-06 Springfield loads.
Practical Loading with IMR 4831 Long-Cut Grains
Because long-grain geometry makes volumetric production metering imprecise, IMR 4831 loading benefits from one of two workflows:
For single-stage precision or hunting load production: Throw slightly under target weight with a quality volumetric measure, then trickle to exact weight with a Frankford Arsenal Powder Trickler on a high-resolution scale like the RCBS MatchMaster or Lyman Gen 6 Compact. This approach produces ±0.02 grain consistency regardless of the volumetric variance.
For auto-dispenser loading: The RCBS ChargeMaster Supreme and Hornady Auto-Charge Pro handle long extruded powders effectively. Dispensing time per charge is longer with long-stick grains than short-cut or ball alternatives, but the resulting charge weight accuracy is equivalent.
The long drop tube technique is specifically useful for near-maximum IMR 4831 loads in 300 Winchester Magnum and similar large cases. A 6-10 inch drop tube allows the sticks to settle under gravity in the case before bullet seating, increasing effective packing density by 2-4% and preventing the bullet from compressing an unevenly-settled powder column. Consistent use of the drop tube is more important with IMR 4831 than with short-cut or ball alternatives.
Bullets
IMR 4831 paired with standard-to-heavy, hunting and precision projectiles produces its best results in the medium-large caliber applications where its progressive pressure curve provides consistent acceleration.
| Brand | Model | Weight | Cartridge | Application |
|---|---|---|---|---|
| Nosler | Partition | 115-200 gr | 270 Win / 30-06 / 300 Win Mag | Classic Big Game |
| Nosler | AccuBond | 130-200 gr | 270 Win / 7mm Rem Mag / 300 Win Mag | Bonded Long-Range |
| Nosler | Ballistic Tip | 95-180 gr | 25-06 / 270 Win / 30-06 | Open Country Hunting |
| Sierra | GameKing | 100-180 gr | 270 Win / 30-06 / 243 Win | Traditional Hunting |
| Hornady | InterLock | 100-220 gr | 270 Win / 30-06 | Reliable Hunting |
| Hornady | ELD-X | 130-178 gr | 270 Win / 7mm Rem Mag | Long-Range Hunting |
| Berger | VLD Hunting | 130-190 gr | 270 Win / 7mm Rem Mag | Precision Hunting |
| Barnes | TTSX | 130-168 gr | 270 Win / 30-06 | Lead-Free Hunting |
| Federal | Trophy Bonded | 165-200 gr | 300 Win Mag | Premium Hunting |
| Lapua | Scenar | 136-170 gr | 6.5×55 / 270 Win | Competition Match |
Have you loaded IMR 4831? Your practical data on charge weights, accuracy nodes, temperature behavior, or comparison with H4831SC helps other reloaders more than any spec sheet. Leave a comment below.
Primers
IMR 4831 as a single-base slow-rifle powder ignites adequately from standard large rifle primers in most medium-capacity applications (270 Winchester, 25-06 Remington, standard 30-06 Springfield). For large-capacity magnum applications (7mm Remington Magnum, 300 Winchester Magnum) at maximum charge weights, or in cold conditions below 0°F, magnum large rifle primers provide more reliable complete ignition of the slow powder column.
| Primer | Type | Application |
|---|---|---|
| Federal GM210M | Large Rifle Match | Competition precision – gold standard |
| CCI BR-2 | Large Rifle Benchrest | Competition lowest SD |
| CCI 200 | Large Rifle Standard | 270 Win, 25-06, 30-06 standard loads |
| Federal 210 | Large Rifle Standard | Consistent general use |
| Winchester WLR | Large Rifle Standard | Hunting loads, general use |
| Remington 9-1/2 | Large Rifle Standard | Traditional choice for standard cases |
| CCI 250 | Large Rifle Magnum | 7mm Rem Mag, 300 Win Mag, cold weather |
| Federal 215 | Large Rifle Magnum | Maximum ignition for large magnum cases |
| Winchester WLRM | Large Rifle Magnum | Heavy magnum hunting loads |
| RWS 5341 | Large Rifle | Premium European precision option |
| Fiocchi Large Rifle Magnum | Large Rifle Magnum | Consistent European magnum alternative |
| Ginex Large Rifle | Large Rifle Standard | Cost-effective general option |
Metering and Equipment Compatibility
The long-cut grain geometry is the defining metering limitation of IMR 4831. Standard volumetric powder measures produce ±0.3-0.5 grain charge-to-charge variance – not acceptable for any precision or hunting application without auto-dispenser or hand-weigh correction.
For progressive press hunting ammunition production on a Dillon XL 750 or Hornady Lock-N-Load AP, the Redding Match Grade 3BR with careful attention to consistent handle stroke produces better results than standard powder measures with IMR 4831. Even so, periodic scale verification is recommended given the long-grain metering variability.
