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.
A true magnum powder, and the Enduron that fills a big case properly: .300 Winchester Magnum, 7mm Remington Magnum, .338 Lapua, right up near maximum where loading density does its own work for uniformity. The temperature-stability claim earns its money here, because this is exactly the class of load where a hot day and a full case can bite. Comparable to H1000 in role, not in charge weight. Enduron supply across the line is currently uncertain.
- .338 Lapua Magnum
- .300 Winchester Magnum
- 7mm Remington Magnum
- long-range magnum match
Who has IMR Enduron 7977 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) | 0.0707 cc per grain · 0.92 g/cc |
| 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 |
Grain shape
Neutral-burning extruded tube with a heavy web; a lot of wall to burn through is precisely why it is slow enough for magnum cases. Long kernels plus a large charge volume mean the drop tube matters, so weigh charges and drop them through a long tube for consistent packing.
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
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
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.