IMR Enduron
IMR Enduron 4166
A match-grade medium-speed rifle powder covering mid-capacity cartridges. Hodgdon states it performs comparably to Hodgdon Varget while stressing that charge weights are materially different and data must not be crossed over.
The fast end of the Enduron line and the closest thing IMR has to a Varget analogue in .308 and .22-250, comparable in application but emphatically not in data, since the charge weights are genuinely different. What you are buying is the Enduron package: a copper-fouling-reducer additive that stretches the interval between real bore cleanings, and a temperature-stability claim that holds up in hot-weather load development. The complication is supply. Enduron availability has been unreliable and the line's future in the catalogue is unsettled, so building a competition program around it is a risk.
- .308 Winchester match
- .22-250 varmint
- .257 Roberts
- service rifle .223
Who has IMR Enduron 4166 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) | 0.0741 cc per grain · 0.87 g/cc |
| Composition | single-base |
| Temperature stable | Yes — claimed by the manufacturer |
| Burn-rate position | 118 of 198 (fastest = 1) — what this means |
| Typical cartridges | 308 Winchester, 7.62mm NATO, 22-250 Remington, 257 Roberts |
Grain shape
Extruded single-perforated tube, neutral-burning. Thinnest web in the Enduron family, which is what puts it at the fast end of that ladder: same recipe as its slower siblings, less wall to burn through. It meters like a stick, which is to say indifferently.
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
Fastest of the five Enduron powders; medium rifle speed, essentially alongside IMR 4064.
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 N135 (position 115)
- Accurate 2495 (position 117)
- IMR 4064 (position 119)
- Norma 202 (position 120)
- Accurate 4064 (position 121)
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.