Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 300gr | Hornady BTSP bullet and 82 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% | 54,969 psi | 86% | 2746 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 56,768 psi | 89% | 2776 fps | 100% |
| Accurate MAGPRO | <<locked>> | 96% | 57,232 psi | 90% | 2897 fps | 98.6% |
| ADI AR 2208 | <<locked>> | 82% | 54,708 psi | 86% | 2687 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 57,261 psi | 90% | 2831 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 96% | 54,955 psi | 86% | 2838 fps | 99% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 45,876 psi | 72% | 2677 fps | 97.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 40,741 psi | 64% | 2644 fps | 99.2% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 57,551 psi | 90% | 2828 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 55,912 psi | 88% | 2707 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 57,479 psi | 90% | 2828 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 54,955 psi | 86% | 2792 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 56,811 psi | 89% | 2822 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 96% | 54,650 psi | 86% | 2835 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 98% | 55,593 psi | 87% | 2802 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 51,256 psi | 80% | 2808 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 56,057 psi | 88% | 2894 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 57,014 psi | 89% | 2799 fps | 96.8% |
| Bofors RP15ᴾ | <<locked>> | 100% | 57,145 psi | 90% | 2867 fps | 99.8% |
| Bofors RP3 | <<locked>> | 82% | 56,884 psi | 89% | 2723 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 47,239 psi | 74% | 2749 fps | 98.4% |
| Bofors RP5 | <<locked>> | 96% | 54,650 psi | 86% | 2835 fps | 99.7% |
| Bofors RP7 | <<locked>> | 86% | 55,970 psi | 88% | 2726 fps | 99.9% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 50,589 psi | 79% | 2762 fps | 99% |
| Hodgdon H380 | <<locked>> | 82% | 57,014 psi | 89% | 2746 fps | 100% |
| Hodgdon H414 | <<locked>> | 86% | 54,737 psi | 86% | 2779 fps | 100% |
| Hodgdon H4350 | <<locked>> | 86% | 57,682 psi | 90% | 2789 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 94% | 55,100 psi | 86% | 2779 fps | 98.5% |
| Hodgdon H4831 SC | <<locked>> | 96% | 57,638 psi | 90% | 2815 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 54,099 psi | 85% | 2700 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 50,256 psi | 79% | 2871 fps | 99.8% |
| Hodgdon Superformance | <<locked>> | 86% | 55,027 psi | 86% | 2818 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,999 psi | 58% | 1693 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 57,609 psi | 90% | 2713 fps | 100% |
| IMR 4350 | <<locked>> | 90% | 57,188 psi | 90% | 2762 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 86% | 57,421 psi | 90% | 2749 fps | 100% |
| IMR 4831 | <<locked>> | 90% | 56,971 psi | 89% | 2766 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 56,217 psi | 88% | 2762 fps | 98.7% |
| IMR 7828 SSC | <<locked>> | 98% | 56,347 psi | 88% | 2871 fps | 99.2% |
| Lovex S065 | <<locked>> | 86% | 54,520 psi | 85% | 2697 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 55,869 psi | 88% | 2743 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 52,301 psi | 82% | 2707 fps | 100% |
| Norma 204 | <<locked>> | 88% | 54,549 psi | 85% | 2769 fps | 99.4% |
| Norma 217ᴾ | <<locked>> | 100% | 36,318 psi | 57% | 2572 fps | 97.5% |
| Norma MRP | <<locked>> | 94% | 54,317 psi | 85% | 2854 fps | 100% |
| Norma URP | <<locked>> | 88% | 55,114 psi | 86% | 2759 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 57,203 psi | 90% | 2894 fps | 99.5% |
| Ramshot Hunter | <<locked>> | 90% | 57,464 psi | 90% | 2818 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 55,230 psi | 87% | 2828 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,768 psi | 59% | 1732 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 56,637 psi | 89% | 2736 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 54,360 psi | 85% | 2779 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 56,521 psi | 89% | 2802 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 54,766 psi | 86% | 2828 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 50,560 psi | 79% | 2871 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 45,455 psi | 71% | 2753 fps | 96.5% |
