Load Specifications
Load data in caliber .378 Weath. Mag. with .375 | 300gr | Reichenberg Super Penetra bullet and 89 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate High Country, Alliant Reloder-26 and Vihtavuori N560.
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 2700 | <<locked>> | 82% | 57,479 psi | 90% | 2717 fps | 99.9% |
| Accurate 3100 | <<locked>> | 98% | 56,855 psi | 89% | 2776 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 57,000 psi | 89% | 2680 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 54,984 psi | 86% | 2759 fps | 100% |
| Accurate High Country | <<locked>> | 94% | 54,665 psi | 86% | 2874 fps | 99.1% |
| Accurate MAGPRO | <<locked>> | 96% | 55,550 psi | 87% | 2874 fps | 98.4% |
| ADI AR 2208 | <<locked>> | 84% | 57,072 psi | 89% | 2723 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 55,970 psi | 88% | 2815 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 98% | 57,464 psi | 90% | 2877 fps | 99.3% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 44,556 psi | 70% | 2657 fps | 97.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 39,378 psi | 62% | 2621 fps | 98.9% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 56,231 psi | 88% | 2815 fps | 99.7% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 56,231 psi | 88% | 2815 fps | 99.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 54,578 psi | 86% | 2694 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 56,144 psi | 88% | 2812 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 57,464 psi | 90% | 2828 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 55,448 psi | 87% | 2805 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 98% | 56,913 psi | 89% | 2871 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 98% | 54,085 psi | 85% | 2785 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 49,850 psi | 78% | 2789 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 54,157 psi | 85% | 2874 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 55,956 psi | 88% | 2785 fps | 96.6% |
| Bofors RP15ᴾ | <<locked>> | 100% | 55,724 psi | 87% | 2851 fps | 99.7% |
| Bofors RP3 | <<locked>> | 82% | 55,288 psi | 87% | 2710 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 45,701 psi | 72% | 2726 fps | 98.1% |
| Bofors RP5 | <<locked>> | 98% | 56,913 psi | 89% | 2871 fps | 99.8% |
| Bofors RP7 | <<locked>> | 86% | 54,621 psi | 86% | 2710 fps | 99.8% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 49,240 psi | 77% | 2746 fps | 98.8% |
| Hodgdon H380 | <<locked>> | 82% | 55,550 psi | 87% | 2733 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 57,174 psi | 90% | 2818 fps | 100% |
| Hodgdon H4350 | <<locked>> | 86% | 56,420 psi | 88% | 2772 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 96% | 57,566 psi | 90% | 2818 fps | 98.8% |
| Hodgdon H4831 SC | <<locked>> | 96% | 56,333 psi | 88% | 2802 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 56,376 psi | 88% | 2736 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 48,834 psi | 77% | 2851 fps | 99.7% |
| Hodgdon Superformance | <<locked>> | 86% | 53,621 psi | 84% | 2799 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,811 psi | 58% | 1690 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 56,521 psi | 89% | 2703 fps | 100% |
| IMR 4350 | <<locked>> | 90% | 55,999 psi | 88% | 2749 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 86% | 56,246 psi | 88% | 2736 fps | 100% |
| IMR 4831 | <<locked>> | 90% | 55,419 psi | 87% | 2749 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 55,027 psi | 86% | 2746 fps | 98.6% |
| IMR 7828 SSC | <<locked>> | 98% | 54,984 psi | 86% | 2854 fps | 99.1% |
| Lovex S062 | <<locked>> | 82% | 56,739 psi | 89% | 2694 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 56,463 psi | 88% | 2730 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 54,592 psi | 86% | 2726 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 50,546 psi | 79% | 2687 fps | 100% |
| Norma 203B | <<locked>> | 82% | 57,566 psi | 90% | 2749 fps | 100% |
| Norma 204 | <<locked>> | 90% | 56,927 psi | 89% | 2805 fps | 99.6% |
| Norma 217ᴾ | <<locked>> | 100% | 34,838 psi | 55% | 2543 fps | 97% |
| Norma MRP | <<locked>> | 96% | 56,739 psi | 89% | 2894 fps | 100% |
| Norma URP | <<locked>> | 90% | 57,319 psi | 90% | 2795 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 55,521 psi | 87% | 2874 fps | 99.4% |
| Ramshot Hunter | <<locked>> | 90% | 56,115 psi | 88% | 2802 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 53,476 psi | 84% | 2805 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,550 psi | 59% | 1729 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 55,463 psi | 87% | 2720 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 56,942 psi | 89% | 2815 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 55,100 psi | 86% | 2785 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 57,348 psi | 90% | 2867 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 49,066 psi | 77% | 2848 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 43,845 psi | 69% | 2726 fps | 96.1% |
