Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 270gr | NorthFork Bonded Core bullet and 88 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Norma MRP, Vihtavuori N560 and Accurate MAGPRO.
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.
A valid access license is required to use the Personalized Load Calculator.
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 2700 | <<locked>> | 82% | 56,057 psi | 88% | 2831 fps | 99.5% |
| Accurate 3100 | <<locked>> | 98% | 54,897 psi | 86% | 2887 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 55,811 psi | 87% | 2808 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 56,942 psi | 89% | 2930 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 57,188 psi | 90% | 3038 fps | 97.8% |
| ADI AR 2208 | <<locked>> | 84% | 55,477 psi | 87% | 2844 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 57,653 psi | 90% | 2982 fps | 99.3% |
| ADI AR 2213 | <<locked>> | 98% | 55,245 psi | 87% | 2982 fps | 98.2% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 38,174 psi | 60% | 2703 fps | 97.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 56,492 psi | 89% | 2864 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 56,637 psi | 89% | 2890 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 57,638 psi | 90% | 2982 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 55,259 psi | 87% | 2953 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 57,029 psi | 89% | 2969 fps | 99.3% |
| Alliant Reloder-22 | <<locked>> | 98% | 54,650 psi | 86% | 2976 fps | 99.2% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 55,535 psi | 87% | 2953 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 48,037 psi | 75% | 2897 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 55,724 psi | 87% | 3045 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 53,664 psi | 84% | 2959 fps | 99% |
| Bofors RP3 | <<locked>> | 84% | 57,421 psi | 90% | 2881 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 43,918 psi | 69% | 2818 fps | 96.6% |
| Bofors RP5 | <<locked>> | 98% | 54,650 psi | 86% | 2976 fps | 99.2% |
| Bofors RP7 | <<locked>> | 88% | 56,594 psi | 89% | 2877 fps | 99.6% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 47,558 psi | 75% | 2838 fps | 97.5% |
| Hodgdon H380 | <<locked>> | 82% | 54,070 psi | 85% | 2851 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 55,274 psi | 87% | 2930 fps | 99.8% |
| Hodgdon H4350 | <<locked>> | 86% | 54,723 psi | 86% | 2887 fps | 99.2% |
| Hodgdon H4831 | <<locked>> | 96% | 55,492 psi | 87% | 2923 fps | 97.7% |
| Hodgdon H4831 SC | <<locked>> | 96% | 54,346 psi | 85% | 2904 fps | 97.4% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 54,389 psi | 85% | 2854 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 47,036 psi | 74% | 2943 fps | 98.8% |
| Hodgdon Superformance | <<locked>> | 88% | 55,463 psi | 87% | 2969 fps | 99.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,709 psi | 58% | 1788 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 54,897 psi | 86% | 2825 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 57,290 psi | 90% | 2864 fps | 99.8% |
| IMR 4350 | <<locked>> | 90% | 54,331 psi | 85% | 2861 fps | 99.5% |
| IMR 4451 Enduron | <<locked>> | 86% | 54,665 psi | 86% | 2851 fps | 99.7% |
| IMR 4831 | <<locked>> | 92% | 57,290 psi | 90% | 2920 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 56,782 psi | 89% | 2907 fps | 98% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 56,637 psi | 89% | 3015 fps | 98.6% |
| Lovex S062 | <<locked>> | 82% | 55,201 psi | 87% | 2815 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 55,085 psi | 86% | 2848 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 56,376 psi | 88% | 2890 fps | 99.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 48,979 psi | 77% | 2795 fps | 99.7% |
| Norma 203B | <<locked>> | 82% | 55,927 psi | 88% | 2874 fps | 100% |
| Norma 204 | <<locked>> | 90% | 55,027 psi | 86% | 2917 fps | 98.9% |
| Norma MRP | <<locked>> | 96% | 54,404 psi | 85% | 3002 fps | 99.8% |
| Norma URP | <<locked>> | 90% | 55,376 psi | 87% | 2913 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 56,884 psi | 89% | 2904 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 57,406 psi | 90% | 3038 fps | 98.9% |
| Ramshot Hunter | <<locked>> | 90% | 54,215 psi | 85% | 2920 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 51,372 psi | 81% | 2907 fps | 99.3% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,405 psi | 59% | 1831 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 57,479 psi | 90% | 2890 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 54,607 psi | 86% | 2940 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 56,811 psi | 89% | 2953 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 55,158 psi | 86% | 2986 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 47,137 psi | 74% | 2940 fps | 99.5% |
