Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 300gr | SUS-TAC Solid Flat Nose bullet and 81 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N560, 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.
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 3100 | <<locked>> | 96% | 56,333 psi | 88% | 2766 fps | 100% |
| Accurate 4350 | <<locked>> | 86% | 54,302 psi | 85% | 2746 fps | 100% |
| Accurate High Country | <<locked>> | 92% | 53,969 psi | 85% | 2864 fps | 99.1% |
| Accurate MAGPRO | <<locked>> | 94% | 54,665 psi | 86% | 2864 fps | 98.3% |
| ADI AR 2208 | <<locked>> | 82% | 55,593 psi | 87% | 2703 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 54,940 psi | 86% | 2805 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 96% | 56,188 psi | 88% | 2864 fps | 99.2% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 46,992 psi | 74% | 2707 fps | 98.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,771 psi | 65% | 2671 fps | 99.4% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 55,085 psi | 86% | 2799 fps | 99.6% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 55,085 psi | 86% | 2799 fps | 99.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 56,898 psi | 89% | 2726 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 55,027 psi | 86% | 2799 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 56,202 psi | 88% | 2815 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 92% | 54,389 psi | 85% | 2792 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 96% | 56,014 psi | 88% | 2858 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 98% | 57,043 psi | 89% | 2822 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 52,649 psi | 83% | 2835 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 57,696 psi | 90% | 2920 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 54,737 psi | 86% | 2772 fps | 96.5% |
| Bofors RP15 | <<locked>> | 98% | 54,984 psi | 86% | 2841 fps | 99.7% |
| Bofors RP30ᴾ | <<locked>> | 100% | 48,646 psi | 76% | 2776 fps | 98.7% |
| Bofors RP5 | <<locked>> | 96% | 56,014 psi | 88% | 2858 fps | 99.8% |
| Bofors RP7 | <<locked>> | 86% | 56,927 psi | 89% | 2749 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 51,793 psi | 81% | 2789 fps | 99.3% |
| Hodgdon H414 | <<locked>> | 86% | 56,043 psi | 88% | 2802 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 55,259 psi | 87% | 2759 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 94% | 56,362 psi | 88% | 2802 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 94% | 55,172 psi | 86% | 2785 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 55,303 psi | 87% | 2720 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 51,576 psi | 81% | 2900 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 86% | 56,188 psi | 88% | 2838 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,970 psi | 58% | 1699 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 54,926 psi | 86% | 2736 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 84% | 54,868 psi | 86% | 2720 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 54,520 psi | 85% | 2740 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 57,450 psi | 90% | 2785 fps | 99% |
| IMR 7828 SSC | <<locked>> | 96% | 53,940 psi | 85% | 2841 fps | 99% |
| Lovex S065 | <<locked>> | 86% | 55,477 psi | 87% | 2717 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 56,956 psi | 89% | 2762 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,693 psi | 84% | 2730 fps | 100% |
| Norma 204 | <<locked>> | 88% | 55,724 psi | 87% | 2789 fps | 99.6% |
| Norma 217ᴾ | <<locked>> | 100% | 37,289 psi | 58% | 2602 fps | 97.9% |
| Norma MRP | <<locked>> | 94% | 55,854 psi | 88% | 2881 fps | 100% |
| Norma URP | <<locked>> | 88% | 56,275 psi | 88% | 2782 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 54,607 psi | 86% | 2861 fps | 99.4% |
| Ramshot Hunter | <<locked>> | 88% | 55,129 psi | 86% | 2789 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 56,768 psi | 89% | 2854 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,869 psi | 59% | 1742 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 57,725 psi | 90% | 2756 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 55,753 psi | 87% | 2799 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 54,085 psi | 85% | 2769 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 56,202 psi | 88% | 2854 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 52,011 psi | 82% | 2897 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 46,818 psi | 73% | 2782 fps | 97% |
