Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 305gr | Hammer Claw Hammer bullet and 78 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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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% | 55,912 psi | 88% | 2736 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 57,725 psi | 90% | 2766 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 54,360 psi | 85% | 2831 fps | 98.4% |
| ADI AR 2208 | <<locked>> | 82% | 55,419 psi | 87% | 2674 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 54,607 psi | 86% | 2772 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 96% | 55,840 psi | 88% | 2831 fps | 99.2% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 46,746 psi | 73% | 2677 fps | 98.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,437 psi | 65% | 2641 fps | 99.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 56,724 psi | 89% | 2697 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 54,650 psi | 86% | 2766 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 55,898 psi | 88% | 2782 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 57,682 psi | 90% | 2815 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 96% | 55,593 psi | 87% | 2825 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 98% | 56,594 psi | 89% | 2792 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 52,170 psi | 82% | 2802 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 57,174 psi | 90% | 2887 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 54,447 psi | 85% | 2740 fps | 96.5% |
| Bofors RP15 | <<locked>> | 98% | 54,621 psi | 86% | 2812 fps | 99.7% |
| Bofors RP30ᴾ | <<locked>> | 100% | 48,182 psi | 76% | 2746 fps | 98.7% |
| Bofors RP5 | <<locked>> | 96% | 55,593 psi | 87% | 2825 fps | 99.8% |
| Bofors RP7 | <<locked>> | 86% | 56,536 psi | 89% | 2717 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 51,401 psi | 81% | 2759 fps | 99.3% |
| Hodgdon H414 | <<locked>> | 86% | 55,593 psi | 87% | 2769 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 54,897 psi | 86% | 2730 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 94% | 55,970 psi | 88% | 2772 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 94% | 54,781 psi | 86% | 2756 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 54,998 psi | 86% | 2694 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 51,184 psi | 80% | 2867 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 86% | 55,956 psi | 88% | 2808 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,956 psi | 58% | 1680 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 54,505 psi | 85% | 2703 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 84% | 54,665 psi | 86% | 2687 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 54,230 psi | 85% | 2707 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 57,000 psi | 89% | 2753 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 98% | 57,319 psi | 90% | 2864 fps | 99.4% |
| Lovex S065 | <<locked>> | 86% | 55,129 psi | 86% | 2684 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 56,681 psi | 89% | 2733 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,214 psi | 83% | 2700 fps | 100% |
| Norma 204 | <<locked>> | 88% | 55,361 psi | 87% | 2759 fps | 99.6% |
| Norma 217ᴾ | <<locked>> | 100% | 37,028 psi | 58% | 2572 fps | 98% |
| Norma MRP | <<locked>> | 94% | 55,506 psi | 87% | 2851 fps | 100% |
| Norma URP | <<locked>> | 88% | 55,941 psi | 88% | 2749 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 54,099 psi | 85% | 2828 fps | 99.3% |
| Ramshot Hunter | <<locked>> | 88% | 54,766 psi | 86% | 2759 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 56,260 psi | 88% | 2822 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,884 psi | 59% | 1722 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 57,363 psi | 90% | 2723 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 55,376 psi | 87% | 2766 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 57,435 psi | 90% | 2789 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 55,709 psi | 87% | 2822 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 51,503 psi | 81% | 2864 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 46,470 psi | 73% | 2753 fps | 97% |
| Rottweil R 903 | <<locked>> | 82% | 54,302 psi | 85% | 2664 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 55,970 psi | 88% | 2743 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 94% | 57,159 psi | 90% | 2802 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 86% | 56,536 psi | 89% | 2717 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 86% | 55,129 psi | 86% | 2684 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 56,681 psi | 89% | 2733 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 55,695 psi | 87% | 2720 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 54,607 psi | 86% | 2543 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 54,476 psi | 85% | 2644 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 56,710 psi | 89% | 2799 fps | 99.8% |
| Somchem S355 | <<locked>> | 84% | 57,580 psi | 90% | 2703 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 57,580 psi | 90% | 2736 fps | 98.9% |
| Somchem S365 | <<locked>> | 90% | 56,159 psi | 88% | 2749 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 57,682 psi | 90% | 2776 fps | 100% |
| Vihtavuori N150 | <<locked>> | 84% | 55,274 psi | 87% | 2631 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 54,317 psi | 85% | 2694 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 57,159 psi | 90% | 2756 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 88% | 56,884 psi | 89% | 2746 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 55,506 psi | 87% | 2769 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 55,434 psi | 87% | 2844 fps | 98.9% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 54,853 psi | 86% | 2825 fps | 99% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 47,877 psi | 75% | 2759 fps | 96.8% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 57,406 psi | 90% | 2700 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 55,767 psi | 87% | 2772 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 98% | 53,621 psi | 84% | 2874 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 53,824 psi | 84% | 2720 fps | 99.5% |
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% | 32,692 psi | 51% | 2329 fps | 97.7% |
| Accurate 4350 | <<locked>> | 80% | 43,976 psi | 69% | 2562 fps | 100% |
