Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 250gr | Speer TBBC bullet and 93 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, Norma MRP and ReloadSwiss RS 70.
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 2495 | <<locked>> | 82% | 56,202 psi | 88% | 2874 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 57,319 psi | 90% | 2953 fps | 99.2% |
| Accurate 3100ᴾ | <<locked>> | 100% | 55,550 psi | 87% | 2999 fps | 99.9% |
| Accurate 4064 | <<locked>> | 84% | 56,637 psi | 89% | 2930 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 57,711 psi | 90% | 3048 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 53,867 psi | 84% | 3084 fps | 96.3% |
| ADI AR 2208 | <<locked>> | 86% | 56,521 psi | 89% | 2969 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 54,795 psi | 86% | 3038 fps | 98.5% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 56,289 psi | 88% | 3094 fps | 97.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 56,101 psi | 88% | 3097 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 57,537 psi | 90% | 2992 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 57,667 psi | 90% | 3015 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 54,621 psi | 86% | 3051 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 56,043 psi | 88% | 3074 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 54,215 psi | 85% | 3028 fps | 98.4% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 55,288 psi | 87% | 3091 fps | 98.7% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 52,199 psi | 82% | 3015 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 45,324 psi | 71% | 2943 fps | 99.5% |
| Alliant Reloder-26 | <<locked>> | 98% | 56,260 psi | 88% | 3166 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 50,589 psi | 79% | 3009 fps | 97.9% |
| Bofors RP3 | <<locked>> | 84% | 54,781 psi | 86% | 2956 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 55,288 psi | 87% | 3091 fps | 98.7% |
| Bofors RP7 | <<locked>> | 90% | 57,711 psi | 90% | 2999 fps | 99.4% |
| Hodgdon H380 | <<locked>> | 84% | 55,216 psi | 87% | 2976 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 56,043 psi | 88% | 3048 fps | 99.6% |
| Hodgdon H4350 | <<locked>> | 88% | 55,709 psi | 87% | 3005 fps | 98.8% |
| Hodgdon H4831 | <<locked>> | 98% | 56,347 psi | 88% | 3035 fps | 97.1% |
| Hodgdon H4831 SC | <<locked>> | 98% | 55,201 psi | 87% | 3015 fps | 96.8% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 54,998 psi | 86% | 2972 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 56,478 psi | 89% | 3009 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 44,338 psi | 69% | 2976 fps | 97.2% |
| Hodgdon Superformance | <<locked>> | 90% | 56,434 psi | 88% | 3087 fps | 99.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,506 psi | 57% | 1857 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 56,855 psi | 89% | 2969 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 55,956 psi | 88% | 2949 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 54,955 psi | 86% | 2933 fps | 99.4% |
| IMR 4350 | <<locked>> | 92% | 55,288 psi | 87% | 2979 fps | 99.2% |
| IMR 4451 Enduron | <<locked>> | 88% | 55,738 psi | 87% | 2969 fps | 99.4% |
| IMR 4831 | <<locked>> | 92% | 54,317 psi | 85% | 2986 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 55,506 psi | 87% | 2989 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 54,259 psi | 85% | 2963 fps | 96.8% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 53,563 psi | 84% | 3061 fps | 97.3% |
| Lovex S060 | <<locked>> | 82% | 57,348 psi | 90% | 2930 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 56,217 psi | 88% | 2940 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 55,999 psi | 88% | 2966 fps | 99.9% |
| Lovex S070 | <<locked>> | 92% | 57,334 psi | 90% | 3012 fps | 99.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 46,137 psi | 72% | 2844 fps | 99% |
| Norma 201 | <<locked>> | 82% | 57,479 psi | 90% | 2949 fps | 100% |
| Norma 203B | <<locked>> | 84% | 56,956 psi | 89% | 3002 fps | 100% |
| Norma 204 | <<locked>> | 92% | 56,043 psi | 88% | 3031 fps | 98.5% |
| Norma MRP | <<locked>> | 98% | 54,882 psi | 86% | 3117 fps | 99.5% |
| Norma URP | <<locked>> | 92% | 56,217 psi | 88% | 3031 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 54,186 psi | 85% | 2972 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 54,157 psi | 85% | 3081 fps | 97.7% |
| Ramshot Hunter | <<locked>> | 92% | 54,984 psi | 86% | 3035 fps | 99.8% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 48,312 psi | 76% | 2949 fps | 98.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,144 psi | 58% | 1900 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 54,998 psi | 86% | 2956 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 55,434 psi | 87% | 3068 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 57,638 psi | 90% | 3074 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 55,999 psi | 88% | 3107 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 44,396 psi | 70% | 2972 fps | 98.3% |
| Rottweil R 902 | <<locked>> | 82% | 54,737 psi | 86% | 2900 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 54,911 psi | 86% | 2953 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 56,521 psi | 89% | 3009 fps | 97.7% |