| Rottweil R 903 | <<locked>> | 82% | 54,636 psi | 86% | 2694 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 56,275 psi | 88% | 2772 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 94% | 57,624 psi | 90% | 2835 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 86% | 56,927 psi | 89% | 2749 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 86% | 55,477 psi | 87% | 2717 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 56,956 psi | 89% | 2762 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 56,101 psi | 88% | 2753 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 54,824 psi | 86% | 2572 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 54,737 psi | 86% | 2674 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 57,174 psi | 90% | 2831 fps | 99.8% |
| Somchem S355 | <<locked>> | 82% | 54,360 psi | 85% | 2687 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 54,128 psi | 85% | 2713 fps | 98.4% |
| Somchem S365 | <<locked>> | 90% | 56,608 psi | 89% | 2782 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 54,389 psi | 85% | 2756 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 84% | 55,506 psi | 87% | 2661 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 54,650 psi | 86% | 2723 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 57,464 psi | 90% | 2785 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 88% | 57,290 psi | 90% | 2779 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 55,869 psi | 88% | 2802 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 55,782 psi | 87% | 2877 fps | 98.9% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 55,245 psi | 87% | 2854 fps | 99% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 48,341 psi | 76% | 2792 fps | 96.8% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 57,682 psi | 90% | 2733 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 56,188 psi | 88% | 2805 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 98% | 54,201 psi | 85% | 2907 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 54,201 psi | 85% | 2749 fps | 99.6% |
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% | 32,953 psi | 52% | 2356 fps | 97.6% |
| Accurate 4350 | <<locked>> | 80% | 44,295 psi | 69% | 2592 fps | 100% |
| Accurate High Country | 95.1 gr | 82% | 38,145 psi | 60% | 2569 fps | 95.7% |
| Accurate MAGPRO | 101.6 gr | 86% | 41,336 psi | 65% | 2625 fps | 95.2% |
| ADI AR 2208 | <<locked>> | 80% | 52,402 psi | 82% | 2657 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,999 psi | 58% | 2474 fps | 96.2% |
| ADI AR 2213 | <<locked>> | 84% | 37,739 psi | 59% | 2516 fps | 95% |
| ADI AR 2217 | <<locked>> | 94% | 38,595 psi | 60% | 2536 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 90% | 30,371 psi | 48% | 2385 fps | 95.4% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 37,333 psi | 59% | 2477 fps | 96.4% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 37,333 psi | 59% | 2477 fps | 96.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 53,447 psi | 84% | 2677 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 42,511 psi | 67% | 2598 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,805 psi | 76% | 2710 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,999 psi | 58% | 2470 fps | 96.3% |
| Alliant Reloder-22 | <<locked>> | 82% | 35,114 psi | 55% | 2470 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,647 psi | 50% | 2385 fps | 99.8% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,630 psi | 43% | 2297 fps | 96% |
| Alliant Reloder-26 | <<locked>> | 80% | 34,316 psi | 54% | 2513 fps | 99.2% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 51,401 psi | 81% | 2713 fps | 95.7% |
| Bofors RP15 | <<locked>> | 84% | 34,882 psi | 55% | 2464 fps | 95.6% |
| Bofors RP30 | <<locked>> | 92% | 37,159 psi | 58% | 2549 fps | 95.8% |
| Bofors RP5 | <<locked>> | 82% | 35,114 psi | 55% | 2470 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 47,166 psi | 74% | 2592 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 90% | 37,028 psi | 58% | 2503 fps | 95.7% |
| Hodgdon H414 | <<locked>> | 80% | 45,905 psi | 72% | 2638 fps | 99.5% |
| Hodgdon H4350 | <<locked>> | 80% | 48,602 psi | 76% | 2651 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 84% | 40,248 psi | 63% | 2523 fps | 95.2% |
| Hodgdon H4831 SC | <<locked>> | 84% | 39,566 psi | 62% | 2510 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 40,074 psi | 63% | 2487 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 32,735 psi | 51% | 2480 fps | 95.2% |