| Accurate MAGPRO | 99.7 gr | 86% | 41,031 psi | 64% | 2595 fps | 95.2% |
| ADI AR 2208 | <<locked>> | 80% | 52,141 psi | 82% | 2628 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,854 psi | 58% | 2448 fps | 96.3% |
| ADI AR 2213 | <<locked>> | 84% | 37,492 psi | 59% | 2490 fps | 95% |
| ADI AR 2217 | <<locked>> | 94% | 38,406 psi | 60% | 2510 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 90% | 30,269 psi | 47% | 2362 fps | 95.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 53,214 psi | 83% | 2648 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 42,264 psi | 66% | 2572 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,559 psi | 76% | 2680 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,753 psi | 58% | 2444 fps | 96.3% |
| Alliant Reloder-22 | <<locked>> | 82% | 34,911 psi | 55% | 2444 fps | 95.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,386 psi | 49% | 2356 fps | 99.8% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,514 psi | 43% | 2270 fps | 96.1% |
| Alliant Reloder-26 | <<locked>> | 80% | 34,026 psi | 53% | 2484 fps | 99.2% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 51,198 psi | 80% | 2687 fps | 95.8% |
| Bofors RP15 | <<locked>> | 84% | 34,693 psi | 54% | 2438 fps | 95.6% |
| Bofors RP30 | <<locked>> | 92% | 36,883 psi | 58% | 2523 fps | 95.8% |
| Bofors RP5 | <<locked>> | 82% | 34,911 psi | 55% | 2444 fps | 95.9% |
| Bofors RP7 | <<locked>> | 80% | 46,963 psi | 74% | 2566 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 90% | 36,767 psi | 58% | 2474 fps | 95.7% |
| Hodgdon H414 | <<locked>> | 80% | 45,643 psi | 72% | 2612 fps | 99.5% |
| Hodgdon H4350 | <<locked>> | 80% | 48,370 psi | 76% | 2621 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 84% | 40,001 psi | 63% | 2497 fps | 95.3% |
| Hodgdon H4831 SC | <<locked>> | 84% | 39,262 psi | 62% | 2480 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 39,856 psi | 62% | 2461 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 32,518 psi | 51% | 2454 fps | 95.2% |
| Hodgdon Superformance | <<locked>> | 80% | 44,860 psi | 70% | 2631 fps | 99.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,731 psi | 43% | 1499 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,554 psi | 67% | 2503 fps | 98.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 48,370 psi | 76% | 2589 fps | 99.7% |
| IMR 4831 | <<locked>> | 80% | 42,003 psi | 66% | 2516 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 39,262 psi | 62% | 2444 fps | 95.2% |
| IMR 7828 SSC | <<locked>> | 86% | 38,479 psi | 60% | 2526 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 45,890 psi | 72% | 2543 fps | 99.9% |
| Lovex S070 | <<locked>> | 80% | 44,266 psi | 69% | 2533 fps | 99.4% |
| Lovex S071 | <<locked>> | 80% | 28,268 psi | 44% | 2215 fps | 95.9% |
| Norma 204 | <<locked>> | 80% | 42,322 psi | 66% | 2539 fps | 97.7% |
| Norma 217 | <<locked>> | 94% | 30,487 psi | 48% | 2402 fps | 95.2% |
| Norma MRP | 91 gr | 80% | 33,953 psi | 53% | 2451 fps | 97% |
| Norma URP | <<locked>> | 80% | 43,323 psi | 68% | 2552 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 37,956 psi | 59% | 2530 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 42,090 psi | 66% | 2549 fps | 99.5% |
| Ramshot Magnum | <<locked>> | 84% | 31,531 psi | 49% | 2359 fps | 95.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,384 psi | 44% | 1539 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 53,766 psi | 84% | 2674 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,517 psi | 81% | 2717 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 43,816 psi | 69% | 2585 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 42,032 psi | 66% | 2598 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 31,502 psi | 49% | 2428 fps | 96.1% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 40,176 psi | 63% | 2628 fps | 95.1% |
| Rottweil R 903 | <<locked>> | 80% | 51,024 psi | 80% | 2618 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 38,218 psi | 60% | 2428 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 80% | 36,085 psi | 57% | 2428 fps | 96.3% |
| Rottweil R 907 | <<locked>> | 80% | 46,963 psi | 74% | 2566 fps | 99.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 45,890 psi | 72% | 2543 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 80% | 44,266 psi | 69% | 2533 fps | 99.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 52,257 psi | 82% | 2671 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 51,285 psi | 80% | 2500 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,875 psi | 70% | 2493 fps | 99.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,752 psi | 56% | 2425 fps | 96.2% |
| Somchem S355 | <<locked>> | 80% | 50,865 psi | 80% | 2612 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 41,336 psi | 65% | 2470 fps | 95.6% |
| Somchem S365 | <<locked>> | 80% | 40,176 psi | 63% | 2513 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,651 psi | 57% | 2415 fps | 97.3% |
| Vihtavuori N150 | <<locked>> | 80% | 48,704 psi | 76% | 2543 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,657 psi | 70% | 2546 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 31,633 psi | 50% | 2293 fps | 95.1% |
| Vihtavuori N550 | <<locked>> | 80% | 44,019 psi | 69% | 2549 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 35,201 psi | 55% | 2425 fps | 99.7% |
| Vihtavuori N560 | 95.6 gr | 84% | 39,363 psi | 62% | 2556 fps | 95.4% |
| Vihtavuori N565 | <<locked>> | 90% | 39,146 psi | 61% | 2546 fps | 95.7% |
| Vihtavuori N568 | <<locked>> | 98% | 44,672 psi | 70% | 2700 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,642 psi | 68% | 2510 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 45,774 psi | 72% | 2612 fps | 99.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,876 psi | 44% | 2375 fps | 99.9% |
| Winchester Supreme 780 | <<locked>> | 80% | 33,315 psi | 52% | 2339 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 83 powders for .378 Weath. Mag. loaded with the .375 | 305gr | Hammer Claw Hammer . Alliant Reloder-26 delivers the highest muzzle velocity at 2,887 fps; across all powders the maximum-charge window runs from 1,680 fps to 2,887 fps. ADI AR 2217 gives the best case fill at 100 %, and 83 of the 83 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 1:6.0 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, Norma MRP, Accurate MAGPRO rank at the top here: for .378 Weath. Mag. with the .375 | 305gr | Hammer Claw 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.