Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 265gr | Nosler AccuBond Long Range bullet and 57 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N570, Hodgdon Retumbo and ReloadSwiss RS 76.
Important Notice: DO NOT go below Minimum Charge or above Maximum Charge. Since we have no control over the equipment and components used, any responsibility and liability for the results achieved is rejected.
Only powders/loads that match the current filter criteria are displayed: max pressure of a load ≤ 90% of max. standardized pressure, fill rate ≥ 80% and propellant combustion ≥ 95%. Use the sliders above the tables to adjust these thresholds.
Charge: Powder weight in grains. Start with the minimum load and work up carefully.
FR (Fill Rate): Case fill as a percentage. Values above 100% mean compressed loads.
MaxP / %: Maximum chamber pressure in bar and as a percentage of the standardized maximum for this caliber.
V(0): Muzzle velocity in feet per second (fps) at the standardized barrel length.
z (Powder Burn): Estimated propellant combustion percentage at bullet exit.
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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 88% | 55,912 psi | 88% | 2703 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 54,781 psi | 86% | 2815 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 86% | 57,334 psi | 90% | 2792 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 55,477 psi | 87% | 2805 fps | 100% |
| ADI AR 2217 | <<locked>> | 96% | 53,983 psi | 85% | 2785 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 54,041 psi | 85% | 2904 fps | 99% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 56,304 psi | 88% | 2858 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 57,493 psi | 90% | 2789 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 57,522 psi | 90% | 2766 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 56,869 psi | 89% | 2779 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 55,927 psi | 88% | 2802 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 54,128 psi | 85% | 2710 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 54,215 psi | 85% | 2782 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 54,549 psi | 85% | 2795 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 55,651 psi | 87% | 2884 fps | 99% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 50,879 psi | 80% | 2805 fps | 97.8% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 55,999 psi | 88% | 2772 fps | 99% |
| Bofors RP15 | <<locked>> | 90% | 55,288 psi | 87% | 2792 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 57,595 psi | 90% | 2854 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 55,927 psi | 88% | 2802 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 55,564 psi | 87% | 2805 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 54,810 psi | 86% | 2743 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 88% | 57,377 psi | 90% | 2779 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 57,566 psi | 90% | 2690 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 56,971 psi | 89% | 2920 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,681 psi | 59% | 1726 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 56,014 psi | 88% | 2710 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 56,724 psi | 89% | 2710 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 55,347 psi | 87% | 2723 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 88% | 53,925 psi | 85% | 2792 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 94% | 57,319 psi | 90% | 2723 fps | 96.3% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 51,721 psi | 81% | 2789 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 57,667 psi | 90% | 2726 fps | 100% |
| Norma 204 | <<locked>> | 82% | 57,116 psi | 90% | 2769 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 52,692 psi | 83% | 2808 fps | 100% |
| Norma MRP | <<locked>> | 86% | 56,101 psi | 88% | 2818 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 54,998 psi | 86% | 2812 fps | 100% |
| Ramshot Hunter | <<locked>> | 82% | 57,101 psi | 89% | 2759 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 57,363 psi | 90% | 2799 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,653 psi | 61% | 1765 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 53,621 psi | 84% | 2854 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 57,029 psi | 89% | 2887 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 86% | 57,725 psi | 90% | 2759 fps | 100% |
| Rottweil R 905 | <<locked>> | 86% | 56,478 psi | 89% | 2769 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 56,086 psi | 88% | 2766 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 55,463 psi | 87% | 2700 fps | 99.8% |
| Somchem S365 | <<locked>> | 82% | 56,057 psi | 88% | 2700 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 56,956 psi | 89% | 2740 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 56,782 psi | 89% | 2730 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 55,680 psi | 87% | 2759 fps | 97.6% |
| Vihtavuori N555 | <<locked>> | 86% | 56,057 psi | 88% | 2733 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 55,550 psi | 87% | 2822 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 92% | 56,231 psi | 88% | 2815 fps | 100% |
| Vihtavuori N568 | <<locked>> | 96% | 57,609 psi | 90% | 2887 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 96% | 54,723 psi | 86% | 2887 fps | 98.6% |