For precision reloading at all levels, auto-dispenser or hand-weigh/trickle workflow is the correct approach – the same conclusion as for other long-cut IMR powders.
Reloading Safety Notes
All charge weights must come from current published IMR/Hodgdon load data for IMR 4831 specifically. Do not substitute Hodgdon H4831SC charge weights – H4831SC burns faster and uses different charge weights for the same cartridge. Do not substitute IMR 4350, IMR 4451 Enduron, or Alliant Reloder 22 charge weights without independent verification.
Temperature protocol: loads developed at maximum charge in cool conditions may produce elevated pressure in summer heat. At 0.6-1.0 fps/°F sensitivity, a load at maximum charge validated at 50°F may show pressure signs at 95°F summer temperatures. Validate maximum charges at the highest expected firing temperature.
Starting loads burn dirtier with IMR 4831 than with many modern powders – if you are doing charge development from 10% below maximum, expect more carbon fouling in the first few rounds until reaching the 80%+ pressure level where the powder burns efficiently.
Start 10% below the listed maximum and work up in 0.3-grain increments. Watch for flattened primers, stiff bolt lift, and ejector marks.
See the overpressure in reloading guide for systematic pressure sign identification.
FAQ
Is IMR 4831 the same as Hodgdon H4831SC?
No – they share a name but not a formulation or burn rate. H4831SC burns faster than IMR 4831 and belongs to Hodgdon’s Extreme series with dramatically better temperature stability (~0.3 fps/°F vs IMR 4831’s ~0.6-1.0 fps/°F). Charge weights are not interchangeable. The original DuPont IMR 4831 formula and the Hodgdon H4831 formula were distinct from the beginning – the shared naming convention has always been a source of confusion.
Is IMR 4831 still worth using given modern Enduron alternatives?
For a reloader with established, verified IMR 4831 loads that are performing well in their rifles, the powder remains fully capable. The primary argument for switching to IMR 4451 Enduron is the temperature stability improvement and the decoppering benefit – neither of which requires a switch if the existing loads are working and the shooter can manage the seasonal variation protocol. For new load development starting from scratch, IMR 4451 Enduron or Hodgdon H4831SC offer measurably better seasonal performance at similar or better metering consistency.
Does IMR 4831 work for 300 Win Mag with 220-grain heavy bullets?
At the heavy end of 300 Winchester Magnum bullet weights (200-220 grain ELR projectiles), IMR 4831 is at or beyond the slower end of what the cartridge uses efficiently. Hodgdon H1000 or Alliant Reloder 22 are generally better burn rate matches for 300 Win Mag with very heavy bullets. Verify against published IMR data for specific bullet weights before loading.
Conclusion
IMR 4831 has earned its place in North American reloading history through decades of documented performance in the hunting cartridges that defined post-WWII North American big game hunting. The 270 Winchester, 25-06 Remington, and heavy-bullet 30-06 Springfield applications are where it performs exactly as its reputation describes.
The long-grain metering limitation and the 60-100 fps temperature sensitivity are known trade-offs of a traditional DuPont formulation. Both are manageable with appropriate technique and protocol. For a reloader who values the deepest published data library in its burn rate class and wants a fully proven traditional single-base powder in these applications, IMR 4831 remains a legitimate choice.
Choose IMR 4831 if you load 270 Winchester, 25-06 Remington, 280 Remington, or heavy-bullet 30-06 Springfield with existing verified loads and the temperature protocol is manageable for your application. Choose Hodgdon H4831SC if Extreme series year-round temperature stability is the priority – noting that H4831SC burns faster and has different charge weights. Choose IMR 4451 Enduron if Enduron temperature stability and decoppering are worth starting fresh load development. Choose Alliant Reloder 22 if maximum velocity in 7mm Remington Magnum and 300 Winchester Magnum is the priority and the temperature protocol is acceptable.
Editor’s note: Published load data and manufacturer specifications are the starting point – not the final word. Field experience from reloaders who have actually worked with this powder is the most reliable guide to what it does in practice. If you have used IMR 4831, share your results in the comments.
Editorial note: Originally published 2026, revised May 2026. The revision corrected the source article’s critical error stating that Hodgdon H4831SC is “slower burning” than IMR 4831 – H4831SC burns faster and uses different charge weights. A dedicated section was added to address this dangerous naming confusion directly. Added the temperature stability comparison table with specific inches-at-distance calculations, corrected the density figures to accurate g/cc values rather than g/L as the original presented, added the practical loading workflow section for long-cut grain management, corrected the 300 Win Mag heavy-bullet (200-220 gr) application to note that H1000 is typically better matched, extended the bullet and primer tables with full internal links, and added three community data disclaimer blocks in the correct blockquote format.