| Hodgdon Superformance | <<locked>> | 80% | 45,237 psi | 71% | 2664 fps | 99.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,789 psi | 44% | 1519 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,699 psi | 67% | 2530 fps | 98.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 48,515 psi | 76% | 2618 fps | 99.6% |
| IMR 4831 | <<locked>> | 80% | 42,163 psi | 66% | 2539 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 39,479 psi | 62% | 2470 fps | 95.2% |
| IMR 7828 SSC | <<locked>> | 86% | 38,725 psi | 61% | 2552 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 46,209 psi | 72% | 2572 fps | 99.9% |
| Lovex S070 | <<locked>> | 80% | 44,425 psi | 70% | 2562 fps | 99.4% |
| Lovex S071 | <<locked>> | 80% | 28,456 psi | 45% | 2241 fps | 95.9% |
| Norma 204 | <<locked>> | 80% | 42,554 psi | 67% | 2566 fps | 97.7% |
| Norma 217 | <<locked>> | 94% | 30,792 psi | 48% | 2431 fps | 95.2% |
| Norma MRP | <<locked>> | 80% | 34,272 psi | 54% | 2480 fps | 97% |
| Norma URP | <<locked>> | 80% | 43,482 psi | 68% | 2579 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 38,261 psi | 60% | 2559 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 42,308 psi | 66% | 2579 fps | 99.5% |
| Ramshot Magnum | <<locked>> | 84% | 31,705 psi | 50% | 2385 fps | 95.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,311 psi | 44% | 1555 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 54,157 psi | 85% | 2703 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,822 psi | 81% | 2746 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 44,063 psi | 69% | 2612 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 42,366 psi | 66% | 2628 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 31,720 psi | 50% | 2457 fps | 96.1% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 40,480 psi | 63% | 2654 fps | 95.1% |
| Rottweil R 903 | <<locked>> | 80% | 51,213 psi | 80% | 2644 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 38,377 psi | 60% | 2454 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 80% | 36,230 psi | 57% | 2454 fps | 96.3% |
| Rottweil R 907 | <<locked>> | 80% | 47,166 psi | 74% | 2592 fps | 99.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 46,209 psi | 72% | 2572 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 80% | 44,425 psi | 70% | 2562 fps | 99.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 52,533 psi | 82% | 2703 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 51,576 psi | 81% | 2530 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 45,136 psi | 71% | 2520 fps | 99.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,955 psi | 56% | 2451 fps | 96.1% |
| Somchem S355 | <<locked>> | 80% | 51,198 psi | 80% | 2644 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 41,713 psi | 65% | 2500 fps | 95.7% |
| Somchem S365 | <<locked>> | 80% | 40,379 psi | 63% | 2539 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,912 psi | 58% | 2441 fps | 97.3% |
| Vihtavuori N150 | <<locked>> | 80% | 48,907 psi | 77% | 2569 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,933 psi | 70% | 2572 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 31,894 psi | 50% | 2323 fps | 95.1% |
| Vihtavuori N550 | <<locked>> | 80% | 44,266 psi | 69% | 2579 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 35,549 psi | 56% | 2457 fps | 99.7% |
| Vihtavuori N560 | 97.4 gr | 84% | 39,610 psi | 62% | 2585 fps | 95.3% |
| Vihtavuori N565 | <<locked>> | 90% | 39,436 psi | 62% | 2572 fps | 95.6% |
| Vihtavuori N568 | <<locked>> | 98% | 44,976 psi | 70% | 2730 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,932 psi | 69% | 2539 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 46,021 psi | 72% | 2641 fps | 99.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 28,050 psi | 44% | 2402 fps | 99.9% |
| Winchester Supreme 780 | <<locked>> | 80% | 33,518 psi | 53% | 2365 fps | 95% |
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 81 powders for .378 Weath. Mag. loaded with the .375 | 300gr | SUS-TAC Solid Flat Nose. Alliant Reloder-26 delivers the highest muzzle velocity at 2,920 fps; across all powders the maximum-charge window runs from 1,699 fps to 2,920 fps. ADI AR 2217 gives the best case fill at 100 %, and 81 of the 81 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 300.0 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. Vihtavuori N560, Accurate MAGPRO, Accurate High Country rank at the top here: for .378 Weath. Mag. with the .375 | 300gr | SUS-TAC Solid Flat Nose 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.