Load Specifications
Load data in caliber .375 Swiss P with .375 | 250gr | Barnes Solid BT bullet and 97 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 70, Alliant Reloder-16 and Hodgdon Superformance.
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: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 84% | 52,489 psi | 86% | 2789 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 54,360 psi | 89% | 2848 fps | 98% |
| Accurate 3100ᴾ | <<locked>> | 100% | 46,789 psi | 77% | 2815 fps | 98.3% |
| Accurate 4064 | <<locked>> | 86% | 52,808 psi | 87% | 2841 fps | 100% |
| Accurate 4350 | <<locked>> | 94% | 52,808 psi | 87% | 2936 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 82% | 52,504 psi | 86% | 2871 fps | 100% |
| ADI AR 2208 | <<locked>> | 88% | 53,548 psi | 88% | 2874 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 54,317 psi | 89% | 2969 fps | 97.2% |
| ADI Benchmark 8208 | <<locked>> | 82% | 54,694 psi | 90% | 2867 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 52,199 psi | 86% | 2989 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 53,838 psi | 88% | 2894 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 86% | 54,331 psi | 89% | 2920 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 96% | 53,780 psi | 88% | 2992 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 92% | 54,969 psi | 90% | 3025 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 53,229 psi | 87% | 2956 fps | 97.2% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 46,862 psi | 77% | 2890 fps | 95.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 44,106 psi | 72% | 2841 fps | 99.9% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 38,856 psi | 64% | 2746 fps | 97% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 50,053 psi | 82% | 3025 fps | 99.8% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 52,098 psi | 86% | 2884 fps | 99.8% |
| Bofors RP3 | <<locked>> | 88% | 54,491 psi | 89% | 2910 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 46,862 psi | 77% | 2890 fps | 95.9% |
| Bofors RP7 | <<locked>> | 92% | 54,346 psi | 89% | 2887 fps | 98.2% |
| Hodgdon BL-C2 | <<locked>> | 82% | 54,259 psi | 89% | 2897 fps | 100% |
| Hodgdon H380 | <<locked>> | 86% | 51,677 psi | 85% | 2871 fps | 99.6% |
| Hodgdon H414 | <<locked>> | 92% | 51,808 psi | 85% | 2930 fps | 98.4% |
| Hodgdon H4350 | <<locked>> | 90% | 52,228 psi | 86% | 2890 fps | 97.2% |
| Hodgdon H4895 | <<locked>> | 82% | 53,055 psi | 87% | 2881 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 98% | 53,824 psi | 88% | 2917 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 52,678 psi | 86% | 2913 fps | 100% |
| Hodgdon Superformance | <<locked>> | 92% | 51,779 psi | 85% | 2963 fps | 98.1% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,013 psi | 59% | 1791 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 54,085 psi | 89% | 2881 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 53,287 psi | 87% | 2858 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 52,953 psi | 87% | 2854 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 52,576 psi | 86% | 2835 fps | 98.3% |
| IMR 4350 | <<locked>> | 96% | 54,911 psi | 90% | 2917 fps | 98.3% |
| IMR 4451 Enduron | <<locked>> | 90% | 52,779 psi | 87% | 2864 fps | 98.3% |
| IMR 4831 | <<locked>> | 96% | 53,345 psi | 88% | 2927 fps | 99.9% |
| IMR 4895 | <<locked>> | 84% | 52,301 psi | 86% | 2894 fps | 100% |
| IMR 8208 XBR | <<locked>> | 82% | 54,694 psi | 90% | 2867 fps | 100% |
| Lovex D073.6 | <<locked>> | 82% | 52,431 psi | 86% | 2844 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 55,013 psi | 90% | 2844 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 53,011 psi | 87% | 2851 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 52,533 psi | 86% | 2861 fps | 99.2% |
| Lovex S070 | <<locked>> | 94% | 53,534 psi | 88% | 2900 fps | 98.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 38,914 psi | 64% | 2664 fps | 96.4% |
| Norma 201 | <<locked>> | 84% | 54,534 psi | 90% | 2861 fps | 100% |
