Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 225gr | Woodleigh PP SN bullet and 61 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Accurate MAGPRO and Vihtavuori N570.
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% | 54,186 psi | 85% | 2843 fps | 100% |
| Accurate MAGPRO | <<locked>> | 90% | 57,638 psi | 90% | 3071 fps | 99.1% |
| ADI AR 2209 | <<locked>> | 86% | 55,521 psi | 87% | 2926 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 90% | 57,566 psi | 90% | 2996 fps | 99.6% |
| ADI AR 2217 | <<locked>> | 98% | 55,941 psi | 88% | 2967 fps | 99.7% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 52,982 psi | 83% | 2997 fps | 96.5% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,694 psi | 86% | 2988 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 55,680 psi | 87% | 2916 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 55,071 psi | 86% | 2915 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 88% | 54,172 psi | 85% | 2931 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 90% | 55,956 psi | 88% | 2902 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 55,985 psi | 88% | 2969 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 56,463 psi | 88% | 2984 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 54,230 psi | 85% | 2986 fps | 96.9% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 54,534 psi | 85% | 2894 fps | 97.2% |
| Bofors RP15 | <<locked>> | 92% | 57,087 psi | 89% | 3041 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 55,709 psi | 87% | 2978 fps | 99.7% |
| Bofors RP5 | <<locked>> | 88% | 54,172 psi | 85% | 2995 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 57,551 psi | 90% | 3054 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 56,724 psi | 89% | 2969 fps | 100% |
| Hodgdon H4831 | <<locked>> | 92% | 56,666 psi | 89% | 2926 fps | 99.1% |
| Hodgdon H4831 SC | <<locked>> | 88% | 55,695 psi | 87% | 2911 fps | 99% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 55,927 psi | 88% | 2841 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 54,955 psi | 86% | 3120 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,580 psi | 60% | 1865 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 54,404 psi | 85% | 2910 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 56,463 psi | 88% | 2877 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 57,232 psi | 90% | 2969 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 88% | 55,840 psi | 88% | 2977 fps | 99.5% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 51,242 psi | 80% | 2899 fps | 99% |
| Lovex S070 | <<locked>> | 82% | 56,608 psi | 89% | 2880 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 55,898 psi | 88% | 2867 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,492 psi | 87% | 2906 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 52,011 psi | 82% | 2922 fps | 100% |
| Norma MRP | <<locked>> | 86% | 54,244 psi | 85% | 2950 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,492 psi | 89% | 2896 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 55,912 psi | 88% | 2982 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 82% | 55,477 psi | 87% | 2905 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 57,261 psi | 90% | 2955 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,682 psi | 62% | 1910 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 57,145 psi | 90% | 2965 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 55,680 psi | 87% | 3038 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 55,042 psi | 86% | 2998 fps | 98.9% |
| Rottweil R 904 | <<locked>> | 86% | 56,159 psi | 88% | 2895 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 86% | 54,868 psi | 86% | 2908 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 82% | 56,608 psi | 89% | 2940 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,029 psi | 89% | 2834 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 54,476 psi | 85% | 2966 fps | 99.9% |
| Somchem S361 | <<locked>> | 86% | 57,740 psi | 90% | 2888 fps | 99.2% |
| Somchem S365 | <<locked>> | 82% | 54,114 psi | 85% | 2849 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,158 psi | 86% | 2878 fps | 100% |
| Vihtavuori N150 | <<locked>> | 82% | 55,608 psi | 87% | 2785 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 56,826 psi | 89% | 2889 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 54,346 psi | 85% | 2877 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 54,621 psi | 86% | 2964 fps | 99% |
| Vihtavuori N565 | <<locked>> | 92% | 54,534 psi | 85% | 2938 fps | 99.1% |
| Vihtavuori N568 | <<locked>> | 96% | 55,753 psi | 87% | 3003 fps | 98.6% |
| Vihtavuori N570 | <<locked>> | 96% | 53,388 psi | 84% | 2994 fps | 96.4% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 57,551 psi | 90% | 2837 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 55,463 psi | 87% | 2985 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 56,318 psi | 88% | 2893 fps | 99.9% |
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% | 41,437 psi | 65% | 2622 fps | 99.5% |
| Accurate MAGPRO | 100.2 gr | 80% | 40,509 psi | 63% | 2749 fps | 95.2% |
| ADI AR 2209 | <<locked>> | 80% | 45,411 psi | 71% | 2749 fps | 98.6% |