| Rottweil R 903 | <<locked>> | 84% | 55,666 psi | 87% | 2710 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 57,551 psi | 90% | 2789 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 94% | 54,781 psi | 86% | 2792 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 86% | 54,621 psi | 86% | 2710 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 88% | 56,463 psi | 88% | 2730 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 56,739 psi | 89% | 2694 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 54,592 psi | 86% | 2726 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 57,290 psi | 90% | 2766 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 56,101 psi | 88% | 2585 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 55,927 psi | 88% | 2687 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 54,346 psi | 85% | 2789 fps | 99.6% |
| Somchem S355 | <<locked>> | 84% | 55,448 psi | 87% | 2703 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 55,317 psi | 87% | 2726 fps | 98.4% |
| Somchem S365 | <<locked>> | 92% | 57,406 psi | 90% | 2792 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 55,245 psi | 87% | 2766 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 86% | 56,710 psi | 89% | 2677 fps | 100% |
| Vihtavuori N160 | <<locked>> | 88% | 55,709 psi | 87% | 2736 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 54,679 psi | 86% | 2746 fps | 99.8% |
| Vihtavuori N540 | <<locked>> | 82% | 57,363 psi | 90% | 2671 fps | 100% |
| Vihtavuori N550 | <<locked>> | 88% | 54,781 psi | 86% | 2743 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 56,362 psi | 88% | 2808 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 56,782 psi | 89% | 2890 fps | 99% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 52,214 psi | 82% | 2805 fps | 98.5% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 55,259 psi | 87% | 2700 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 57,319 psi | 90% | 2818 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 54,621 psi | 86% | 2917 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 55,288 psi | 87% | 2762 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 2700 | <<locked>> | 80% | 53,896 psi | 84% | 2664 fps | 99.7% |
| Accurate 3100 | <<locked>> | 80% | 30,560 psi | 48% | 2303 fps | 96.7% |
| Accurate 4064 | <<locked>> | 80% | 53,563 psi | 84% | 2635 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 41,669 psi | 65% | 2549 fps | 99.9% |
| Accurate High Country | 95.1 gr | 84% | 38,334 psi | 60% | 2572 fps | 95.6% |
| Accurate MAGPRO | <<locked>> | 88% | 41,727 psi | 65% | 2635 fps | 95.2% |
| ADI AR 2208 | <<locked>> | 80% | 50,444 psi | 79% | 2628 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 35,085 psi | 55% | 2428 fps | 95.4% |
| ADI AR 2213 | <<locked>> | 86% | 38,174 psi | 60% | 2526 fps | 95% |
| ADI AR 2217 | <<locked>> | 96% | 38,986 psi | 61% | 2543 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 92% | 30,414 psi | 48% | 2385 fps | 95.2% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 35,346 psi | 55% | 2431 fps | 95.5% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 35,346 psi | 55% | 2431 fps | 95.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 51,242 psi | 80% | 2648 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 40,306 psi | 63% | 2559 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 46,427 psi | 73% | 2674 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 35,012 psi | 55% | 2428 fps | 95.5% |
| Alliant Reloder-22 | <<locked>> | 84% | 35,273 psi | 55% | 2477 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,573 psi | 46% | 2336 fps | 99.3% |
| Alliant Reloder-25 | <<locked>> | 82% | 27,630 psi | 43% | 2297 fps | 95.8% |
| Alliant Reloder-26 | 93.3 gr | 80% | 31,908 psi | 50% | 2457 fps | 98.6% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 49,400 psi | 77% | 2674 fps | 95% |
| Bofors RP15 | <<locked>> | 86% | 35,041 psi | 55% | 2470 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 51,851 psi | 81% | 2661 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 37,231 psi | 58% | 2556 fps | 95.6% |
| Bofors RP5 | <<locked>> | 84% | 35,273 psi | 55% | 2477 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 45,136 psi | 71% | 2556 fps | 98.9% |
| Hodgdon H1000 | <<locked>> | 92% | 37,391 psi | 59% | 2510 fps | 95.6% |
| Hodgdon H380 | <<locked>> | 80% | 52,011 psi | 82% | 2680 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 43,714 psi | 69% | 2598 fps | 99.1% |
| Hodgdon H4350 | <<locked>> | 80% | 46,557 psi | 73% | 2615 fps | 98.7% |
| Hodgdon H4831 | <<locked>> | 86% | 40,828 psi | 64% | 2536 fps | 95.3% |
| Hodgdon H4831 SC | <<locked>> | 86% | 40,059 psi | 63% | 2520 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 37,942 psi | 59% | 2451 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 32,793 psi | 51% | 2484 fps | 95% |
