Load Specifications
Load data in caliber .375 Rem. Ultra Mag. with .375 | 200gr | Impala LWHV LS bullet and 97 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Power Pro 2000-MR, ReloadSwiss RS 60 and Alliant Reloder-17.
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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 86% | 56,405 psi | 88% | 2936 fps | 100% |
| Accurate 2460 | <<locked>> | 82% | 55,158 psi | 86% | 2959 fps | 100% |
| Accurate 2495 | <<locked>> | 90% | 55,883 psi | 88% | 2963 fps | 100% |
| Accurate 2520 | <<locked>> | 86% | 56,797 psi | 89% | 3015 fps | 100% |
| Accurate 4064 | <<locked>> | 92% | 55,477 psi | 87% | 3002 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 54,128 psi | 85% | 3048 fps | 98.4% |
| Accurate LT-30 | <<locked>> | 82% | 57,667 psi | 90% | 2917 fps | 100% |
| ADI AR 2206H | <<locked>> | 88% | 55,143 psi | 86% | 3018 fps | 99.3% |
| ADI AR 2208 | <<locked>> | 94% | 55,811 psi | 87% | 3009 fps | 98.9% |
| ADI Benchmark 8208 | <<locked>> | 88% | 57,406 psi | 90% | 3022 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 86% | 54,404 psi | 85% | 2966 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 82% | 55,709 psi | 87% | 3087 fps | 99.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 90% | 54,346 psi | 85% | 3117 fps | 98.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 94% | 56,014 psi | 88% | 3038 fps | 99.8% |
| Alliant Reloder-10x | <<locked>> | 82% | 55,724 psi | 87% | 2946 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 92% | 56,536 psi | 89% | 3054 fps | 99.1% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 51,851 psi | 81% | 3041 fps | 98.3% |
| Alliant Reloder-17 | <<locked>> | 98% | 56,565 psi | 89% | 3146 fps | 99.8% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 37,797 psi | 59% | 2766 fps | 96.1% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 57,188 psi | 90% | 2904 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 88% | 54,737 psi | 86% | 3022 fps | 98.6% |
| Bofors RP3 | <<locked>> | 94% | 57,000 psi | 89% | 3054 fps | 99.9% |
| Hodgdon Benchmark | <<locked>> | 86% | 55,999 psi | 88% | 2963 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 88% | 57,130 psi | 90% | 3054 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 84% | 54,723 psi | 86% | 3087 fps | 99% |
| Hodgdon H322 | <<locked>> | 82% | 54,491 psi | 85% | 2979 fps | 100% |
| Hodgdon H335 | <<locked>> | 82% | 55,811 psi | 87% | 2999 fps | 100% |
| Hodgdon H380 | <<locked>> | 92% | 54,404 psi | 85% | 3005 fps | 97.9% |
| Hodgdon H414ᴾ | <<locked>> | 100% | 56,652 psi | 89% | 3087 fps | 96.3% |
| Hodgdon H4895 | <<locked>> | 88% | 55,608 psi | 87% | 3031 fps | 99.6% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 48,153 psi | 75% | 2923 fps | 98.8% |
| Hodgdon LEVERevolution | <<locked>> | 90% | 54,650 psi | 86% | 3054 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,331 psi | 55% | 1890 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 56,637 psi | 89% | 3028 fps | 99.6% |
| IMR 3031 | <<locked>> | 88% | 55,100 psi | 86% | 3025 fps | 100% |
| IMR 4064 | <<locked>> | 92% | 55,361 psi | 87% | 2992 fps | 99% |
| IMR 4166 Enduron | <<locked>> | 90% | 55,840 psi | 88% | 2966 fps | 95.9% |
| IMR 4198 | <<locked>> | 82% | 55,143 psi | 86% | 2904 fps | 100% |