| Rottweil R 903 | <<locked>> | 84% | 57,101 psi | 89% | 2723 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 55,158 psi | 86% | 2749 fps | 99% |
| Rottweil R 905 | <<locked>> | 94% | 56,246 psi | 88% | 2812 fps | 99.7% |
| Rottweil R 907 | <<locked>> | 86% | 55,970 psi | 88% | 2726 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 86% | 54,520 psi | 85% | 2697 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 55,869 psi | 88% | 2743 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 54,897 psi | 86% | 2733 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 57,159 psi | 90% | 2595 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 57,319 psi | 90% | 2703 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 55,782 psi | 87% | 2805 fps | 99.7% |
| Somchem S355 | <<locked>> | 84% | 56,782 psi | 89% | 2717 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 56,594 psi | 89% | 2743 fps | 98.6% |
| Somchem S365 | <<locked>> | 90% | 55,172 psi | 86% | 2762 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 56,782 psi | 89% | 2785 fps | 100% |
| Vihtavuori N150 | <<locked>> | 84% | 54,491 psi | 85% | 2644 fps | 100% |
| Vihtavuori N160 | <<locked>> | 88% | 57,116 psi | 90% | 2753 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 56,086 psi | 88% | 2762 fps | 99.8% |
| Vihtavuori N550 | <<locked>> | 88% | 56,043 psi | 88% | 2759 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 54,549 psi | 85% | 2779 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 54,331 psi | 85% | 2851 fps | 98.7% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 53,882 psi | 84% | 2828 fps | 98.8% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 46,818 psi | 73% | 2759 fps | 96.3% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 56,550 psi | 89% | 2713 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 54,926 psi | 86% | 2779 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 56,637 psi | 89% | 2936 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 56,869 psi | 89% | 2782 fps | 99.7% |
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% | 32,169 psi | 50% | 2333 fps | 97.3% |
| Accurate 4350 | <<locked>> | 80% | 43,337 psi | 68% | 2572 fps | 100% |
| Accurate MAGPRO | 101.8 gr | 88% | 43,192 psi | 68% | 2657 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 80% | 51,474 psi | 81% | 2638 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,274 psi | 57% | 2451 fps | 95.8% |
| ADI AR 2213 | <<locked>> | 86% | 39,378 psi | 62% | 2549 fps | 95.5% |
| ADI AR 2217 | <<locked>> | 94% | 37,782 psi | 59% | 2510 fps | 95% |
| ADI AR 2225 | <<locked>> | 92% | 31,676 psi | 50% | 2418 fps | 96% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 36,564 psi | 57% | 2457 fps | 96% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 52,489 psi | 82% | 2661 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 41,582 psi | 65% | 2579 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 47,688 psi | 75% | 2687 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,230 psi | 57% | 2451 fps | 96% |
| Alliant Reloder-22 | <<locked>> | 82% | 34,272 psi | 54% | 2448 fps | 95.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 30,893 psi | 48% | 2362 fps | 99.6% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,064 psi | 42% | 2274 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 33,388 psi | 52% | 2490 fps | 99% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 50,560 psi | 79% | 2694 fps | 95.4% |
| Bofors RP15 | <<locked>> | 84% | 34,055 psi | 53% | 2441 fps | 95.1% |
| Bofors RP3 | <<locked>> | 80% | 53,301 psi | 84% | 2677 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 36,172 psi | 57% | 2526 fps | 95.3% |
| Bofors RP5 | <<locked>> | 82% | 34,272 psi | 54% | 2448 fps | 95.4% |
| Bofors RP7 | <<locked>> | 80% | 46,470 psi | 73% | 2575 fps | 99.1% |
| Hodgdon H1000 | <<locked>> | 90% | 36,158 psi | 57% | 2477 fps | 95.1% |
| Hodgdon H380 | <<locked>> | 80% | 53,476 psi | 84% | 2697 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 44,947 psi | 70% | 2618 fps | 99.3% |
| Hodgdon H4350 | <<locked>> | 80% | 47,645 psi | 75% | 2631 fps | 98.9% |
| Hodgdon H4831 | <<locked>> | 86% | 42,047 psi | 66% | 2556 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 41,307 psi | 65% | 2539 fps | 95.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 39,175 psi | 61% | 2467 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 34,069 psi | 53% | 2513 fps | 95.7% |