| Norma 202 | <<locked>> | 82% | 51,779 psi | 85% | 2812 fps | 100% |
| Norma 203B | <<locked>> | 86% | 53,563 psi | 88% | 2904 fps | 100% |
| Norma 204 | <<locked>> | 94% | 51,982 psi | 85% | 2910 fps | 96.7% |
| Norma MRPᴾ | <<locked>> | 100% | 49,603 psi | 81% | 2979 fps | 98% |
| Norma URP | <<locked>> | 94% | 51,837 psi | 85% | 2923 fps | 99.8% |
| Ramshot Big Game | <<locked>> | 86% | 54,099 psi | 89% | 2930 fps | 100% |
| Ramshot Hunter | <<locked>> | 96% | 53,969 psi | 89% | 2972 fps | 99.3% |
| Ramshot TAC | <<locked>> | 82% | 54,781 psi | 90% | 2890 fps | 99.5% |
| Ramshot Wild Boar | <<locked>> | 82% | 54,650 psi | 90% | 2907 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,492 psi | 60% | 1834 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 51,808 psi | 85% | 2851 fps | 98.7% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 54,868 psi | 90% | 2986 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 54,592 psi | 90% | 3018 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 52,489 psi | 86% | 2956 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 51,488 psi | 85% | 2982 fps | 99.7% |
| Rottweil R 902 | <<locked>> | 84% | 51,851 psi | 85% | 2815 fps | 100% |
| Rottweil R 903 | <<locked>> | 90% | 54,549 psi | 90% | 2904 fps | 100% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 52,112 psi | 86% | 2940 fps | 97.2% |
| Rottweil R 907 | <<locked>> | 92% | 54,346 psi | 89% | 2887 fps | 98.2% |
| Shooters World Long Rifle | <<locked>> | 92% | 52,533 psi | 86% | 2861 fps | 99.2% |
| Shooters World Match Rifle | <<locked>> | 82% | 52,431 psi | 86% | 2844 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 53,011 psi | 87% | 2851 fps | 100% |
| Shooters World SW4350 | <<locked>> | 94% | 53,534 psi | 88% | 2900 fps | 98.7% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 52,562 psi | 86% | 2913 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 53,330 psi | 88% | 2867 fps | 99.6% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 54,230 psi | 89% | 2890 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 52,402 psi | 86% | 2749 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 52,968 psi | 87% | 2753 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 52,373 psi | 86% | 2812 fps | 98.3% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 51,634 psi | 85% | 2933 fps | 97% |
| Somchem S335 | <<locked>> | 82% | 52,069 psi | 85% | 2749 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 53,026 psi | 87% | 2858 fps | 100% |
| Somchem S355 | <<locked>> | 90% | 54,679 psi | 90% | 2900 fps | 100% |
| Somchem S365 | <<locked>> | 98% | 53,867 psi | 88% | 2976 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 52,968 psi | 87% | 2920 fps | 98% |
| Vihtavuori N133 | <<locked>> | 82% | 52,808 psi | 87% | 2733 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 51,909 psi | 85% | 2779 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 52,431 psi | 86% | 2792 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 52,605 psi | 86% | 2828 fps | 100% |
| Vihtavuori N160 | <<locked>> | 94% | 54,085 psi | 89% | 2917 fps | 99.9% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 45,629 psi | 75% | 2776 fps | 96% |
| Vihtavuori N540 | <<locked>> | 86% | 53,838 psi | 88% | 2835 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 53,113 psi | 87% | 2920 fps | 99.8% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 49,110 psi | 81% | 2920 fps | 99.9% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 53,969 psi | 89% | 2890 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 51,982 psi | 85% | 2933 fps | 98.4% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 39,726 psi | 65% | 2877 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 84% | 54,186 psi | 89% | 2900 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 49,676 psi | 82% | 2851 fps | 96.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 46,122 psi | 76% | 2694 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 44,643 psi | 73% | 2677 fps | 95.9% |