| IMR 4831ᴾ | <<locked>> | 100% | 51,140 psi | 80% | 2982 fps | 98% |
| IMR 4895 | <<locked>> | 90% | 54,563 psi | 86% | 3038 fps | 99.3% |
| IMR 8208 XBR | <<locked>> | 88% | 57,406 psi | 90% | 3022 fps | 99.9% |
| Lovex D073.5 | <<locked>> | 82% | 54,969 psi | 86% | 2963 fps | 100% |
| Lovex D073.6 | <<locked>> | 88% | 55,027 psi | 86% | 2999 fps | 100% |
| Lovex S060 | <<locked>> | 88% | 54,723 psi | 86% | 2943 fps | 99.2% |
| Lovex S062 | <<locked>> | 92% | 55,564 psi | 87% | 2999 fps | 99.9% |
| Lovex S065 | <<locked>> | 98% | 54,795 psi | 86% | 2979 fps | 97.2% |
| Lovex S070ᴾ | <<locked>> | 100% | 55,564 psi | 87% | 3009 fps | 96.2% |
| Norma 201 | <<locked>> | 88% | 54,476 psi | 85% | 2972 fps | 99.8% |
| Norma 202 | <<locked>> | 88% | 54,447 psi | 85% | 2976 fps | 100% |
| Norma 203B | <<locked>> | 92% | 55,724 psi | 87% | 3045 fps | 99.4% |
| Norma URPᴾ | <<locked>> | 100% | 52,924 psi | 83% | 3031 fps | 98.1% |
| Ramshot Big Game | <<locked>> | 92% | 56,231 psi | 88% | 3064 fps | 99.4% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 51,982 psi | 81% | 3015 fps | 96.3% |
| Ramshot TAC | <<locked>> | 86% | 54,679 psi | 86% | 2976 fps | 97.3% |
| Ramshot Wild Boar | <<locked>> | 88% | 57,580 psi | 90% | 3054 fps | 99.5% |
| Ramshot X-Terminator | <<locked>> | 84% | 55,332 psi | 87% | 2969 fps | 99.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,810 psi | 56% | 1932 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 84% | 57,014 psi | 89% | 3009 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 92% | 54,607 psi | 86% | 2976 fps | 96.4% |
| ReloadSwiss RS 52 | <<locked>> | 90% | 56,695 psi | 89% | 3123 fps | 99.1% |
| ReloadSwiss RS 60 | <<locked>> | 96% | 56,405 psi | 88% | 3153 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 53,359 psi | 84% | 3058 fps | 98.1% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 53,621 psi | 84% | 3077 fps | 97.6% |
| Rottweil R 901 | <<locked>> | 86% | 55,825 psi | 87% | 2969 fps | 100% |
| Rottweil R 902 | <<locked>> | 90% | 54,926 psi | 86% | 2969 fps | 99.8% |
| Rottweil R 903 | <<locked>> | 96% | 56,724 psi | 89% | 3045 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 98% | 54,795 psi | 86% | 2979 fps | 97.2% |
| Shooters World Match Rifle | <<locked>> | 88% | 55,027 psi | 86% | 2999 fps | 100% |
| Shooters World Precision | <<locked>> | 92% | 55,564 psi | 87% | 2999 fps | 99.9% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 55,564 psi | 87% | 3009 fps | 96.2% |
| Shooters World Tactical Rifle | <<locked>> | 82% | 56,797 psi | 89% | 2972 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 94% | 54,346 psi | 85% | 3041 fps | 99.2% |
| SNPE Vectan SP 3 | <<locked>> | 82% | 56,159 psi | 88% | 2963 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 88% | 56,739 psi | 89% | 3009 fps | 98.1% |
| SNPE Vectan SP 9 | <<locked>> | 90% | 56,927 psi | 89% | 3035 fps | 99.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 88% | 55,608 psi | 87% | 2913 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 94% | 55,347 psi | 87% | 2904 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 98% | 55,332 psi | 87% | 2927 fps | 95.8% |
| Somchem S321 | <<locked>> | 84% | 55,593 psi | 87% | 3009 fps | 99.9% |
