Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 305gr | Hammer Stone Hammer bullet and 79 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N560, Norma MRP 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.
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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 96% | 55,869 psi | 88% | 2736 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 57,653 psi | 90% | 2769 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 54,317 psi | 85% | 2835 fps | 98.4% |
| ADI AR 2208 | <<locked>> | 82% | 55,376 psi | 87% | 2677 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 54,563 psi | 86% | 2772 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 96% | 55,912 psi | 88% | 2835 fps | 99.2% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 46,673 psi | 73% | 2677 fps | 98.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,495 psi | 65% | 2644 fps | 99.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 56,710 psi | 89% | 2697 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 54,795 psi | 86% | 2769 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 55,811 psi | 87% | 2782 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 57,609 psi | 90% | 2815 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 96% | 55,724 psi | 87% | 2828 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 98% | 56,739 psi | 89% | 2792 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 52,301 psi | 82% | 2805 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 57,130 psi | 90% | 2887 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 54,346 psi | 85% | 2740 fps | 96.5% |
| Bofors RP15 | <<locked>> | 98% | 54,723 psi | 86% | 2812 fps | 99.7% |
| Bofors RP3 | <<locked>> | 82% | 57,711 psi | 90% | 2713 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 48,283 psi | 76% | 2746 fps | 98.7% |
| Bofors RP5 | <<locked>> | 96% | 55,724 psi | 87% | 2828 fps | 99.8% |
| Bofors RP7 | <<locked>> | 86% | 56,681 psi | 89% | 2717 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 51,532 psi | 81% | 2762 fps | 99.3% |
| Hodgdon H414 | <<locked>> | 86% | 55,709 psi | 87% | 2769 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 54,868 psi | 86% | 2730 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 94% | 55,898 psi | 88% | 2772 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 94% | 54,897 psi | 86% | 2759 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 55,114 psi | 86% | 2694 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 51,285 psi | 80% | 2871 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 86% | 55,883 psi | 88% | 2808 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,072 psi | 58% | 1683 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 54,592 psi | 86% | 2707 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 84% | 54,607 psi | 86% | 2687 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 54,346 psi | 85% | 2710 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 57,116 psi | 90% | 2756 fps | 99% |
| IMR 7828 SSC | <<locked>> | 98% | 57,435 psi | 90% | 2867 fps | 99.5% |
| Lovex S065 | <<locked>> | 86% | 55,230 psi | 87% | 2687 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 56,768 psi | 89% | 2733 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,374 psi | 84% | 2703 fps | 100% |
| Norma 204 | <<locked>> | 88% | 55,288 psi | 87% | 2759 fps | 99.6% |
| Norma 217ᴾ | <<locked>> | 100% | 37,028 psi | 58% | 2575 fps | 98% |
| Norma MRP | <<locked>> | 94% | 55,463 psi | 87% | 2851 fps | 100% |
| Norma URP | <<locked>> | 88% | 56,086 psi | 88% | 2753 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 54,172 psi | 85% | 2831 fps | 99.4% |
| Ramshot Hunter | <<locked>> | 88% | 54,723 psi | 86% | 2759 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 56,202 psi | 88% | 2822 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,855 psi | 59% | 1722 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 57,479 psi | 90% | 2726 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 55,288 psi | 87% | 2769 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 57,595 psi | 90% | 2792 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 55,825 psi | 87% | 2822 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 51,605 psi | 81% | 2867 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 46,383 psi | 73% | 2753 fps | 97.1% |