| Rottweil R 905 | <<locked>> | 98% | 57,087 psi | 89% | 3068 fps | 98.9% |
| Rottweil R 907 | <<locked>> | 90% | 57,711 psi | 90% | 2999 fps | 99.4% |
| Shooters World Long Rifle | <<locked>> | 90% | 55,999 psi | 88% | 2966 fps | 99.9% |
| Shooters World Precision | <<locked>> | 84% | 56,217 psi | 88% | 2940 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 57,334 psi | 90% | 3012 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 56,449 psi | 88% | 3015 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 57,421 psi | 90% | 2986 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 55,782 psi | 87% | 2831 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 55,622 psi | 87% | 2917 fps | 99.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 56,594 psi | 89% | 3064 fps | 98.9% |
| Somchem S355 | <<locked>> | 86% | 54,766 psi | 86% | 2946 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 54,737 psi | 86% | 2943 fps | 96.7% |
| Somchem S365 | <<locked>> | 94% | 55,666 psi | 87% | 3035 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 54,186 psi | 85% | 2989 fps | 99.1% |
| Vihtavuori N135 | <<locked>> | 82% | 55,158 psi | 86% | 2858 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 55,288 psi | 87% | 2874 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 56,101 psi | 88% | 2920 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 54,737 psi | 86% | 2972 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 53,374 psi | 84% | 2959 fps | 98.7% |
| Vihtavuori N540 | <<locked>> | 84% | 57,145 psi | 90% | 2923 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 57,508 psi | 90% | 3031 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 54,694 psi | 86% | 3041 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 55,129 psi | 86% | 3104 fps | 97.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 54,302 psi | 85% | 2936 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 56,202 psi | 88% | 3051 fps | 99.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 47,340 psi | 74% | 3081 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 57,696 psi | 90% | 2992 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 54,186 psi | 85% | 2979 fps | 98.3% |
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 2495 | <<locked>> | 80% | 52,721 psi | 83% | 2825 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 50,256 psi | 79% | 2838 fps | 98.3% |
| Accurate 3100 | <<locked>> | 84% | 32,242 psi | 51% | 2543 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 49,937 psi | 78% | 2835 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,261 psi | 60% | 2707 fps | 98.7% |
| Accurate MAGPRO | <<locked>> | 96% | 50,125 psi | 79% | 3018 fps | 95.4% |
| ADI AR 2208 | <<locked>> | 80% | 46,934 psi | 74% | 2808 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 88% | 42,264 psi | 66% | 2802 fps | 95.6% |
| ADI AR 2213 | <<locked>> | 94% | 45,919 psi | 72% | 2904 fps | 95.2% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 52,243 psi | 82% | 3038 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,601 psi | 75% | 2835 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,836 psi | 80% | 2907 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 37,101 psi | 58% | 2713 fps | 98.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 42,206 psi | 66% | 2841 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 41,872 psi | 66% | 2792 fps | 95.6% |
| Alliant Reloder-22 | <<locked>> | 90% | 39,552 psi | 62% | 2785 fps | 95% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,282 psi | 43% | 2461 fps | 96.7% |
| Alliant Reloder-25 | <<locked>> | 88% | 30,995 psi | 49% | 2585 fps | 95% |
| Alliant Reloder-26 | 97 gr | 80% | 29,182 psi | 46% | 2575 fps | 95% |
| Bofors RP15 | <<locked>> | 94% | 41,597 psi | 65% | 2831 fps | 95.6% |
| Bofors RP3 | <<locked>> | 80% | 48,080 psi | 75% | 2848 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 39,552 psi | 62% | 2785 fps | 95% |
| Bofors RP7 | <<locked>> | 80% | 42,119 psi | 66% | 2717 fps | 96.8% |
| Hodgdon H380 | <<locked>> | 80% | 48,254 psi | 76% | 2858 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 80% | 40,118 psi | 63% | 2749 fps | 96.8% |
| Hodgdon H4350 | <<locked>> | 80% | 43,062 psi | 67% | 2772 fps | 96.3% |
| Hodgdon H4831 | <<locked>> | 94% | 49,168 psi | 77% | 2913 fps | 95.5% |
| Hodgdon H4831 SC | <<locked>> | 94% | 48,182 psi | 76% | 2894 fps | 95.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,650 psi | 54% | 2602 fps | 99.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 52,736 psi | 83% | 2953 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 39,001 psi | 61% | 2844 fps | 95.2% |
| Hodgdon Superformance | <<locked>> | 80% | 39,117 psi | 61% | 2762 fps | 96.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,282 psi | 43% | 1660 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,432 psi | 84% | 2917 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,371 psi | 77% | 2841 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,721 psi | 81% | 2877 fps | 99% |
