Load Specifications
Load data in caliber .375 Ruger with .375 | 285gr | Speer Grand Slam bullet and 98 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, Hodgdon Superformance 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.
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You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 23"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 84% | 54,505 psi | 88% | 2405 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 53,026 psi | 85% | 2425 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 54,708 psi | 88% | 2480 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 55,782 psi | 90% | 2467 fps | 97.3% |
| Accurate 3100ᴾ | <<locked>> | 100% | 40,016 psi | 64% | 2326 fps | 95.8% |
| Accurate 4064 | <<locked>> | 90% | 52,953 psi | 85% | 2467 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 52,431 psi | 84% | 2536 fps | 99.6% |
| ADI AR 2206H | <<locked>> | 86% | 53,548 psi | 86% | 2493 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 54,534 psi | 88% | 2493 fps | 99.8% |
| ADI Benchmark 8208 | <<locked>> | 86% | 55,970 psi | 90% | 2493 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 53,287 psi | 86% | 2428 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 52,968 psi | 85% | 2595 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 54,346 psi | 88% | 2510 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 54,911 psi | 88% | 2530 fps | 99.9% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 53,795 psi | 87% | 2585 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 96% | 55,071 psi | 89% | 2618 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 38,522 psi | 62% | 2356 fps | 98.8% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 42,757 psi | 69% | 2490 fps | 98% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 53,142 psi | 86% | 2503 fps | 99.6% |
| Bofors RP3 | <<locked>> | 92% | 55,013 psi | 89% | 2526 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 55,071 psi | 89% | 2497 fps | 97.5% |
| Hodgdon Benchmark | <<locked>> | 84% | 54,259 psi | 87% | 2434 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 55,332 psi | 89% | 2520 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 53,592 psi | 86% | 2559 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 92% | 56,101 psi | 90% | 2539 fps | 99.6% |
| Hodgdon H414 | <<locked>> | 98% | 55,390 psi | 89% | 2579 fps | 98.2% |
| Hodgdon H4350 | <<locked>> | 96% | 56,115 psi | 90% | 2546 fps | 97.1% |
| Hodgdon H4895 | <<locked>> | 86% | 54,041 psi | 87% | 2503 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 50,009 psi | 81% | 2474 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 53,200 psi | 86% | 2530 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 52,388 psi | 84% | 2559 fps | 97.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,433 psi | 57% | 1519 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 55,172 psi | 89% | 2503 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 53,867 psi | 87% | 2484 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 54,099 psi | 87% | 2477 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 88% | 53,969 psi | 87% | 2457 fps | 97.8% |
| IMR 4350ᴾ | <<locked>> | 100% | 55,187 psi | 89% | 2516 fps | 97.6% |
| IMR 4451 Enduron | <<locked>> | 94% | 53,751 psi | 87% | 2480 fps | 97.7% |
| IMR 4831ᴾ | <<locked>> | 100% | 53,084 psi | 86% | 2530 fps | 99.6% |
| IMR 4895 | <<locked>> | 88% | 53,055 psi | 85% | 2513 fps | 100% |
| IMR 8208 XBR | <<locked>> | 86% | 55,970 psi | 90% | 2493 fps | 100% |
| Lovex D073.5 | <<locked>> | 82% | 56,144 psi | 90% | 2477 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 53,011 psi | 85% | 2470 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 53,272 psi | 86% | 2431 fps | 99.9% |
| Lovex S062 | <<locked>> | 90% | 53,766 psi | 87% | 2474 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 52,997 psi | 85% | 2474 fps | 98.8% |
| Lovex S070 | <<locked>> | 98% | 53,867 psi | 87% | 2507 fps | 98.1% |
| Norma 201 | <<locked>> | 88% | 55,724 psi | 90% | 2490 fps | 100% |
| Norma 202 | <<locked>> | 88% | 56,101 psi | 90% | 2487 fps | 100% |
| Norma 203B | <<locked>> | 90% | 54,157 psi | 87% | 2520 fps | 100% |
| Norma 204ᴾ | <<locked>> | 100% | 55,970 psi | 90% | 2562 fps | 96.5% |
| Norma URPᴾ | <<locked>> | 100% | 55,056 psi | 89% | 2572 fps | 99.7% |
| Ramshot Big Game | <<locked>> | 90% | 54,621 psi | 88% | 2539 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 53,838 psi | 87% | 2566 fps | 98.7% |
| Ramshot TAC | <<locked>> | 84% | 52,794 psi | 85% | 2464 fps | 98.8% |
| Ramshot Wild Boar | <<locked>> | 86% | 55,854 psi | 90% | 2526 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 53,388 psi | 86% | 2451 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,868 psi | 58% | 1555 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 55,347 psi | 89% | 2474 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 52,881 psi | 85% | 2474 fps | 98.2% |