| ADI AR 2213 | <<locked>> | 80% | 40,698 psi | 64% | 2684 fps | 96.4% |
| ADI AR 2217 | <<locked>> | 86% | 37,072 psi | 58% | 2598 fps | 95.4% |
| ADI AR 2218 | <<locked>> | 98% | 48,646 psi | 76% | 2922 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 82% | 29,689 psi | 47% | 2439 fps | 95.1% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,156 psi | 82% | 2863 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,368 psi | 71% | 2743 fps | 98.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,365 psi | 65% | 2691 fps | 97.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,089 psi | 63% | 2639 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,664 psi | 54% | 2567 fps | 98.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,107 psi | 71% | 2800 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 49,690 psi | 78% | 2914 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 48,153 psi | 75% | 2779 fps | 95.7% |
| Bofors RP15 | <<locked>> | 80% | 38,435 psi | 60% | 2690 fps | 97.6% |
| Bofors RP30 | <<locked>> | 84% | 36,985 psi | 58% | 2613 fps | 95.6% |
| Bofors RP5 | <<locked>> | 80% | 41,365 psi | 65% | 2759 fps | 98.5% |
| Hodgdon H1000 | <<locked>> | 82% | 33,315 psi | 52% | 2569 fps | 95.4% |
| Hodgdon H4350 | <<locked>> | 80% | 53,287 psi | 84% | 2913 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 82% | 40,828 psi | 64% | 2635 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,511 psi | 67% | 2670 fps | 96.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,052 psi | 77% | 2741 fps | 100% |
| Hodgdon Retumbo | 94.8 gr | 80% | 33,837 psi | 53% | 2667 fps | 97% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,239 psi | 44% | 1670 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,126 psi | 80% | 2854 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 46,862 psi | 73% | 2726 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,512 psi | 70% | 2746 fps | 97.7% |
| IMR 7828 SSC | <<locked>> | 80% | 41,945 psi | 66% | 2721 fps | 96.8% |
| IMR 8133 Enduron | <<locked>> | 92% | 37,956 psi | 59% | 2656 fps | 95.8% |
| Lovex S070 | <<locked>> | 80% | 53,040 psi | 83% | 2826 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,737 psi | 56% | 2497 fps | 98.4% |
| Norma 204 | <<locked>> | 80% | 51,779 psi | 81% | 2845 fps | 99.4% |
| Norma 217 | <<locked>> | 86% | 31,067 psi | 49% | 2496 fps | 95.1% |
| Norma MRP | <<locked>> | 80% | 43,830 psi | 69% | 2764 fps | 99.3% |
| Norma URP | <<locked>> | 80% | 52,852 psi | 83% | 2841 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 44,164 psi | 69% | 2777 fps | 97.8% |
| Ramshot Hunter | <<locked>> | 80% | 51,793 psi | 81% | 2846 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,885 psi | 61% | 2633 fps | 98% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,950 psi | 45% | 1709 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,171 psi | 83% | 2906 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 32,924 psi | 52% | 2564 fps | 96.8% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 40,582 psi | 64% | 2723 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 46,253 psi | 72% | 2724 fps | 97.9% |
| Rottweil R 905 | <<locked>> | 80% | 44,947 psi | 70% | 2731 fps | 98.7% |
| Shooters World SW4350 | <<locked>> | 80% | 53,040 psi | 83% | 2884 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,534 psi | 84% | 2782 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,599 psi | 70% | 2792 fps | 99.1% |
| Somchem S361 | <<locked>> | 80% | 47,224 psi | 74% | 2714 fps | 97.5% |
| Somchem S365 | <<locked>> | 80% | 50,676 psi | 79% | 2798 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,353 psi | 71% | 2709 fps | 99.2% |
| Vihtavuori N150 | <<locked>> | 80% | 52,199 psi | 82% | 2736 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,348 psi | 60% | 2558 fps | 97.5% |
| Vihtavuori N555 | <<locked>> | 80% | 44,570 psi | 70% | 2718 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 41,452 psi | 65% | 2710 fps | 96% |
| Vihtavuori N565 | <<locked>> | 82% | 38,783 psi | 61% | 2632 fps | 95.4% |
| Vihtavuori N568 | <<locked>> | 88% | 41,843 psi | 66% | 2741 fps | 95% |
| Vihtavuori N570 | 116.8 gr | 94% | 49,603 psi | 78% | 2925 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,664 psi | 84% | 2784 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,695 psi | 59% | 2686 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,440 psi | 71% | 2710 fps | 98.7% |
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 61 powders for .338-378 Weath. Mag. loaded with the .338 | 225gr | Woodleigh PP SN. Hodgdon Retumbo delivers the highest muzzle velocity at 3,120 fps; across all powders the maximum-charge window runs from 1,865 fps to 3,120 fps. ADI AR 2218 gives the best case fill at 100 %, and 61 of the 61 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 60–90 %, leaving at least 10 % headroom. The 225.0 gr projectile in 0.338" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, Hodgdon TrailBoss 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. Hodgdon Retumbo, Accurate MAGPRO, Vihtavuori N570 rank at the top here: for .338-378 Weath. Mag. with the .338 | 225gr | Woodleigh PP SN 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.