| Hodgdon Superformance | <<locked>> | 80% | 44,092 psi | 69% | 2641 fps | 99.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,630 psi | 43% | 1509 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 54,201 psi | 85% | 2667 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 41,916 psi | 66% | 2513 fps | 98.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 47,703 psi | 75% | 2598 fps | 99.5% |
| IMR 4831 | <<locked>> | 80% | 41,292 psi | 65% | 2523 fps | 99.9% |
| IMR 4955 Enduron | <<locked>> | 84% | 41,234 psi | 65% | 2503 fps | 95.6% |
| IMR 7828 SSC | <<locked>> | 86% | 37,826 psi | 59% | 2526 fps | 95% |
| Lovex S065 | <<locked>> | 80% | 45,368 psi | 71% | 2552 fps | 99.8% |
| Lovex S070 | <<locked>> | 80% | 43,584 psi | 68% | 2543 fps | 99.2% |
| Lovex S071 | <<locked>> | 80% | 27,702 psi | 43% | 2218 fps | 95.4% |
| Norma 204 | <<locked>> | 80% | 41,655 psi | 65% | 2546 fps | 97.3% |
| Norma 217 | <<locked>> | 96% | 31,908 psi | 50% | 2461 fps | 95.6% |
| Norma MRP | 90.8 gr | 80% | 33,344 psi | 52% | 2454 fps | 96.6% |
| Norma URP | <<locked>> | 80% | 42,583 psi | 67% | 2559 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 37,275 psi | 58% | 2530 fps | 95.2% |
| Ramshot Hunter | <<locked>> | 80% | 41,379 psi | 65% | 2559 fps | 99.3% |
| Ramshot Magnum | <<locked>> | 86% | 33,214 psi | 52% | 2418 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,268 psi | 44% | 1549 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 53,156 psi | 83% | 2684 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 50,575 psi | 79% | 2726 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 43,033 psi | 67% | 2592 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 41,321 psi | 65% | 2605 fps | 99.9% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 30,966 psi | 49% | 2428 fps | 95.4% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 42,308 psi | 66% | 2690 fps | 95.6% |
| Rottweil R 903 | <<locked>> | 80% | 50,241 psi | 79% | 2628 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 37,623 psi | 59% | 2434 fps | 95.1% |
| Rottweil R 905 | <<locked>> | 80% | 35,447 psi | 56% | 2434 fps | 95.9% |
| Rottweil R 907 | <<locked>> | 80% | 46,470 psi | 73% | 2575 fps | 99.1% |
| Shooters World Long Rifle | <<locked>> | 80% | 45,368 psi | 71% | 2552 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 80% | 43,584 psi | 68% | 2543 fps | 99.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 51,488 psi | 81% | 2684 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 50,633 psi | 79% | 2513 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,280 psi | 69% | 2500 fps | 99.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,114 psi | 55% | 2428 fps | 95.7% |
| Somchem S355 | <<locked>> | 80% | 50,256 psi | 79% | 2625 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 40,872 psi | 64% | 2477 fps | 95.2% |
| Somchem S365 | <<locked>> | 80% | 39,421 psi | 62% | 2520 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,027 psi | 56% | 2421 fps | 96.9% |
| Vihtavuori N150 | <<locked>> | 80% | 48,022 psi | 75% | 2552 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,077 psi | 69% | 2556 fps | 100% |
| Vihtavuori N165 | <<locked>> | 82% | 33,228 psi | 52% | 2352 fps | 95.5% |
| Vihtavuori N550 | <<locked>> | 80% | 43,439 psi | 68% | 2559 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 34,664 psi | 54% | 2434 fps | 99.5% |
| Vihtavuori N560 | 97.7 gr | 86% | 41,423 psi | 65% | 2618 fps | 95.8% |
| Vihtavuori N565 | <<locked>> | 90% | 38,392 psi | 60% | 2549 fps | 95.2% |
| Vihtavuori N568 | <<locked>> | 98% | 43,801 psi | 69% | 2703 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 42,960 psi | 67% | 2520 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 45,078 psi | 71% | 2618 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,340 psi | 43% | 2375 fps | 99.7% |
| Winchester Supreme 780 | <<locked>> | 82% | 35,128 psi | 55% | 2402 fps | 95.5% |
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 82 powders for .378 Weath. Mag. loaded with the .375 | 300gr | Hornady BTSP. Winchester StaBALL HD delivers the highest muzzle velocity at 2,936 fps; across all powders the maximum-charge window runs from 1,693 fps to 2,936 fps. ADI AR 2217 gives the best case fill at 100 %, and 82 of the 82 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 57–90 %, 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, Norma MRP, Accurate MAGPRO rank at the top here: for .378 Weath. Mag. with the .375 | 300gr | Hornady BTSP 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.