Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 270gr | Impala RNFP KO bullet and 80 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, Accurate MAGPRO and Accurate High Country.
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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You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 96% | 54,839 psi | 86% | 2864 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 56,507 psi | 89% | 2900 fps | 100% |
| Accurate High Country | <<locked>> | 94% | 55,245 psi | 87% | 3002 fps | 98.4% |
| Accurate MAGPRO | <<locked>> | 96% | 56,159 psi | 88% | 3002 fps | 97.4% |
| ADI AR 2208 | <<locked>> | 84% | 57,464 psi | 90% | 2854 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 56,260 psi | 88% | 2943 fps | 99.1% |
| ADI AR 2213 | <<locked>> | 98% | 57,638 psi | 90% | 2999 fps | 98.5% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 45,556 psi | 71% | 2772 fps | 96.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 40,785 psi | 64% | 2743 fps | 98.1% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 56,478 psi | 89% | 2936 fps | 99.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 55,695 psi | 87% | 2831 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 56,144 psi | 88% | 2946 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 57,682 psi | 90% | 2966 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 55,811 psi | 87% | 2930 fps | 99.1% |
| Alliant Reloder-22 | <<locked>> | 98% | 57,290 psi | 90% | 2999 fps | 99.4% |
| Alliant Reloder-23 | <<locked>> | 98% | 54,679 psi | 86% | 2923 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 50,575 psi | 79% | 2923 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 54,723 psi | 86% | 3015 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 56,159 psi | 88% | 2979 fps | 99.2% |
| Bofors RP3 | <<locked>> | 82% | 56,942 psi | 89% | 2851 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 46,775 psi | 73% | 2854 fps | 97.2% |
| Bofors RP5 | <<locked>> | 98% | 57,290 psi | 90% | 2999 fps | 99.4% |
| Bofors RP7 | <<locked>> | 86% | 55,680 psi | 87% | 2841 fps | 99.5% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 49,951 psi | 78% | 2861 fps | 97.9% |
| Hodgdon H380 | <<locked>> | 82% | 56,782 psi | 89% | 2867 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 57,580 psi | 90% | 2946 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 86% | 56,913 psi | 89% | 2900 fps | 99.3% |
| Hodgdon H4831 | <<locked>> | 96% | 57,595 psi | 90% | 2936 fps | 97.9% |
| Hodgdon H4831 SC | <<locked>> | 96% | 56,623 psi | 89% | 2920 fps | 97.7% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 56,840 psi | 89% | 2867 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 49,574 psi | 78% | 2976 fps | 99.1% |
| Hodgdon Superformance | <<locked>> | 88% | 57,740 psi | 90% | 2986 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,115 psi | 58% | 1781 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 57,087 psi | 89% | 2835 fps | 100% |
| IMR 4350 | <<locked>> | 90% | 56,478 psi | 89% | 2877 fps | 99.6% |
| IMR 4451 Enduron | <<locked>> | 86% | 56,710 psi | 89% | 2861 fps | 99.8% |
| IMR 4831 | <<locked>> | 90% | 56,536 psi | 89% | 2887 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 55,550 psi | 87% | 2867 fps | 97.7% |
| IMR 7828 SSC | <<locked>> | 98% | 55,303 psi | 87% | 2972 fps | 98.2% |
| Lovex S065 | <<locked>> | 88% | 57,508 psi | 90% | 2864 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 55,767 psi | 87% | 2861 fps | 99.8% |
| Lovex S071ᴾ | <<locked>> | 100% | 52,402 psi | 82% | 2828 fps | 99.9% |
| Norma 204 | <<locked>> | 90% | 57,188 psi | 90% | 2930 fps | 99.1% |
| Norma 217ᴾ | <<locked>> | 100% | 36,666 psi | 57% | 2677 fps | 96.2% |
| Norma MRP | <<locked>> | 96% | 57,029 psi | 89% | 3025 fps | 99.9% |
| Norma URP | <<locked>> | 88% | 54,650 psi | 86% | 2881 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 55,898 psi | 88% | 2995 fps | 98.6% |
| Ramshot Hunter | <<locked>> | 90% | 56,536 psi | 89% | 2933 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 54,027 psi | 85% | 2930 fps | 99.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,927 psi | 59% | 1824 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 56,289 psi | 88% | 2851 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 56,956 psi | 89% | 2953 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 55,869 psi | 88% | 2920 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 57,537 psi | 90% | 2999 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 49,893 psi | 78% | 2972 fps | 99.7% |