| Hodgdon Superformance | <<locked>> | 80% | 42,728 psi | 67% | 2618 fps | 98.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,543 psi | 43% | 1509 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 53,084 psi | 83% | 2654 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 40,727 psi | 64% | 2493 fps | 98.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 46,717 psi | 73% | 2585 fps | 99.4% |
| IMR 4831 | <<locked>> | 80% | 39,827 psi | 62% | 2500 fps | 99.9% |
| IMR 4955 Enduron | <<locked>> | 84% | 40,190 psi | 63% | 2487 fps | 95.3% |
| IMR 7828 SSC | <<locked>> | 88% | 39,131 psi | 61% | 2562 fps | 95.5% |
| Lovex S062 | <<locked>> | 80% | 53,185 psi | 83% | 2644 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 44,005 psi | 69% | 2533 fps | 99.7% |
| Lovex S070 | <<locked>> | 80% | 42,322 psi | 66% | 2523 fps | 99% |
| Lovex S071 | <<locked>> | 82% | 28,007 psi | 44% | 2234 fps | 95.5% |
| Norma 203B | <<locked>> | 80% | 53,954 psi | 85% | 2700 fps | 100% |
| Norma 204 | <<locked>> | 80% | 40,393 psi | 63% | 2523 fps | 97% |
| Norma 217 | <<locked>> | 98% | 32,503 psi | 51% | 2480 fps | 95.9% |
| Norma MRP | <<locked>> | 80% | 32,082 psi | 50% | 2428 fps | 96% |
| Norma URP | <<locked>> | 80% | 41,321 psi | 65% | 2543 fps | 99.9% |
| Ramshot Grand | <<locked>> | 88% | 38,653 psi | 61% | 2569 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 40,074 psi | 63% | 2536 fps | 99.1% |
| Ramshot Magnum | <<locked>> | 86% | 31,865 psi | 50% | 2388 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,007 psi | 44% | 1545 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 51,880 psi | 81% | 2667 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 49,356 psi | 77% | 2713 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 41,669 psi | 65% | 2572 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 40,118 psi | 63% | 2589 fps | 99.8% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 31,865 psi | 50% | 2461 fps | 95.9% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 40,770 psi | 64% | 2661 fps | 95% |
| Rottweil R 903 | <<locked>> | 80% | 48,834 psi | 77% | 2612 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 38,972 psi | 61% | 2467 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 80% | 34,113 psi | 53% | 2408 fps | 95.3% |
| Rottweil R 907 | <<locked>> | 80% | 45,136 psi | 71% | 2556 fps | 98.9% |
| Shooters World Long Rifle | <<locked>> | 80% | 44,005 psi | 69% | 2533 fps | 99.7% |
| Shooters World Precision | <<locked>> | 80% | 53,185 psi | 83% | 2644 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 42,322 psi | 66% | 2523 fps | 99% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 50,154 psi | 79% | 2667 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 49,588 psi | 78% | 2500 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 43,062 psi | 67% | 2484 fps | 99% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 33,794 psi | 53% | 2405 fps | 95.2% |
| Somchem S355 | <<locked>> | 80% | 48,820 psi | 77% | 2608 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 42,380 psi | 66% | 2510 fps | 95.7% |
| Somchem S365 | <<locked>> | 80% | 37,942 psi | 59% | 2500 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 34,751 psi | 54% | 2398 fps | 96.5% |
| Vihtavuori N150 | <<locked>> | 80% | 46,760 psi | 73% | 2539 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 42,714 psi | 67% | 2536 fps | 100% |
| Vihtavuori N165 | <<locked>> | 82% | 32,039 psi | 50% | 2329 fps | 95% |
| Vihtavuori N540 | <<locked>> | 80% | 53,853 psi | 84% | 2625 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 42,076 psi | 66% | 2539 fps | 99.9% |
| Vihtavuori N555 | <<locked>> | 80% | 33,069 psi | 52% | 2405 fps | 99.3% |
| Vihtavuori N560 | 97.4 gr | 86% | 40,089 psi | 63% | 2595 fps | 95.4% |
| Vihtavuori N565 | <<locked>> | 92% | 39,465 psi | 62% | 2575 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 41,713 psi | 65% | 2503 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 43,830 psi | 69% | 2602 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 26,034 psi | 41% | 2336 fps | 99.3% |
| Winchester Supreme 780 | <<locked>> | 82% | 33,866 psi | 53% | 2375 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 89 powders for .378 Weath. Mag. loaded with the .375 | 300gr | Reichenberg Super Penetra. Winchester StaBALL HD delivers the highest muzzle velocity at 2,917 fps; across all powders the maximum-charge window runs from 1,690 fps to 2,917 fps. ADI AR 2217 gives the best case fill at 100 %, and 89 of the 89 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 55–90 %, 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. Accurate High Country, Alliant Reloder-26, Vihtavuori N560 rank at the top here: for .378 Weath. Mag. with the .375 | 300gr | Reichenberg Super Penetra 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.