Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 250gr | Barnes Banded Solid RN bullet and 56 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% | 55,796 psi | 87% | 2782 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 54,549 psi | 85% | 2890 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 86% | 57,000 psi | 89% | 2867 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 55,463 psi | 87% | 2887 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 98% | 57,711 psi | 90% | 2917 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 53,983 psi | 85% | 2979 fps | 98.6% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 56,304 psi | 88% | 2940 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 57,406 psi | 90% | 2851 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 56,550 psi | 89% | 2858 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 55,912 psi | 88% | 2881 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 57,537 psi | 90% | 2835 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 53,998 psi | 85% | 2861 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 54,346 psi | 85% | 2874 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 55,390 psi | 87% | 2956 fps | 98.7% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 50,923 psi | 80% | 2881 fps | 97.4% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 55,883 psi | 88% | 2848 fps | 98.7% |
| Bofors RP15 | <<locked>> | 90% | 55,114 psi | 86% | 2871 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 57,551 psi | 90% | 2933 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 55,912 psi | 88% | 2881 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 55,448 psi | 87% | 2884 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 54,534 psi | 85% | 2822 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 88% | 57,319 psi | 90% | 2861 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 57,406 psi | 90% | 2769 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 56,840 psi | 89% | 3002 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,666 psi | 59% | 1788 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 55,840 psi | 88% | 2789 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 56,507 psi | 89% | 2789 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 55,085 psi | 86% | 2799 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 90% | 57,638 psi | 90% | 2927 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 94% | 57,188 psi | 90% | 2799 fps | 95.9% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 51,561 psi | 81% | 2864 fps | 99.9% |
| Lovex S071 | <<locked>> | 94% | 57,450 psi | 90% | 2805 fps | 100% |
| Norma 204 | <<locked>> | 82% | 57,043 psi | 89% | 2848 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 52,678 psi | 83% | 2887 fps | 100% |
| Norma MRP | <<locked>> | 86% | 55,811 psi | 87% | 2897 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 54,752 psi | 86% | 2890 fps | 100% |
| Ramshot Hunter | <<locked>> | 82% | 57,043 psi | 89% | 2844 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 57,246 psi | 90% | 2877 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,725 psi | 61% | 1834 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 53,417 psi | 84% | 2933 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 56,971 psi | 89% | 2963 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 86% | 57,667 psi | 90% | 2838 fps | 100% |
| Rottweil R 905 | <<locked>> | 86% | 56,391 psi | 88% | 2851 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 55,985 psi | 88% | 2848 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 55,390 psi | 87% | 2779 fps | 99.7% |
| Somchem S365 | <<locked>> | 82% | 55,840 psi | 88% | 2782 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 56,724 psi | 89% | 2818 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 56,550 psi | 89% | 2805 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 55,506 psi | 87% | 2831 fps | 97.2% |
| Vihtavuori N555 | <<locked>> | 86% | 56,014 psi | 88% | 2818 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 55,303 psi | 87% | 2900 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 92% | 56,173 psi | 88% | 2894 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 96% | 57,464 psi | 90% | 2963 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 96% | 54,795 psi | 86% | 2966 fps | 98.3% |
| Winchester StaBALL HD | <<locked>> | 90% | 57,580 psi | 90% | 2930 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 56,434 psi | 88% | 2815 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% | 42,714 psi | 67% | 2579 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 44,251 psi | 69% | 2707 fps | 97.9% |
| ADI AR 2209 | <<locked>> | 80% | 46,702 psi | 73% | 2703 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 80% | 42,018 psi | 66% | 2651 fps | 98.3% |