| Rottweil R 903 | <<locked>> | 84% | 57,087 psi | 89% | 2851 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 54,418 psi | 85% | 2854 fps | 98% |
| Rottweil R 905 | <<locked>> | 94% | 55,376 psi | 87% | 2920 fps | 99.1% |
| Rottweil R 907 | <<locked>> | 86% | 55,680 psi | 87% | 2841 fps | 99.5% |
| Shooters World Long Rifle | <<locked>> | 88% | 57,508 psi | 90% | 2864 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 55,767 psi | 87% | 2861 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 54,418 psi | 85% | 2854 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 56,753 psi | 89% | 2717 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 56,985 psi | 89% | 2815 fps | 99.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 54,897 psi | 86% | 2913 fps | 99.1% |
| Somchem S355 | <<locked>> | 84% | 56,623 psi | 89% | 2841 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 56,014 psi | 88% | 2848 fps | 97.5% |
| Somchem S365 | <<locked>> | 90% | 54,404 psi | 85% | 2884 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 56,202 psi | 88% | 2897 fps | 99.6% |
| Vihtavuori N150 | <<locked>> | 86% | 57,682 psi | 90% | 2812 fps | 100% |
| Vihtavuori N160 | <<locked>> | 88% | 56,318 psi | 88% | 2867 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 55,332 psi | 87% | 2871 fps | 99.3% |
| Vihtavuori N550 | <<locked>> | 88% | 55,651 psi | 87% | 2877 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 57,653 psi | 90% | 2953 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 56,985 psi | 89% | 3015 fps | 98.1% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 53,185 psi | 83% | 2936 fps | 97.7% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 55,564 psi | 87% | 2828 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 54,317 psi | 85% | 2897 fps | 99.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 54,404 psi | 85% | 3054 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 55,840 psi | 88% | 2887 fps | 99% |
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% | 33,301 psi | 52% | 2454 fps | 96.5% |
| Accurate 4350 | <<locked>> | 80% | 43,816 psi | 69% | 2694 fps | 99.8% |
| Accurate High Country | 98.5 gr | 86% | 42,482 psi | 67% | 2766 fps | 95.6% |
| Accurate MAGPRO | 105.1 gr | 90% | 45,934 psi | 72% | 2822 fps | 95.1% |
| ADI AR 2208 | <<locked>> | 80% | 51,213 psi | 80% | 2759 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 38,899 psi | 61% | 2612 fps | 95.3% |
| ADI AR 2213 | <<locked>> | 90% | 44,701 psi | 70% | 2766 fps | 95.7% |
| ADI AR 2217 | <<locked>> | 98% | 42,815 psi | 67% | 2713 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 94% | 34,272 psi | 54% | 2575 fps | 95.5% |
| Alliant Power Pro Varmint | <<locked>> | 82% | 39,059 psi | 61% | 2615 fps | 95.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 52,388 psi | 82% | 2785 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 41,510 psi | 65% | 2690 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 47,137 psi | 74% | 2808 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 38,696 psi | 61% | 2608 fps | 95.4% |
| Alliant Reloder-22 | <<locked>> | 86% | 39,334 psi | 62% | 2667 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,575 psi | 49% | 2477 fps | 99.1% |
| Alliant Reloder-25 | <<locked>> | 82% | 29,718 psi | 47% | 2438 fps | 95.4% |
| Alliant Reloder-26 | 94.4 gr | 80% | 33,924 psi | 53% | 2602 fps | 98.2% |
| Bofors RP15 | <<locked>> | 88% | 39,001 psi | 61% | 2657 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 53,505 psi | 84% | 2805 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 41,278 psi | 65% | 2743 fps | 95.6% |
| Bofors RP5 | <<locked>> | 86% | 39,334 psi | 62% | 2667 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 46,586 psi | 73% | 2687 fps | 98.4% |
| Hodgdon H1000 | <<locked>> | 94% | 41,234 psi | 65% | 2687 fps | 95.4% |
| Hodgdon H380 | <<locked>> | 80% | 53,403 psi | 84% | 2818 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 44,831 psi | 70% | 2730 fps | 98.6% |
| Hodgdon H4350 | <<locked>> | 80% | 47,384 psi | 74% | 2740 fps | 98% |
| Hodgdon H4831 | <<locked>> | 88% | 44,701 psi | 70% | 2713 fps | 95% |
| Hodgdon H4831 SC | <<locked>> | 90% | 46,731 psi | 73% | 2753 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 39,363 psi | 62% | 2582 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 36,695 psi | 57% | 2674 fps | 95.2% |
