IMR Enduron
IMR Enduron 4955
A slower match-grade Enduron powder aimed at big-game cartridges with heavier bullets. Hodgdon states it performs comparably to Hodgdon H4831 with materially different charge weights.
The slow Enduron, sitting near H4831 in role: heavy bullets in .25-06, .270 Winchester, .280 Remington and .300 Winchester Magnum. Same package as the rest of the line, with the decoppering additive, the temperature-stability claim, and a loading density chosen to fill the cases it targets. It has always been the least-discussed powder in the family, and like the rest of it, supply is currently uncertain.
- heavy-bullet .270 Winchester
- .280 Remington
- .25-06 Remington
- .300 Winchester Magnum
Who has IMR Enduron 4955 today
Checked October 10Out of stock at every store we track
| Store | Size | Shelf | In hand /lb | Stock |
|---|---|---|---|---|
| Hodgdon (direct)Terms not published | 8 lb | $453.99 | $60.68 est. | Out |
| Hodgdon (direct)Terms not published | 1 lb | $66.99 | $98.43 est. | Out |
“In hand” is the shelf price plus that store’s hazmat fee and shipping, spread over one container. Stock is checked once a day — confirm on the store’s page before ordering. Compare all powders →
Specifications
| Manufacturer | IMR |
|---|---|
| Product family | IMR Enduron |
| Status | Currently produced |
| Application | rifle |
| Grain form | extruded |
| Lee VMD (bulk density) | 0.0724 cc per grain · 0.90 g/cc |
| Composition | single-base |
| Temperature stable | Yes — claimed by the manufacturer |
| Burn-rate position | 168 of 198 (fastest = 1) — what this means |
| Typical cartridges | 25-06 Remington, 270 Winchester, 280 Remington, 300 Winchester Magnum |
Grain shape
Extruded single-perforated tube; thicker web again than IMR Enduron 4451, which is the whole mechanism behind its slower burn. Long kernels meter poorly through a volumetric measure.
Why geometry decides burn rate more than chemistry does: Shape Is the Product.
Enduron powders are marketed on four shared claims: a copper fouling eliminator additive, reduced sensitivity to temperature change, loading density matched to the intended cartridge class, and a REACH-compliant formulation. Extruded single-base, made in Canada.
Burn rate
Slow; between IMR Enduron 4451 and IMR Enduron 7977, and near Hodgdon H4831.
Chart agreement: consistent across the three charts that list it Ranked by: Hodgdon, Vihtavuori, Wolfe/LoadData.
Powders charted near it — neighbours on the chart are not substitutes, and adjacency tells you nothing about what charge either one takes:
- Hodgdon H4831 (position 166)
- Hodgdon H4831SC (position 166)
- Vihtavuori N560 (position 167)
- Norma MRP (position 169)
- Alliant Reloder 22 (position 170)
- Norma MRP-2 (position 171)
Sources
The specifications above come from IMR's own published documentation, linked below. The two “RCM's read” sections are ours, not theirs — our assessment of what this powder is like to load, drawn from its published characteristics and from what handloaders consistently report. No manufacturer endorses them and no source below backs them. If you think we have one wrong, tell us — we would rather fix it.