| Somchem S335 | <<locked>> | 88% | 55,201 psi | 87% | 2913 fps | 100% |
| Somchem S341 | <<locked>> | 88% | 55,912 psi | 88% | 2999 fps | 99.3% |
| Somchem S355 | <<locked>> | 96% | 56,913 psi | 89% | 3041 fps | 99.7% |
| Somchem S365ᴾ | <<locked>> | 100% | 47,587 psi | 75% | 2982 fps | 99.7% |
| Vihtavuori N130 | <<locked>> | 84% | 55,317 psi | 87% | 2887 fps | 100% |
| Vihtavuori N133 | <<locked>> | 88% | 55,492 psi | 87% | 2900 fps | 100% |
| Vihtavuori N135 | <<locked>> | 92% | 57,232 psi | 90% | 2986 fps | 100% |
| Vihtavuori N140 | <<locked>> | 90% | 54,868 psi | 86% | 2953 fps | 100% |
| Vihtavuori N150 | <<locked>> | 96% | 54,911 psi | 86% | 2969 fps | 99.9% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 55,419 psi | 87% | 3028 fps | 98.4% |
| Vihtavuori N530 | <<locked>> | 86% | 54,636 psi | 86% | 2972 fps | 99.8% |
| Vihtavuori N540 | <<locked>> | 92% | 56,681 psi | 89% | 2992 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 54,795 psi | 86% | 3035 fps | 98.2% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 40,712 psi | 64% | 2851 fps | 96.2% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 56,391 psi | 88% | 3005 fps | 99.8% |
| Winchester 748 | <<locked>> | 86% | 54,230 psi | 85% | 3018 fps | 100% |
| Winchester 760ᴾ | <<locked>> | 100% | 56,913 psi | 89% | 3094 fps | 96.4% |
| Winchester StaBALL Match | <<locked>> | 90% | 56,884 psi | 89% | 3045 fps | 99.7% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 80% | 47,181 psi | 74% | 2799 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 51,619 psi | 81% | 2904 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 41,046 psi | 64% | 2730 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 46,702 psi | 73% | 2861 fps | 99.8% |
| Accurate 4064 | <<locked>> | 80% | 38,653 psi | 61% | 2713 fps | 99.5% |
| Accurate 4350 | <<locked>> | 92% | 41,466 psi | 65% | 2825 fps | 95.5% |
| Accurate LT-30 | <<locked>> | 80% | 54,317 psi | 85% | 2871 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 43,265 psi | 68% | 2805 fps | 97.3% |
| ADI AR 2208 | <<locked>> | 82% | 39,204 psi | 61% | 2700 fps | 95.4% |
| ADI Benchmark 8208 | <<locked>> | 80% | 45,034 psi | 71% | 2815 fps | 98.7% |
| Alliant AR-Comp | <<locked>> | 80% | 44,846 psi | 70% | 2825 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 52,185 psi | 82% | 3028 fps | 99.3% |
| Alliant Power Pro 2000-MR | 80.7 gr | 82% | 41,785 psi | 65% | 2871 fps | 95.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 36,550 psi | 57% | 2674 fps | 96.4% |
| Alliant Reloder-10x | <<locked>> | 80% | 52,591 psi | 82% | 2900 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 39,189 psi | 61% | 2733 fps | 95.6% |
| Alliant Reloder-16 | <<locked>> | 92% | 40,915 psi | 64% | 2822 fps | 95.3% |
| Alliant Reloder-17 | 81.4 gr | 84% | 36,085 psi | 57% | 2733 fps | 95.4% |
| Alliant Reloder-23 | <<locked>> | 98% | 35,723 psi | 56% | 2713 fps | 95.2% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 53,882 psi | 84% | 2861 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 42,279 psi | 66% | 2795 fps | 95.9% |
| Bofors RP3 | <<locked>> | 80% | 36,448 psi | 57% | 2677 fps | 96.5% |
| Hodgdon Benchmark | <<locked>> | 80% | 46,862 psi | 73% | 2808 fps | 99.3% |
| Hodgdon BL-C2 | <<locked>> | 80% | 44,150 psi | 69% | 2838 fps | 99% |
