Description
IMR 7977 is an 8-pound jug of slow-burning, extruded rifle powder designed for magnum cartridges like the .300 Win Mag and .338 Lapua. It’s for the handloader who demands consistent velocity and low extreme spread over a long barrel life. We’ve had this on our shelves since fall 2025, and the low return rate tells us folks know what they’re getting.
What Makes It Stand Out
- Extruded kernel design meters consistently through most powder measures, giving you repeatable charges.
- Formulated for heavy bullets in large magnum cases, providing a full, efficient burn in long barrels.
- Our range officer tested it against three competitors; this powder won on reliability, with fewer unburned granules and more consistent point of impact.
- Clean-burning formula helps keep fouling manageable, meaning less time scrubbing and more time shooting.
- Stable across a wide temperature range, so your summer and winter loads stay predictable.
Tech Specs
| Powder Type | Extruded (tubular) |
| Burn Rate | Slow |
| Primary Use | Large Rifle Magnums |
| Net Weight | 8 lb (3.63 kg) |
| Weight (measured) | 2.1 oz (sample kernel) |
| Container | High-density polyethylene jug |
| Manufacturer | IMR / Hodgdon |
| Lot Consistency | High (per our testing) |
Common Questions
What’s the best application for IMR 7977?
It’s built for magnum rifle cartridges pushing heavy bullets. Think .300 Winchester Magnum, .338 Lapua Magnum, 7mm Remington Magnum, and similar cases where you need a slow, progressive burn to maximize velocity without excessive pressure.
How does it meter in a powder thrower?
Very well. The extruded kernels are uniform and cut cleanly. You’ll get consistent throws with minimal trickling needed, especially with a quality rotary-style measure.
Is there load data available?
Yes. Always start with official data from Hodgdon’s website or their annual manual. Never use data for other powders as a substitute. Start low and work up.
✅ Plain, unmarked packaging
✅ Easy 30-day return policy
✅ 256-bit encrypted checkout
✅ USA-based seller
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