| Winchester StaBALL HD | <<locked>> | 88% | 53,751 psi | 84% | 2799 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 56,724 psi | 89% | 2743 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 42,946 psi | 67% | 2510 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 44,367 psi | 70% | 2638 fps | 98.3% |
| ADI AR 2209 | <<locked>> | 80% | 46,905 psi | 74% | 2631 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 42,134 psi | 66% | 2582 fps | 98.7% |
| ADI AR 2217 | <<locked>> | 80% | 31,444 psi | 49% | 2343 fps | 95.7% |
| ADI AR 2218 | <<locked>> | 92% | 40,553 psi | 64% | 2635 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 28,877 psi | 45% | 2320 fps | 97.7% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 47,297 psi | 74% | 2631 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 53,911 psi | 84% | 2717 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,847 psi | 73% | 2625 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,859 psi | 67% | 2585 fps | 99.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 41,684 psi | 65% | 2523 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 36,013 psi | 56% | 2474 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 47,094 psi | 74% | 2687 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 41,263 psi | 65% | 2631 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 94% | 40,727 psi | 64% | 2618 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 40,915 psi | 64% | 2503 fps | 95.7% |
| Bofors RP15 | <<locked>> | 80% | 39,900 psi | 63% | 2526 fps | 99% |
| Bofors RP30 | <<locked>> | 80% | 33,605 psi | 53% | 2418 fps | 96.9% |
| Bofors RP5 | <<locked>> | 80% | 42,859 psi | 67% | 2585 fps | 99.5% |
| Hodgdon H1000 | <<locked>> | 80% | 34,127 psi | 53% | 2411 fps | 97.5% |
| Hodgdon H4831 | <<locked>> | 80% | 44,759 psi | 70% | 2579 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 43,947 psi | 69% | 2562 fps | 98.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 50,778 psi | 80% | 2598 fps | 100% |
| Hodgdon Retumbo | 86.8 gr | 80% | 35,259 psi | 55% | 2523 fps | 99% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,384 psi | 44% | 1542 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 52,533 psi | 82% | 2661 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 53,127 psi | 83% | 2661 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,788 psi | 72% | 2566 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 80% | 40,988 psi | 64% | 2569 fps | 98.6% |
| IMR 7977 Enduron | <<locked>> | 92% | 53,693 psi | 84% | 2671 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 84% | 30,139 psi | 47% | 2349 fps | 95.2% |
| Lovex S071 | <<locked>> | 80% | 37,072 psi | 58% | 2398 fps | 99.8% |
| Norma 204 | <<locked>> | 80% | 53,447 psi | 84% | 2713 fps | 100% |
| Norma 217 | <<locked>> | 80% | 26,527 psi | 42% | 2264 fps | 95.7% |
| Norma MRP | <<locked>> | 80% | 45,455 psi | 71% | 2651 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 40,944 psi | 64% | 2579 fps | 98.9% |
| Ramshot Hunter | <<locked>> | 80% | 53,505 psi | 84% | 2710 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 36,811 psi | 58% | 2464 fps | 99.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,051 psi | 46% | 1578 fps | 100% |
| ReloadSwiss RS 76 | 92.8 gr | 80% | 34,301 psi | 54% | 2497 fps | 99.5% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 33,649 psi | 53% | 2451 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 47,790 psi | 75% | 2605 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 80% | 46,441 psi | 73% | 2615 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 46,093 psi | 72% | 2612 fps | 99.8% |
| Somchem S361 | <<locked>> | 80% | 48,588 psi | 76% | 2595 fps | 99.2% |
| Somchem S365 | <<locked>> | 80% | 52,388 psi | 82% | 2654 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,847 psi | 73% | 2589 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 40,959 psi | 64% | 2477 fps | 99.5% |
| Vihtavuori N170 | <<locked>> | 88% | 45,527 psi | 71% | 2589 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 80% | 46,311 psi | 73% | 2595 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 45,165 psi | 71% | 2651 fps | 98.9% |
| Vihtavuori N565 | <<locked>> | 80% | 37,536 psi | 59% | 2484 fps | 97.4% |
| Vihtavuori N568 | <<locked>> | 82% | 35,099 psi | 55% | 2474 fps | 95.2% |
| Vihtavuori N570 | 99 gr | 88% | 41,162 psi | 65% | 2641 fps | 95.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 39,755 psi | 62% | 2585 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 43,207 psi | 68% | 2530 fps | 99.5% |
Recommended = one of the top powders for this cartridge and bullet combination.
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 57 powders for .338-378 Weath. Mag. loaded with the .338 | 265gr | Nosler AccuBond Long Range. Hodgdon Retumbo delivers the highest muzzle velocity at 2,920 fps; across all powders the maximum-charge window runs from 1,726 fps to 2,920 fps. ADI AR 2218 gives the best case fill at 100 %, and 57 of the 57 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 265.0 gr projectile in 0.338" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, Alliant Reloder-50 reach 100 % fill or more at maximum charge, so these are compressed loads: they need a long drop tube to seat cleanly and react sensitively to the case capacity of your own brass lot. Vihtavuori N570, Hodgdon Retumbo, ReloadSwiss RS 76 rank at the top here: for .338-378 Weath. Mag. with the .338 | 265gr | Nosler AccuBond Long Range they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.