| Accurate 3100 | <<locked>> | 92% | 35,607 psi | 58% | 2592 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 43,656 psi | 72% | 2697 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 32,590 psi | 54% | 2536 fps | 96.1% |
| ADI AR 2206H | <<locked>> | 80% | 49,313 psi | 81% | 2818 fps | 99.9% |
| ADI AR 2208 | <<locked>> | 80% | 41,843 psi | 69% | 2664 fps | 99% |
| ADI AR 2209 | <<locked>> | 96% | 47,674 psi | 78% | 2854 fps | 95.7% |
| ADI Benchmark 8208 | <<locked>> | 80% | 51,358 psi | 84% | 2818 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 45,339 psi | 74% | 2867 fps | 99.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 41,930 psi | 69% | 2690 fps | 99.8% |
| Alliant Reloder-15 | <<locked>> | 80% | 44,875 psi | 74% | 2756 fps | 99.5% |
| Alliant Reloder-16 | 78.1 gr | 80% | 32,547 psi | 53% | 2546 fps | 96.2% |
| Alliant Reloder-17 | <<locked>> | 80% | 36,434 psi | 60% | 2677 fps | 99% |
| Alliant Reloder-19 | <<locked>> | 96% | 46,891 psi | 77% | 2844 fps | 95.7% |
| Alliant Reloder-22 | <<locked>> | 98% | 43,947 psi | 72% | 2835 fps | 95.1% |
| Alliant Reloder-23 | <<locked>> | 84% | 26,745 psi | 44% | 2402 fps | 95% |
| Alliant Reloder-25 | <<locked>> | 96% | 34,316 psi | 56% | 2628 fps | 95% |
| Alliant Reloder-26 | <<locked>> | 88% | 32,663 psi | 54% | 2635 fps | 95.4% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 48,805 psi | 80% | 2828 fps | 99.6% |
| Bofors RP3 | <<locked>> | 80% | 41,814 psi | 69% | 2697 fps | 99.8% |
| Bofors RP5 | <<locked>> | 98% | 43,947 psi | 72% | 2835 fps | 95.1% |
| Bofors RP7 | <<locked>> | 84% | 42,351 psi | 70% | 2671 fps | 95.6% |
| Hodgdon BL-C2 | <<locked>> | 80% | 50,763 psi | 83% | 2844 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 42,467 psi | 70% | 2703 fps | 98.3% |
| Hodgdon H414 | <<locked>> | 84% | 39,726 psi | 65% | 2697 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 84% | 43,062 psi | 71% | 2723 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 49,792 psi | 82% | 2828 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 29,921 psi | 49% | 2444 fps | 96.9% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 46,021 psi | 76% | 2802 fps | 100% |
| Hodgdon Superformance | 95.5 gr | 86% | 41,727 psi | 69% | 2769 fps | 95.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,803 psi | 44% | 1601 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 47,601 psi | 78% | 2776 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 50,024 psi | 82% | 2812 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 43,976 psi | 72% | 2700 fps | 99.4% |
| IMR 4166 Enduron | <<locked>> | 80% | 46,267 psi | 76% | 2720 fps | 97.1% |
| IMR 4350 | <<locked>> | 88% | 42,714 psi | 70% | 2700 fps | 95.7% |
| IMR 4451 Enduron | <<locked>> | 82% | 41,278 psi | 68% | 2651 fps | 95.8% |
| IMR 4831 | <<locked>> | 80% | 31,531 psi | 52% | 2490 fps | 95.7% |
| IMR 4895 | <<locked>> | 80% | 46,021 psi | 76% | 2785 fps | 99.8% |
| IMR 8208 XBR | <<locked>> | 80% | 51,358 psi | 84% | 2818 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 49,023 psi | 80% | 2792 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 48,733 psi | 80% | 2746 fps | 99.9% |
| Lovex S062 | <<locked>> | 80% | 44,077 psi | 72% | 2700 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 36,274 psi | 60% | 2543 fps | 95.8% |
| Lovex S070 | <<locked>> | 84% | 39,189 psi | 64% | 2631 fps | 95.5% |
| Lovex S071 | <<locked>> | 98% | 36,492 psi | 60% | 2612 fps | 95.6% |
| Norma 201 | <<locked>> | 80% | 48,167 psi | 79% | 2762 fps | 100% |
| Norma 202 | <<locked>> | 80% | 48,733 psi | 80% | 2766 fps | 100% |
| Norma 203B | <<locked>> | 80% | 44,251 psi | 73% | 2743 fps | 99.7% |
| Norma 204 | <<locked>> | 90% | 45,324 psi | 74% | 2792 fps | 95% |
| Norma MRP | <<locked>> | 94% | 40,364 psi | 66% | 2789 fps | 95.5% |
| Norma URP | <<locked>> | 80% | 32,764 psi | 54% | 2536 fps | 96% |
| Ramshot Big Game | <<locked>> | 80% | 44,106 psi | 72% | 2762 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 84% | 36,332 psi | 60% | 2628 fps | 95.3% |
| Ramshot TAC | <<locked>> | 80% | 51,213 psi | 84% | 2835 fps | 99.2% |