| IMR 4350 | <<locked>> | 80% | 37,797 psi | 59% | 2641 fps | 95.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,540 psi | 68% | 2749 fps | 97.5% |
| IMR 4831 | <<locked>> | 80% | 36,724 psi | 58% | 2654 fps | 98.4% |
| IMR 4895 | <<locked>> | 80% | 52,141 psi | 82% | 2936 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 48,008 psi | 75% | 2854 fps | 95.4% |
| IMR 7828 SSC | <<locked>> | 96% | 46,876 psi | 73% | 2936 fps | 95.6% |
| Lovex S060 | <<locked>> | 80% | 53,969 psi | 85% | 2881 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,661 psi | 78% | 2838 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,075 psi | 64% | 2697 fps | 98.2% |
| Lovex S070 | <<locked>> | 80% | 39,334 psi | 62% | 2680 fps | 96.8% |
| Lovex S071 | <<locked>> | 90% | 33,431 psi | 52% | 2572 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 54,041 psi | 85% | 2900 fps | 100% |
| Norma 203B | <<locked>> | 80% | 50,169 psi | 79% | 2894 fps | 100% |
| Norma 204 | <<locked>> | 84% | 42,714 psi | 67% | 2789 fps | 95.6% |
| Norma MRP | 101.2 gr | 86% | 36,158 psi | 57% | 2736 fps | 95.3% |
| Norma URP | <<locked>> | 80% | 37,971 psi | 60% | 2697 fps | 98.5% |
| Ramshot Big Game | <<locked>> | 80% | 50,647 psi | 79% | 2917 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 43,656 psi | 68% | 2881 fps | 95% |
| Ramshot Hunter | <<locked>> | 80% | 36,782 psi | 58% | 2684 fps | 96.7% |
| Ramshot Magnum | <<locked>> | 94% | 38,754 psi | 61% | 2753 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,804 psi | 44% | 1699 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 48,254 psi | 76% | 2844 fps | 99% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,817 psi | 70% | 2897 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,985 psi | 60% | 2723 fps | 98.4% |
| ReloadSwiss RS 70 | 96.1 gr | 80% | 36,840 psi | 58% | 2730 fps | 97.9% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 35,926 psi | 56% | 2756 fps | 95% |
| Rottweil R 902 | <<locked>> | 80% | 51,561 psi | 81% | 2854 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 45,194 psi | 71% | 2792 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 46,630 psi | 73% | 2835 fps | 95.6% |
| Rottweil R 905 | <<locked>> | 88% | 41,060 psi | 64% | 2779 fps | 95.6% |
| Rottweil R 907 | <<locked>> | 80% | 42,119 psi | 66% | 2717 fps | 96.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,075 psi | 64% | 2697 fps | 98.2% |
| Shooters World Precision | <<locked>> | 80% | 49,661 psi | 78% | 2838 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 39,334 psi | 62% | 2680 fps | 96.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 46,282 psi | 73% | 2848 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 53,737 psi | 84% | 2930 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,369 psi | 73% | 2694 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,248 psi | 63% | 2641 fps | 96.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 40,669 psi | 64% | 2772 fps | 95.4% |
| Somchem S355 | <<locked>> | 80% | 45,440 psi | 71% | 2792 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 47,950 psi | 75% | 2825 fps | 95.1% |
| Somchem S365 | <<locked>> | 80% | 34,447 psi | 54% | 2654 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 36,506 psi | 57% | 2644 fps | 95% |
| Vihtavuori N135 | <<locked>> | 80% | 51,851 psi | 81% | 2812 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 51,953 psi | 81% | 2825 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,439 psi | 68% | 2717 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 39,378 psi | 62% | 2697 fps | 98.8% |
| Vihtavuori N165 | <<locked>> | 90% | 38,421 psi | 60% | 2680 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 50,183 psi | 79% | 2822 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,783 psi | 61% | 2697 fps | 98.5% |
| Vihtavuori N555 | <<locked>> | 80% | 30,110 psi | 47% | 2539 fps | 96.8% |
| Vihtavuori N560 | <<locked>> | 94% | 48,080 psi | 75% | 2979 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,450 psi | 60% | 2664 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 40,234 psi | 63% | 2753 fps | 96.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,105 psi | 38% | 2428 fps | 95.3% |
| Winchester StaBALL Match | <<locked>> | 80% | 53,925 psi | 85% | 2936 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 41,046 psi | 64% | 2743 fps | 95.3% |
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 101 powders for .378 Weath. Mag. loaded with the .375 | 250gr | Speer TBBC. Alliant Reloder-26 delivers the highest muzzle velocity at 3,166 fps; across all powders the maximum-charge window runs from 1,857 fps to 3,166 fps. Accurate 3100 gives the best case fill at 100 %, and 101 of the 101 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 50–90 %, leaving at least 10 % headroom. The 250.0 gr projectile in 0.375" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2213, ADI AR 2217 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, Norma MRP, ReloadSwiss RS 70 rank at the top here: for .378 Weath. Mag. with the .375 | 250gr | Speer TBBC they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2217, Baschieri & Pellagri 109, Bofors RP30 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.