| Rottweil R 903 | <<locked>> | 82% | 54,433 psi | 85% | 2667 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 55,883 psi | 88% | 2743 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 94% | 57,246 psi | 90% | 2805 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 86% | 56,681 psi | 89% | 2717 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 86% | 55,230 psi | 87% | 2687 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 56,768 psi | 89% | 2733 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 55,796 psi | 87% | 2723 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 54,534 psi | 85% | 2543 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 54,404 psi | 85% | 2644 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 56,797 psi | 89% | 2802 fps | 99.8% |
| Somchem S355 | <<locked>> | 84% | 57,522 psi | 90% | 2707 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 57,508 psi | 90% | 2740 fps | 98.9% |
| Somchem S365 | <<locked>> | 90% | 56,289 psi | 88% | 2753 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 54,186 psi | 85% | 2726 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 84% | 55,216 psi | 87% | 2631 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 54,273 psi | 85% | 2694 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 57,116 psi | 90% | 2756 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 88% | 57,000 psi | 89% | 2749 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 55,477 psi | 87% | 2769 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 55,361 psi | 87% | 2848 fps | 99% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 54,926 psi | 86% | 2825 fps | 99% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 47,805 psi | 75% | 2762 fps | 96.8% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 57,377 psi | 90% | 2703 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 55,883 psi | 88% | 2772 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 98% | 53,780 psi | 84% | 2877 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 57,725 psi | 90% | 2776 fps | 99.8% |
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% | 32,793 psi | 51% | 2333 fps | 97.7% |
| Accurate 4350 | <<locked>> | 80% | 44,077 psi | 69% | 2566 fps | 100% |
| Accurate MAGPRO | 99.7 gr | 86% | 41,002 psi | 64% | 2598 fps | 95.2% |
| ADI AR 2208 | <<locked>> | 80% | 52,127 psi | 82% | 2628 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,825 psi | 58% | 2448 fps | 96.3% |
| ADI AR 2213 | <<locked>> | 84% | 37,449 psi | 59% | 2490 fps | 95% |
| ADI AR 2217 | <<locked>> | 94% | 38,348 psi | 60% | 2507 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 90% | 30,226 psi | 47% | 2362 fps | 95.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 53,330 psi | 84% | 2651 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 42,235 psi | 66% | 2572 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,515 psi | 76% | 2680 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,825 psi | 58% | 2448 fps | 96.4% |
| Alliant Reloder-22 | <<locked>> | 82% | 34,867 psi | 55% | 2444 fps | 95.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,473 psi | 49% | 2359 fps | 99.8% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,499 psi | 43% | 2274 fps | 96.1% |
| Alliant Reloder-26 | <<locked>> | 80% | 34,011 psi | 53% | 2487 fps | 99.3% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 51,140 psi | 80% | 2687 fps | 95.8% |
| Bofors RP15 | <<locked>> | 84% | 34,650 psi | 54% | 2438 fps | 95.6% |
| Bofors RP3 | <<locked>> | 80% | 54,099 psi | 85% | 2667 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 36,970 psi | 58% | 2526 fps | 95.8% |
| Bofors RP5 | <<locked>> | 82% | 34,867 psi | 55% | 2444 fps | 95.9% |
| Bofors RP7 | <<locked>> | 80% | 47,065 psi | 74% | 2569 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 90% | 36,709 psi | 58% | 2474 fps | 95.7% |
| Hodgdon H414 | <<locked>> | 80% | 45,759 psi | 72% | 2612 fps | 99.5% |
| Hodgdon H4350 | <<locked>> | 80% | 48,298 psi | 76% | 2625 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 84% | 39,958 psi | 63% | 2497 fps | 95.3% |
| Hodgdon H4831 SC | <<locked>> | 84% | 39,233 psi | 61% | 2484 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 39,827 psi | 62% | 2461 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 32,474 psi | 51% | 2454 fps | 95.2% |
| Hodgdon Superformance | <<locked>> | 80% | 44,991 psi | 71% | 2638 fps | 99.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,717 psi | 43% | 1499 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,496 psi | 67% | 2507 fps | 98.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 48,312 psi | 76% | 2589 fps | 99.7% |