| Hodgdon CFE223 | <<locked>> | 80% | 47,761 psi | 75% | 2969 fps | 97.8% |
| Hodgdon H322 | <<locked>> | 80% | 51,213 psi | 80% | 2930 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 52,257 psi | 82% | 2946 fps | 100% |
| Hodgdon H380 | <<locked>> | 84% | 42,221 psi | 66% | 2782 fps | 95% |
| Hodgdon H414 | <<locked>> | 98% | 53,142 psi | 83% | 3031 fps | 95.5% |
| Hodgdon H4895 | <<locked>> | 80% | 43,584 psi | 68% | 2818 fps | 97.9% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 35,694 psi | 56% | 2664 fps | 95.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 39,392 psi | 62% | 2776 fps | 97.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,455 psi | 41% | 1696 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 41,756 psi | 65% | 2766 fps | 97.4% |
| IMR 3031 | <<locked>> | 80% | 42,772 psi | 67% | 2828 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 38,725 psi | 61% | 2684 fps | 95.5% |
| IMR 4166 Enduron | <<locked>> | 88% | 52,431 psi | 82% | 2910 fps | 95.1% |
| IMR 4198 | <<locked>> | 80% | 51,982 psi | 81% | 2861 fps | 100% |
| IMR 4831 | <<locked>> | 92% | 39,798 psi | 62% | 2769 fps | 95.1% |
| IMR 4895 | <<locked>> | 80% | 40,045 psi | 63% | 2766 fps | 96.5% |
| IMR 8208 XBR | <<locked>> | 80% | 45,034 psi | 71% | 2815 fps | 98.7% |
| Lovex D073.5 | <<locked>> | 80% | 51,517 psi | 81% | 2910 fps | 99.9% |
| Lovex D073.6 | <<locked>> | 80% | 42,569 psi | 67% | 2792 fps | 99.4% |
| Lovex S060 | <<locked>> | 80% | 43,294 psi | 68% | 2743 fps | 97.3% |
| Lovex S062 | <<locked>> | 80% | 38,914 psi | 61% | 2697 fps | 97.5% |
| Lovex S065 | <<locked>> | 92% | 45,992 psi | 72% | 2825 fps | 95.1% |
| Lovex S070 | <<locked>> | 98% | 52,417 psi | 82% | 2956 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 42,888 psi | 67% | 2769 fps | 98.4% |
| Norma 202 | <<locked>> | 80% | 42,699 psi | 67% | 2779 fps | 99.7% |
| Norma 203B | <<locked>> | 80% | 38,595 psi | 60% | 2723 fps | 96% |
| Norma URP | <<locked>> | 92% | 41,234 psi | 65% | 2815 fps | 95.3% |
| Ramshot Big Game | <<locked>> | 80% | 38,014 psi | 60% | 2726 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 98% | 48,805 psi | 76% | 2959 fps | 95.4% |
| Ramshot TAC | <<locked>> | 80% | 45,179 psi | 71% | 2808 fps | 95.1% |
| Ramshot Wild Boar | <<locked>> | 80% | 44,483 psi | 70% | 2831 fps | 97.6% |
| Ramshot X-Terminator | <<locked>> | 80% | 48,718 psi | 76% | 2861 fps | 98.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,832 psi | 42% | 1736 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 50,430 psi | 79% | 2907 fps | 99.9% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 51,285 psi | 80% | 2923 fps | 95.7% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 40,422 psi | 63% | 2828 fps | 95.9% |
| ReloadSwiss RS 60 | 77.5 gr | 80% | 33,692 psi | 53% | 2687 fps | 97.1% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 41,031 psi | 64% | 2831 fps | 95% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 47,065 psi | 74% | 2953 fps | 95.9% |
| Rottweil R 901 | <<locked>> | 80% | 47,036 psi | 74% | 2825 fps | 99.9% |
| Rottweil R 902 | <<locked>> | 80% | 40,973 psi | 64% | 2720 fps | 97.9% |
| Rottweil R 903 | <<locked>> | 80% | 34,476 psi | 54% | 2625 fps | 95.4% |