| Ramshot Wild Boar | <<locked>> | 80% | 51,053 psi | 84% | 2851 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,195 psi | 45% | 1637 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 42,714 psi | 70% | 2687 fps | 97% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 47,921 psi | 79% | 2871 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 38,725 psi | 64% | 2736 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 32,242 psi | 53% | 2549 fps | 95.5% |
| ReloadSwiss RS 70 | 87.5 gr | 82% | 34,214 psi | 56% | 2608 fps | 95.5% |
| Rottweil R 902 | <<locked>> | 80% | 45,934 psi | 75% | 2717 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 39,407 psi | 65% | 2641 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 96% | 45,745 psi | 75% | 2825 fps | 95.6% |
| Rottweil R 907 | <<locked>> | 84% | 42,351 psi | 70% | 2671 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 36,274 psi | 60% | 2543 fps | 95.8% |
| Shooters World Match Rifle | <<locked>> | 80% | 49,023 psi | 80% | 2792 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 44,077 psi | 72% | 2700 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 39,189 psi | 64% | 2631 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 40,393 psi | 66% | 2694 fps | 99.1% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 49,893 psi | 82% | 2812 fps | 99.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 47,718 psi | 78% | 2785 fps | 99.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 49,255 psi | 81% | 2703 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 41,307 psi | 68% | 2569 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 40,364 psi | 66% | 2592 fps | 95.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 45,295 psi | 74% | 2818 fps | 95.5% |
| Somchem S335 | <<locked>> | 80% | 48,936 psi | 80% | 2700 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 49,676 psi | 82% | 2805 fps | 99.9% |
| Somchem S355 | <<locked>> | 80% | 39,943 psi | 66% | 2644 fps | 99.4% |
| Somchem S365 | <<locked>> | 80% | 29,356 psi | 48% | 2487 fps | 98.1% |
| Somchem S385 | <<locked>> | 92% | 40,741 psi | 67% | 2694 fps | 95.1% |
| Vihtavuori N133 | <<locked>> | 80% | 49,690 psi | 82% | 2690 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 45,759 psi | 75% | 2687 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 46,151 psi | 76% | 2697 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 38,101 psi | 63% | 2575 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 80% | 34,142 psi | 56% | 2536 fps | 96.4% |
| Vihtavuori N165 | <<locked>> | 98% | 42,714 psi | 70% | 2720 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 44,512 psi | 73% | 2690 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 33,620 psi | 55% | 2536 fps | 96% |
| Vihtavuori N555 | <<locked>> | 84% | 28,921 psi | 47% | 2480 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 33,678 psi | 55% | 2510 fps | 98.4% |
| Winchester 760 | <<locked>> | 84% | 39,842 psi | 65% | 2703 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 88% | 26,789 psi | 44% | 2480 fps | 95.6% |
| Winchester StaBALL Match | <<locked>> | 80% | 47,398 psi | 78% | 2792 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 46,267 psi | 76% | 2792 fps | 95.4% |
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 97 powders for .375 Swiss P loaded with the .375 | 250gr | Barnes Solid BT. Alliant Reloder-17 delivers the highest muzzle velocity at 3,025 fps; across all powders the maximum-charge window runs from 1,791 fps to 3,025 fps. Accurate 3100 gives the best case fill at 100 %, and 97 of the 97 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (420 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 250.0 gr projectile in 0.375" calls for a 1:15.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, Alliant Reloder-19 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. ReloadSwiss RS 70, Alliant Reloder-16, Hodgdon Superformance rank at the top here: for .375 Swiss P with the .375 | 250gr | Barnes Solid BT 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.