| Hodgdon Superformance | <<locked>> | 80% | 43,772 psi | 69% | 2746 fps | 98.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,905 psi | 44% | 1591 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 53,911 psi | 84% | 2789 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 41,989 psi | 66% | 2618 fps | 97.5% |
| IMR 4451 Enduron | <<locked>> | 80% | 47,543 psi | 75% | 2707 fps | 98.8% |
| IMR 4831 | <<locked>> | 80% | 41,669 psi | 65% | 2638 fps | 99.7% |
| IMR 4955 Enduron | <<locked>> | 86% | 43,758 psi | 69% | 2657 fps | 95% |
| IMR 7828 SSC | <<locked>> | 90% | 43,033 psi | 67% | 2743 fps | 95.3% |
| Lovex S065 | <<locked>> | 80% | 45,614 psi | 71% | 2667 fps | 99.4% |
| Lovex S070 | <<locked>> | 80% | 44,077 psi | 69% | 2657 fps | 98.5% |
| Lovex S071 | <<locked>> | 82% | 30,893 psi | 48% | 2392 fps | 95.5% |
| Norma 204 | <<locked>> | 80% | 41,597 psi | 65% | 2651 fps | 96.1% |
| Norma 217 | <<locked>> | 98% | 34,650 psi | 54% | 2625 fps | 95.2% |
| Norma MRP | <<locked>> | 80% | 33,968 psi | 53% | 2566 fps | 95.4% |
| Norma URP | <<locked>> | 80% | 42,772 psi | 67% | 2677 fps | 99.7% |
| Ramshot Grand | <<locked>> | 90% | 42,772 psi | 67% | 2753 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 41,394 psi | 65% | 2667 fps | 98.6% |
| Ramshot Magnum | <<locked>> | 88% | 36,042 psi | 56% | 2579 fps | 95.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,572 psi | 45% | 1634 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 52,924 psi | 83% | 2799 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 49,806 psi | 78% | 2851 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 43,163 psi | 68% | 2707 fps | 99.7% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 41,350 psi | 65% | 2717 fps | 99.4% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 33,779 psi | 53% | 2592 fps | 95% |
| Rottweil R 903 | <<locked>> | 80% | 50,618 psi | 79% | 2753 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 42,714 psi | 67% | 2641 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 82% | 38,218 psi | 60% | 2598 fps | 95.5% |
| Rottweil R 907 | <<locked>> | 80% | 46,586 psi | 73% | 2687 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 80% | 45,614 psi | 71% | 2667 fps | 99.4% |
| Shooters World SW4350 | <<locked>> | 80% | 44,077 psi | 69% | 2657 fps | 98.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 51,111 psi | 80% | 2802 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 50,546 psi | 79% | 2631 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,701 psi | 70% | 2612 fps | 98.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 37,869 psi | 59% | 2592 fps | 95.3% |
| Somchem S355 | <<locked>> | 80% | 50,328 psi | 79% | 2746 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 46,470 psi | 73% | 2687 fps | 95.5% |
| Somchem S365 | <<locked>> | 80% | 39,595 psi | 62% | 2641 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,724 psi | 58% | 2533 fps | 95.9% |
| Vihtavuori N150 | <<locked>> | 80% | 48,167 psi | 75% | 2674 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,005 psi | 69% | 2667 fps | 99.8% |
| Vihtavuori N165 | <<locked>> | 84% | 35,897 psi | 56% | 2510 fps | 95.2% |
| Vihtavuori N550 | <<locked>> | 80% | 43,642 psi | 68% | 2677 fps | 99.7% |
| Vihtavuori N555 | <<locked>> | 80% | 35,389 psi | 55% | 2556 fps | 99.1% |
| Vihtavuori N560 | <<locked>> | 88% | 44,019 psi | 69% | 2779 fps | 95.2% |
| Vihtavuori N565 | <<locked>> | 94% | 43,874 psi | 69% | 2769 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 42,728 psi | 67% | 2631 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 44,962 psi | 70% | 2730 fps | 98.6% |
| Winchester StaBALL HD | <<locked>> | 80% | 28,384 psi | 44% | 2490 fps | 99.2% |
| Winchester Supreme 780 | <<locked>> | 84% | 37,811 psi | 59% | 2559 fps | 95.1% |
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 80 powders for .378 Weath. Mag. loaded with the .375 | 270gr | Impala RNFP KO. Winchester StaBALL HD delivers the highest muzzle velocity at 3,054 fps; across all powders the maximum-charge window runs from 1,781 fps to 3,054 fps. ADI AR 2217 gives the best case fill at 100 %, and 80 of the 80 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 270.0 gr projectile in 0.375" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Alliant Reloder-25 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. Alliant Reloder-26, Accurate MAGPRO, Accurate High Country rank at the top here: for .378 Weath. Mag. with the .375 | 270gr | 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.