| IMR 4831 | <<locked>> | 80% | 41,959 psi | 66% | 2513 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 39,334 psi | 62% | 2448 fps | 95.2% |
| IMR 7828 SSC | <<locked>> | 86% | 38,421 psi | 60% | 2526 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 45,977 psi | 72% | 2543 fps | 99.9% |
| Lovex S070 | <<locked>> | 80% | 44,222 psi | 69% | 2536 fps | 99.4% |
| Lovex S071 | <<locked>> | 80% | 28,224 psi | 44% | 2215 fps | 95.9% |
| Norma 204 | <<locked>> | 80% | 42,279 psi | 66% | 2539 fps | 97.7% |
| Norma 217 | <<locked>> | 94% | 30,545 psi | 48% | 2405 fps | 95.2% |
| Norma MRP | 91.1 gr | 80% | 34,040 psi | 53% | 2454 fps | 97.1% |
| Norma URP | <<locked>> | 80% | 43,279 psi | 68% | 2552 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 38,043 psi | 60% | 2533 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 42,047 psi | 66% | 2552 fps | 99.5% |
| Ramshot Magnum | <<locked>> | 84% | 31,488 psi | 49% | 2359 fps | 95.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,369 psi | 44% | 1539 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 53,882 psi | 84% | 2677 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,488 psi | 81% | 2717 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 43,918 psi | 69% | 2585 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 42,105 psi | 66% | 2602 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 31,560 psi | 49% | 2431 fps | 96.1% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 40,161 psi | 63% | 2628 fps | 95.1% |
| Rottweil R 903 | <<locked>> | 80% | 50,966 psi | 80% | 2618 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 38,174 psi | 60% | 2428 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 80% | 36,042 psi | 56% | 2431 fps | 96.3% |
| Rottweil R 907 | <<locked>> | 80% | 47,065 psi | 74% | 2569 fps | 99.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 45,977 psi | 72% | 2543 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 80% | 44,222 psi | 69% | 2536 fps | 99.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 52,214 psi | 82% | 2674 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 51,271 psi | 80% | 2500 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,976 psi | 70% | 2497 fps | 99.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,723 psi | 56% | 2425 fps | 96.2% |
| Somchem S355 | <<locked>> | 80% | 50,952 psi | 80% | 2615 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 41,437 psi | 65% | 2470 fps | 95.7% |
| Somchem S365 | <<locked>> | 80% | 40,147 psi | 63% | 2513 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,651 psi | 57% | 2415 fps | 97.3% |
| Vihtavuori N150 | <<locked>> | 80% | 48,675 psi | 76% | 2543 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,744 psi | 70% | 2549 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 31,705 psi | 50% | 2297 fps | 95.2% |
| Vihtavuori N550 | <<locked>> | 80% | 44,121 psi | 69% | 2552 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 35,302 psi | 55% | 2431 fps | 99.7% |
| Vihtavuori N560 | 95.6 gr | 84% | 39,305 psi | 62% | 2556 fps | 95.4% |
| Vihtavuori N565 | <<locked>> | 90% | 39,218 psi | 61% | 2549 fps | 95.7% |
| Vihtavuori N568 | <<locked>> | 96% | 41,756 psi | 65% | 2644 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,598 psi | 68% | 2510 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 45,759 psi | 72% | 2612 fps | 99.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,847 psi | 44% | 2375 fps | 99.9% |
| Winchester Supreme 780 | <<locked>> | 80% | 33,388 psi | 52% | 2343 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 84 powders for .378 Weath. Mag. loaded with the .375 | 305gr | Hammer Stone Hammer. Alliant Reloder-26 delivers the highest muzzle velocity at 2,887 fps; across all powders the maximum-charge window runs from 1,683 fps to 2,887 fps. ADI AR 2217 gives the best case fill at 100 %, and 84 of the 84 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 305.0 gr projectile in 0.375" calls for a 1:17.0 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, Norma MRP, Accurate MAGPRO rank at the top here: for .378 Weath. Mag. with the .375 | 305gr | Hammer Stone Hammer they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-33, IMR 7977 Enduron, Vihtavuori N170 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.