IMR Enduron
IMR Enduron 7977
A true magnum propellant. Hodgdon emphasises that its loading density fills large magnum cases well at maximum charges, which it links to uniformity and accuracy. Stated to perform comparably to Hodgdon H1000, with materially different charge weights.
Specifications
| Manufacturer | IMR |
|---|---|
| Product family | IMR Enduron |
| Status | Currently produced |
| Application | rifle |
| Grain form | extruded |
| Composition | single-base |
| Temperature stable | Yes — claimed by the manufacturer |
| Burn-rate position | 180 of 198 (fastest = 1) — what this means |
| Typical cartridges | 300 Winchester Magnum, 7mm Remington Magnum, 338 Lapua Magnum |
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
Very slow magnum rifle speed, slower than IMR 7828 SSC and near Hodgdon H1000.
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:
- Vihtavuori N565 (position 177)
- Vihtavuori N170 (position 178)
- Accurate MAGPRO (position 179)
- Alliant Reloder 26 (position 181)
- Hodgdon H1000 (position 182)
- Ramshot Grand (position 183)
Sources
Other IMR powders
Verify the charge, not just the recipe
Good data gets you a safe starting point. It does not tell you what actually went into the case on stroke 340 — a bridged measure, a double charge, a squib. That is what an RCM Laser Powder Check is for.