| Rottweil R 902 | <<locked>> | 82% | 57,087 psi | 89% | 2828 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 57,638 psi | 90% | 2881 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 55,622 psi | 87% | 2897 fps | 98.3% |
| Rottweil R 905 | <<locked>> | 96% | 56,434 psi | 88% | 2956 fps | 99.3% |
| Rottweil R 907 | <<locked>> | 88% | 56,594 psi | 89% | 2877 fps | 99.6% |
| Shooters World Long Rifle | <<locked>> | 88% | 55,085 psi | 86% | 2848 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 55,201 psi | 87% | 2815 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 56,376 psi | 88% | 2890 fps | 99.9% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 55,535 psi | 87% | 2890 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 54,607 psi | 86% | 2707 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 54,433 psi | 85% | 2802 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 55,970 psi | 88% | 2953 fps | 99.3% |
| Somchem S355 | <<locked>> | 86% | 57,435 psi | 90% | 2874 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 57,290 psi | 90% | 2887 fps | 97.9% |
| Somchem S365 | <<locked>> | 92% | 55,216 psi | 87% | 2917 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 57,072 psi | 89% | 2930 fps | 99.7% |
| Vihtavuori N135 | <<locked>> | 82% | 57,638 psi | 90% | 2779 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 57,711 psi | 90% | 2795 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 55,085 psi | 86% | 2799 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 57,435 psi | 90% | 2904 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 56,463 psi | 88% | 2907 fps | 99.5% |
| Vihtavuori N540 | <<locked>> | 82% | 55,898 psi | 88% | 2795 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 56,565 psi | 89% | 2913 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 54,375 psi | 85% | 2930 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 54,549 psi | 85% | 2995 fps | 97.8% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 50,111 psi | 79% | 2904 fps | 97.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 57,101 psi | 89% | 2867 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 55,405 psi | 87% | 2933 fps | 99.8% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 51,459 psi | 81% | 3028 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 57,116 psi | 90% | 2923 fps | 99.2% |
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 2700 | <<locked>> | 80% | 52,417 psi | 82% | 2776 fps | 99.1% |
| Accurate 3100 | <<locked>> | 80% | 29,950 psi | 47% | 2395 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 52,402 psi | 82% | 2762 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 40,567 psi | 64% | 2657 fps | 99.5% |
| Accurate MAGPRO | 109.1 gr | 92% | 46,253 psi | 72% | 2851 fps | 95.3% |
| ADI AR 2208 | <<locked>> | 80% | 48,979 psi | 77% | 2743 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 38,943 psi | 61% | 2638 fps | 95.5% |
| ADI AR 2213 | <<locked>> | 90% | 42,322 psi | 66% | 2736 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 96% | 33,663 psi | 53% | 2582 fps | 95.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 49,821 psi | 78% | 2766 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 53,171 psi | 83% | 2838 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 39,059 psi | 61% | 2661 fps | 99.6% |
| Alliant Reloder-17 | <<locked>> | 80% | 44,599 psi | 70% | 2785 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 38,754 psi | 61% | 2631 fps | 95.6% |
| Alliant Reloder-22 | <<locked>> | 88% | 39,175 psi | 61% | 2687 fps | 95.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 28,848 psi | 45% | 2428 fps | 98.3% |
| Alliant Reloder-25 | <<locked>> | 86% | 30,647 psi | 48% | 2493 fps | 96% |
| Alliant Reloder-26 | <<locked>> | 80% | 31,009 psi | 49% | 2546 fps | 97.1% |
| Bofors RP15 | <<locked>> | 90% | 38,667 psi | 61% | 2674 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 50,401 psi | 79% | 2782 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 41,017 psi | 64% | 2759 fps | 95.7% |
| Bofors RP5 | <<locked>> | 88% | 39,175 psi | 61% | 2687 fps | 95.9% |
| Bofors RP7 | <<locked>> | 80% | 44,048 psi | 69% | 2664 fps | 98% |
| Hodgdon H1000 | <<locked>> | 96% | 41,553 psi | 65% | 2717 fps | 95.7% |
| Hodgdon H380 | <<locked>> | 80% | 50,633 psi | 79% | 2799 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 42,337 psi | 66% | 2703 fps | 98.2% |
| Hodgdon H4350 | <<locked>> | 80% | 45,092 psi | 71% | 2717 fps | 97.6% |
| Hodgdon H4831 | <<locked>> | 90% | 45,339 psi | 71% | 2746 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 90% | 44,411 psi | 70% | 2730 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 36,782 psi | 58% | 2552 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 92% | 36,289 psi | 57% | 2687 fps | 95.1% |
| Hodgdon Superformance | <<locked>> | 80% | 41,336 psi | 65% | 2720 fps | 97.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,485 psi | 43% | 1598 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 51,517 psi | 81% | 2776 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 53,708 psi | 84% | 2808 fps | 99.6% |
