Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 210gr | Impala RNFP KO bullet and 63 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ReloadSwiss RS 76 and ReloadSwiss RS 80.
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% | 54,578 psi | 86% | 2976 fps | 100% |
| Accurate High Country | <<locked>> | 86% | 55,376 psi | 87% | 3123 fps | 99.4% |
| Accurate MAGPRO | <<locked>> | 88% | 56,173 psi | 88% | 3127 fps | 98.7% |
| ADI AR 2209 | <<locked>> | 86% | 54,897 psi | 86% | 3054 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 90% | 56,637 psi | 89% | 3123 fps | 99.5% |
| ADI AR 2217 | <<locked>> | 98% | 54,940 psi | 86% | 3087 fps | 99.5% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 53,505 psi | 84% | 3117 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 55,216 psi | 87% | 3051 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 82% | 55,027 psi | 86% | 3048 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 54,636 psi | 86% | 3041 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 90% | 57,348 psi | 90% | 3123 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 90% | 55,434 psi | 87% | 3035 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 55,042 psi | 86% | 3100 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 55,999 psi | 88% | 3127 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 56,681 psi | 89% | 3182 fps | 97.5% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 57,232 psi | 90% | 3068 fps | 97.6% |
| Bofors RP15 | <<locked>> | 92% | 56,608 psi | 89% | 3107 fps | 99.9% |
| Bofors RP30 | <<locked>> | 96% | 55,201 psi | 87% | 3114 fps | 99.6% |
| Bofors RP5 | <<locked>> | 90% | 57,348 psi | 90% | 3123 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 96% | 56,434 psi | 88% | 3110 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 88% | 56,188 psi | 88% | 3051 fps | 99% |
| Hodgdon H4831 SC | <<locked>> | 88% | 55,129 psi | 86% | 3035 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 55,564 psi | 87% | 2969 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 57,609 psi | 90% | 3241 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,768 psi | 59% | 1949 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 57,319 psi | 90% | 3028 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 54,911 psi | 86% | 2986 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 56,782 psi | 89% | 3031 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 90% | 54,955 psi | 86% | 3100 fps | 99.3% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,472 psi | 78% | 3035 fps | 98.9% |
| Lovex S070 | <<locked>> | 82% | 56,536 psi | 89% | 3012 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,086 psi | 88% | 2999 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,042 psi | 86% | 3031 fps | 99.7% |
| Norma 217ᴾ | <<locked>> | 100% | 50,111 psi | 79% | 3061 fps | 99.9% |
| Norma MRP | <<locked>> | 88% | 57,363 psi | 90% | 3140 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,159 psi | 88% | 3028 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 55,825 psi | 87% | 3123 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 82% | 55,100 psi | 86% | 3035 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 54,592 psi | 86% | 3054 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,682 psi | 61% | 1995 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 56,405 psi | 88% | 3097 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 54,505 psi | 85% | 3169 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 54,259 psi | 85% | 3130 fps | 98.7% |
| Rottweil R 904 | <<locked>> | 86% | 55,709 psi | 87% | 3018 fps | 99.3% |
| Rottweil R 905 | <<locked>> | 86% | 54,433 psi | 85% | 3035 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 82% | 56,536 psi | 89% | 3012 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,116 psi | 90% | 2959 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 57,522 psi | 90% | 3087 fps | 99.9% |
| Somchem S361 | <<locked>> | 86% | 57,290 psi | 90% | 3009 fps | 99.1% |
| Somchem S365 | <<locked>> | 84% | 57,435 psi | 90% | 3031 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,216 psi | 87% | 3009 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 57,696 psi | 90% | 3015 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 54,650 psi | 86% | 2986 fps | 99.9% |
| Vihtavuori N170 | <<locked>> | 96% | 57,450 psi | 90% | 3054 fps | 95.8% |
| Vihtavuori N550 | <<locked>> | 82% | 57,058 psi | 89% | 3022 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 54,389 psi | 85% | 3015 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 56,768 psi | 89% | 3136 fps | 99.2% |
| Vihtavuori N565 | <<locked>> | 92% | 54,244 psi | 85% | 3071 fps | 99.1% |
| Vihtavuori N568 | <<locked>> | 96% | 54,868 psi | 86% | 3130 fps | 98.4% |
| Vihtavuori N570 | <<locked>> | 98% | 55,724 psi | 87% | 3189 fps | 96.9% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 56,942 psi | 89% | 2959 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 54,418 psi | 85% | 3127 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 54,520 psi | 85% | 2995 fps | 99.7% |
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% | 42,525 psi | 67% | 2766 fps | 99.6% |
| Accurate High Country | <<locked>> | 80% | 45,426 psi | 71% | 2940 fps | 97.8% |
