IMR Enduron
IMR Enduron 8133
Intended for the largest overbore magnum cases, where a very slow powder is needed to fill the case and deliver uniform pressures. Hodgdon states it performs comparably to Hodgdon Retumbo with materially different charge weights.
The slowest Enduron and a specialist: overbore magnums such as 6.5-300 Weatherby, .264 Winchester Magnum, 28 Nosler and .300 Remington Ultra Magnum, where anything faster spikes before it fills the case. In an ordinary cartridge it is useless; in a barrel-burner it is one of the few powders that makes the case behave. Retumbo territory in role, with the Enduron decoppering and temperature package on top, and the same uncertain supply as the rest of the line.
- 6.5-300 Weatherby Magnum
- 28 Nosler
- .300 Remington Ultra Magnum
- .264 Winchester Magnum
Who has IMR Enduron 8133 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) | 0.0714 cc per grain · 0.91 g/cc |
| Composition | single-base |
| Temperature stable | Yes — claimed by the manufacturer |
| Burn-rate position | 188 of 198 (fastest = 1) — what this means |
| Typical cartridges | 6.5-300 Weatherby Magnum, 264 Winchester Magnum, 28 Nosler, 300 Remington Ultra Magnum |
Grain shape
Extruded tube with the thickest web in the Enduron ladder: same family, most wall, slowest burn. Large long kernels mean poor metering and tight case fill, so weigh charges and use a long drop tube.
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
The slowest powder in the Enduron family; in the overrun-magnum range near Hodgdon Retumbo.
Chart agreement: consistent, but single-publisher - ranked only by Hodgdon (and echoed by the Wolfe/LoadData compilation). No second manufacturer's chart carries it, so the position is uncorroborated. Ranked by: Hodgdon, Wolfe/LoadData.
Powders charted near it — neighbours on the chart are not substitutes, and adjacency tells you nothing about what charge either one takes:
- Norma 217 (position 185)
- Hodgdon Retumbo (position 186)
- Winchester StaBALL HD (position 187)
- Vihtavuori N568 (position 189)
- Ramshot LRT (position 190)
- Vihtavuori N570 (position 191)
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.