| IMR 4350 | <<locked>> | 80% | 39,682 psi | 62% | 2592 fps | 96.9% |
| IMR 4451 Enduron | <<locked>> | 80% | 45,455 psi | 71% | 2690 fps | 98.6% |
| IMR 4831 | <<locked>> | 80% | 38,812 psi | 61% | 2605 fps | 99.3% |
| IMR 4955 Enduron | <<locked>> | 88% | 44,324 psi | 69% | 2690 fps | 95.3% |
| IMR 7828 SSC | <<locked>> | 92% | 43,308 psi | 68% | 2772 fps | 95.6% |
| Lovex S062 | <<locked>> | 80% | 51,880 psi | 81% | 2769 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 42,989 psi | 67% | 2641 fps | 99.1% |
| Lovex S070 | <<locked>> | 80% | 41,292 psi | 65% | 2628 fps | 98% |
| Lovex S071 | <<locked>> | 86% | 31,270 psi | 49% | 2431 fps | 95.8% |
| Norma 203B | <<locked>> | 80% | 52,562 psi | 82% | 2825 fps | 100% |
| Norma 204 | <<locked>> | 80% | 39,247 psi | 62% | 2621 fps | 95.5% |
| Norma MRP | 95.5 gr | 82% | 33,446 psi | 52% | 2575 fps | 95.2% |
| Norma URP | <<locked>> | 80% | 40,089 psi | 63% | 2648 fps | 99.4% |
| Ramshot Big Game | <<locked>> | 80% | 53,142 psi | 83% | 2848 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 43,018 psi | 67% | 2779 fps | 95.9% |
| Ramshot Hunter | <<locked>> | 80% | 38,914 psi | 61% | 2638 fps | 98.1% |
| Ramshot Magnum | <<locked>> | 90% | 35,694 psi | 56% | 2595 fps | 95.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,065 psi | 44% | 1637 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 50,531 psi | 79% | 2782 fps | 99.6% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 47,369 psi | 74% | 2831 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 40,219 psi | 63% | 2674 fps | 99.3% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 38,870 psi | 61% | 2684 fps | 99% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 35,592 psi | 56% | 2671 fps | 96.2% |
| Rottweil R 902 | <<locked>> | 80% | 53,795 psi | 84% | 2779 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 47,529 psi | 74% | 2730 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 43,120 psi | 68% | 2674 fps | 95.6% |
| Rottweil R 905 | <<locked>> | 84% | 37,913 psi | 59% | 2615 fps | 95.5% |
| Rottweil R 907 | <<locked>> | 80% | 44,048 psi | 69% | 2664 fps | 98% |
| Shooters World Long Rifle | <<locked>> | 80% | 42,989 psi | 67% | 2641 fps | 99.1% |
| Shooters World Precision | <<locked>> | 80% | 51,880 psi | 81% | 2769 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 41,292 psi | 65% | 2628 fps | 98% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 48,704 psi | 76% | 2785 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 48,298 psi | 76% | 2618 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 42,163 psi | 66% | 2589 fps | 98.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 37,550 psi | 59% | 2608 fps | 95.3% |
| Somchem S355 | <<locked>> | 80% | 47,558 psi | 75% | 2726 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 47,036 psi | 74% | 2720 fps | 95.8% |
| Somchem S365 | <<locked>> | 80% | 36,695 psi | 57% | 2605 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 36,129 psi | 57% | 2546 fps | 95.8% |
| Vihtavuori N135 | <<locked>> | 80% | 54,186 psi | 85% | 2733 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 54,244 psi | 85% | 2749 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 45,498 psi | 71% | 2654 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 41,524 psi | 65% | 2644 fps | 99.6% |
| Vihtavuori N165 | <<locked>> | 86% | 35,592 psi | 56% | 2526 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 52,446 psi | 82% | 2749 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 40,886 psi | 64% | 2644 fps | 99.4% |
| Vihtavuori N555 | <<locked>> | 80% | 32,126 psi | 50% | 2503 fps | 98.3% |
| Vihtavuori N560 | 104.8 gr | 90% | 44,411 psi | 70% | 2812 fps | 95.5% |
| Vihtavuori N565 | <<locked>> | 96% | 43,685 psi | 68% | 2785 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 40,509 psi | 63% | 2608 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 42,453 psi | 67% | 2703 fps | 98.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 25,570 psi | 40% | 2418 fps | 97.9% |
| Winchester Supreme 780 | <<locked>> | 86% | 37,710 psi | 59% | 2579 fps | 95.2% |
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 88 powders for .378 Weath. Mag. loaded with the .375 | 270gr | NorthFork Bonded Core. Alliant Reloder-26 delivers the highest muzzle velocity at 3,045 fps; across all powders the maximum-charge window runs from 1,788 fps to 3,045 fps. ADI AR 2225 gives the best case fill at 100 %, and 88 of the 88 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 58–90 %, 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 2225, Alliant Reloder-23, 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. Norma MRP, Vihtavuori N560, Accurate MAGPRO rank at the top here: for .378 Weath. Mag. with the .375 | 270gr | NorthFork Bonded Core 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.