| ADI AR 2217 | <<locked>> | 82% | 33,562 psi | 53% | 2461 fps | 96.1% |
| ADI AR 2218 | <<locked>> | 94% | 43,424 psi | 68% | 2766 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 28,689 psi | 45% | 2372 fps | 97% |
| Alliant Reloder-16 | <<locked>> | 80% | 53,795 psi | 84% | 2802 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,659 psi | 73% | 2697 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,743 psi | 67% | 2657 fps | 99.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 41,539 psi | 65% | 2595 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,839 psi | 56% | 2539 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 46,760 psi | 73% | 2759 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 41,147 psi | 64% | 2697 fps | 95.2% |
| Alliant Reloder-50 | <<locked>> | 96% | 43,903 psi | 69% | 2746 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 40,770 psi | 64% | 2569 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 39,726 psi | 62% | 2595 fps | 98.7% |
| Bofors RP30 | <<locked>> | 80% | 33,402 psi | 52% | 2477 fps | 96.2% |
| Bofors RP5 | <<locked>> | 80% | 42,743 psi | 67% | 2657 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 80% | 34,026 psi | 53% | 2474 fps | 96.9% |
| Hodgdon H4831 | <<locked>> | 80% | 44,614 psi | 70% | 2651 fps | 98.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 43,801 psi | 69% | 2635 fps | 98.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 50,531 psi | 79% | 2677 fps | 100% |
| Hodgdon Retumbo | 90.3 gr | 80% | 35,027 psi | 55% | 2582 fps | 98.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,355 psi | 44% | 1601 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 52,330 psi | 82% | 2736 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 52,910 psi | 83% | 2740 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,614 psi | 71% | 2638 fps | 98.6% |
| IMR 7828 SSC | <<locked>> | 80% | 40,741 psi | 64% | 2635 fps | 98.1% |
| IMR 7977 Enduron | <<locked>> | 92% | 53,679 psi | 84% | 2743 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 86% | 32,053 psi | 50% | 2464 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 36,840 psi | 58% | 2461 fps | 99.6% |
| Norma 204 | <<locked>> | 80% | 53,171 psi | 83% | 2792 fps | 100% |
| Norma 217 | <<locked>> | 82% | 28,224 psi | 44% | 2375 fps | 96.1% |
| Norma MRP | <<locked>> | 80% | 45,266 psi | 71% | 2723 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 40,683 psi | 64% | 2644 fps | 98.5% |
| Ramshot Hunter | <<locked>> | 80% | 53,258 psi | 83% | 2789 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 36,622 psi | 57% | 2530 fps | 98.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,008 psi | 45% | 1637 fps | 100% |
| ReloadSwiss RS 76 | 96.6 gr | 80% | 34,127 psi | 53% | 2556 fps | 99.1% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 36,201 psi | 57% | 2579 fps | 95.7% |
| Rottweil R 904 | <<locked>> | 80% | 47,514 psi | 74% | 2677 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 80% | 46,238 psi | 72% | 2687 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 45,905 psi | 72% | 2684 fps | 99.7% |
| Somchem S361 | <<locked>> | 80% | 48,530 psi | 76% | 2667 fps | 99% |
| Somchem S365 | <<locked>> | 80% | 52,156 psi | 82% | 2733 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,702 psi | 73% | 2661 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 80% | 40,770 psi | 64% | 2546 fps | 99.3% |
| Vihtavuori N170 | <<locked>> | 90% | 48,530 psi | 76% | 2713 fps | 95.6% |
| Vihtavuori N555 | <<locked>> | 80% | 46,166 psi | 72% | 2671 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 44,976 psi | 70% | 2720 fps | 98.6% |
| Vihtavuori N565 | <<locked>> | 80% | 37,449 psi | 59% | 2549 fps | 96.9% |
| Vihtavuori N568 | <<locked>> | 84% | 37,521 psi | 59% | 2595 fps | 95.6% |
| Vihtavuori N570 | 105.4 gr | 90% | 44,077 psi | 69% | 2769 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 80% | 39,450 psi | 62% | 2654 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 43,018 psi | 67% | 2598 fps | 99.3% |
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 63 powders for .338-378 Weath. Mag. loaded with the .338 | 250gr | Barnes Banded Solid RN. Hodgdon Retumbo delivers the highest muzzle velocity at 3,002 fps; across all powders the maximum-charge window runs from 1,788 fps to 3,002 fps. Accurate 8700 gives the best case fill at 100 %, and 63 of the 63 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 250.0 gr projectile in 0.338" calls for a 1:13.5 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2218, ADI AR 2225 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 | 250gr | Barnes Banded Solid RN they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 8700, Hodgdon US 869, Lovex D100 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.