| Shooters World Long Rifle | <<locked>> | 92% | 45,992 psi | 72% | 2825 fps | 95.1% |
| Shooters World Match Rifle | <<locked>> | 80% | 42,569 psi | 67% | 2792 fps | 99.4% |
| Shooters World Precision | <<locked>> | 80% | 38,914 psi | 61% | 2697 fps | 97.5% |
| Shooters World SW4350 | <<locked>> | 98% | 52,417 psi | 82% | 2956 fps | 95.5% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 53,272 psi | 83% | 2920 fps | 99.5% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 37,289 psi | 58% | 2717 fps | 95.4% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 52,750 psi | 83% | 2913 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 43,671 psi | 68% | 2782 fps | 95.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 41,669 psi | 65% | 2766 fps | 96.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 43,845 psi | 69% | 2726 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 36,535 psi | 57% | 2585 fps | 99.5% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 51,822 psi | 81% | 2874 fps | 95% |
| Somchem S321 | <<locked>> | 80% | 48,907 psi | 77% | 2900 fps | 99.4% |
| Somchem S335 | <<locked>> | 80% | 43,671 psi | 68% | 2730 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 43,076 psi | 68% | 2779 fps | 97.2% |
| Somchem S355 | <<locked>> | 80% | 35,215 psi | 55% | 2628 fps | 95.4% |
| Somchem S365 | <<locked>> | 86% | 31,053 psi | 49% | 2602 fps | 95% |
| Vihtavuori N130 | <<locked>> | 80% | 49,240 psi | 77% | 2799 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 43,830 psi | 69% | 2723 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 39,856 psi | 62% | 2713 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 40,379 psi | 63% | 2707 fps | 99.7% |
| Vihtavuori N150 | <<locked>> | 80% | 33,417 psi | 52% | 2562 fps | 96.4% |
| Vihtavuori N160 | <<locked>> | 92% | 43,091 psi | 68% | 2815 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 45,208 psi | 71% | 2812 fps | 98.8% |
| Vihtavuori N540 | <<locked>> | 80% | 39,102 psi | 61% | 2694 fps | 99.2% |
| Vihtavuori N550 | <<locked>> | 92% | 42,656 psi | 67% | 2822 fps | 95.5% |
| Vihtavuori N555 | <<locked>> | 98% | 38,319 psi | 60% | 2795 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 36,100 psi | 57% | 2628 fps | 95.8% |
| Winchester 748 | <<locked>> | 80% | 44,585 psi | 70% | 2854 fps | 99.3% |
| Winchester 760 | <<locked>> | 98% | 53,287 psi | 84% | 3035 fps | 95.6% |
| Winchester StaBALL Match | <<locked>> | 80% | 41,205 psi | 65% | 2772 fps | 97.4% |
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 Rem. Ultra Mag. loaded with the .375 | 200gr | Impala LWHV LS. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,153 fps; across all powders the maximum-charge window runs from 1,890 fps to 3,153 fps. Accurate 4350 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 (440 MPa), the top charges use 55–90 %, leaving at least 10 % headroom. The 200.0 gr projectile in 0.375" calls for a 1:16.0 twist; slower twists will usually not stabilise this weight. Accurate 4350, Alliant Reloder-16, Alliant Reloder-23 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. Alliant Power Pro 2000-MR, ReloadSwiss RS 60, Alliant Reloder-17 rank at the top here: for .375 Rem. Ultra Mag. with the .375 | 200gr | Impala LWHV LS 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.