| Accurate MAGPRO | <<locked>> | 80% | 43,004 psi | 67% | 2877 fps | 95.9% |
| ADI AR 2209 | <<locked>> | 80% | 45,179 psi | 71% | 2874 fps | 98.5% |
| ADI AR 2213 | <<locked>> | 80% | 40,857 psi | 64% | 2815 fps | 96.3% |
| ADI AR 2217 | <<locked>> | 86% | 37,521 psi | 59% | 2730 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 82% | 30,603 psi | 48% | 2589 fps | 95.8% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 45,818 psi | 72% | 2881 fps | 98.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 51,590 psi | 81% | 2995 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,411 psi | 71% | 2874 fps | 98.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,655 psi | 65% | 2831 fps | 97.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,393 psi | 63% | 2779 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,157 psi | 55% | 2710 fps | 99% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,194 psi | 71% | 2946 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 49,153 psi | 77% | 3048 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 47,819 psi | 75% | 2897 fps | 95.4% |
| Bofors RP15 | <<locked>> | 80% | 38,841 psi | 61% | 2762 fps | 97% |
| Bofors RP30 | <<locked>> | 82% | 35,186 psi | 55% | 2700 fps | 95% |
| Bofors RP5 | <<locked>> | 80% | 41,655 psi | 65% | 2831 fps | 97.9% |
| Hodgdon H1000 | <<locked>> | 82% | 35,795 psi | 56% | 2690 fps | 95.5% |
| Hodgdon H4831 | <<locked>> | 80% | 43,366 psi | 68% | 2815 fps | 96.4% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,641 psi | 67% | 2799 fps | 96.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,052 psi | 77% | 2871 fps | 100% |
| Hodgdon Retumbo | 93.1 gr | 80% | 34,476 psi | 54% | 2743 fps | 96.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,427 psi | 45% | 1745 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,778 psi | 80% | 2920 fps | 99.8% |
| IMR 4831 | <<locked>> | 80% | 51,576 psi | 81% | 2933 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,454 psi | 70% | 2805 fps | 96.9% |
| IMR 7828 SSC | <<locked>> | 80% | 39,624 psi | 62% | 2795 fps | 96% |
| IMR 8133 Enduron | <<locked>> | 90% | 36,042 psi | 56% | 2743 fps | 95.1% |
| Lovex S070 | <<locked>> | 80% | 53,243 psi | 83% | 2956 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 36,970 psi | 58% | 2644 fps | 98.7% |
| Norma 204 | <<locked>> | 80% | 51,576 psi | 81% | 2972 fps | 99.3% |
| Norma 217 | <<locked>> | 86% | 32,053 psi | 50% | 2654 fps | 95.9% |
| Norma MRP | <<locked>> | 80% | 43,918 psi | 69% | 2904 fps | 99.3% |
| Norma URP | <<locked>> | 80% | 52,779 psi | 83% | 2976 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,508 psi | 62% | 2808 fps | 96.4% |
| Ramshot Hunter | <<locked>> | 80% | 51,706 psi | 81% | 2979 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,853 psi | 56% | 2690 fps | 97.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,182 psi | 46% | 1788 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 52,576 psi | 82% | 3038 fps | 100% |
| ReloadSwiss RS 76 | 99.6 gr | 80% | 33,750 psi | 53% | 2717 fps | 97.2% |
| ReloadSwiss RS 80 | 110.4 gr | 88% | 40,669 psi | 64% | 2864 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 46,238 psi | 72% | 2848 fps | 97.8% |
| Rottweil R 905 | <<locked>> | 80% | 45,005 psi | 71% | 2864 fps | 98.6% |
| Shooters World SW4350 | <<locked>> | 80% | 53,243 psi | 83% | 2956 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,708 psi | 84% | 2910 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,657 psi | 70% | 2858 fps | 98.5% |
| Somchem S361 | <<locked>> | 80% | 47,369 psi | 74% | 2838 fps | 97.4% |
| Somchem S365 | <<locked>> | 80% | 50,546 psi | 79% | 2930 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,847 psi | 72% | 2844 fps | 99.3% |
| Vihtavuori N160 | <<locked>> | 80% | 54,244 psi | 85% | 2966 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 40,045 psi | 63% | 2717 fps | 97.9% |
| Vihtavuori N170 | <<locked>> | 94% | 53,940 psi | 85% | 2995 fps | 95% |
| Vihtavuori N550 | <<locked>> | 80% | 53,751 psi | 84% | 2972 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,223 psi | 71% | 2861 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,671 psi | 68% | 2890 fps | 96.7% |
| Vihtavuori N565 | <<locked>> | 82% | 39,378 psi | 62% | 2776 fps | 95.7% |
| Vihtavuori N568 | <<locked>> | 88% | 41,858 psi | 66% | 2877 fps | 95.1% |
| Vihtavuori N570 | <<locked>> | 94% | 48,646 psi | 76% | 3058 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,287 psi | 84% | 2910 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,797 psi | 59% | 2841 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 42,018 psi | 66% | 2769 fps | 97.9% |
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 | 210gr | Impala RNFP KO. Hodgdon Retumbo delivers the highest muzzle velocity at 3,241 fps; across all powders the maximum-charge window runs from 1,949 fps to 3,241 fps. ADI AR 2225 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 210.0 gr projectile in 0.338" calls for a 1:15.0 twist; slower twists will usually not stabilise this weight. ADI AR 2225, Alliant Reloder-33, 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, ReloadSwiss RS 76, ReloadSwiss RS 80 rank at the top here: for .338-378 Weath. Mag. with the .338 | 210gr | Impala RNFP KO 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.