| ReloadSwiss RS 52 | <<locked>> | 88% | 55,405 psi | 89% | 2589 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 94% | 54,926 psi | 88% | 2618 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 55,709 psi | 90% | 2602 fps | 99.7% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 55,622 psi | 90% | 2628 fps | 99.6% |
| Rottweil R 901 | <<locked>> | 84% | 53,316 psi | 86% | 2428 fps | 100% |
| Rottweil R 902 | <<locked>> | 90% | 56,130 psi | 90% | 2487 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 54,882 psi | 88% | 2516 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 55,071 psi | 89% | 2497 fps | 97.5% |
| Shooters World Long Rifle | <<locked>> | 96% | 52,997 psi | 85% | 2474 fps | 98.8% |
| Shooters World Match Rifle | <<locked>> | 86% | 53,011 psi | 85% | 2470 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 53,766 psi | 87% | 2474 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 53,867 psi | 87% | 2507 fps | 98.1% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 52,910 psi | 85% | 2526 fps | 99.9% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 54,708 psi | 88% | 2493 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 55,303 psi | 89% | 2513 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 53,824 psi | 87% | 2392 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 54,041 psi | 87% | 2392 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 53,272 psi | 86% | 2434 fps | 97.7% |
| Somchem S321 | <<locked>> | 82% | 53,490 psi | 86% | 2477 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 53,214 psi | 86% | 2392 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 54,201 psi | 87% | 2484 fps | 100% |
| Somchem S355 | <<locked>> | 94% | 55,201 psi | 89% | 2516 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 49,356 psi | 80% | 2526 fps | 100% |
| Vihtavuori N130 | <<locked>> | 82% | 53,737 psi | 87% | 2359 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 54,041 psi | 87% | 2379 fps | 100% |
| Vihtavuori N135 | <<locked>> | 90% | 55,796 psi | 90% | 2451 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 53,243 psi | 86% | 2428 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 53,214 psi | 86% | 2454 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 54,157 psi | 87% | 2523 fps | 99.6% |
| Vihtavuori N530 | <<locked>> | 84% | 52,852 psi | 85% | 2448 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 54,940 psi | 89% | 2467 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 53,243 psi | 86% | 2526 fps | 99.4% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 41,901 psi | 68% | 2421 fps | 98.7% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 54,476 psi | 88% | 2503 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 52,750 psi | 85% | 2490 fps | 100% |
| Winchester 760 | <<locked>> | 98% | 55,593 psi | 90% | 2582 fps | 98.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 34,389 psi | 55% | 2352 fps | 98.6% |
| Winchester StaBALL Match | <<locked>> | 88% | 55,216 psi | 89% | 2520 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 23"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 80% | 48,196 psi | 78% | 2326 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 40,770 psi | 66% | 2260 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 47,747 psi | 77% | 2392 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 45,905 psi | 74% | 2326 fps | 95.2% |
| Accurate 3100 | <<locked>> | 98% | 37,289 psi | 60% | 2277 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 38,537 psi | 62% | 2257 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 32,242 psi | 52% | 2192 fps | 95.1% |
| ADI AR 2206H | <<locked>> | 80% | 44,324 psi | 71% | 2356 fps | 99.3% |
| ADI AR 2208 | <<locked>> | 80% | 37,768 psi | 61% | 2224 fps | 97.5% |
| ADI Benchmark 8208 | <<locked>> | 80% | 46,412 psi | 75% | 2362 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 80% | 46,528 psi | 75% | 2346 fps | 100% |
| Alliant Power Pro 2000-MR | 66.8 gr | 80% | 40,248 psi | 65% | 2382 fps | 98% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 37,347 psi | 60% | 2247 fps | 98.8% |
| Alliant Reloder-15 | <<locked>> | 80% | 40,074 psi | 65% | 2300 fps | 98.2% |
| Alliant Reloder-16 | <<locked>> | 84% | 32,851 psi | 53% | 2205 fps | 95.2% |
| Alliant Reloder-17 | 65.8 gr | 80% | 32,213 psi | 52% | 2218 fps | 96.9% |
| Alliant Reloder-23 | <<locked>> | 92% | 30,095 psi | 48% | 2165 fps | 95.8% |
| Alliant Reloder-26 | <<locked>> | 94% | 34,766 psi | 56% | 2323 fps | 95.2% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 43,555 psi | 70% | 2359 fps | 98.4% |
| Bofors RP3 | <<locked>> | 80% | 36,927 psi | 59% | 2251 fps | 98.8% |
| Bofors RP7 | <<locked>> | 90% | 45,730 psi | 74% | 2359 fps | 95.5% |
| Hodgdon Benchmark | <<locked>> | 80% | 48,022 psi | 77% | 2349 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 45,208 psi | 73% | 2382 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 49,763 psi | 80% | 2507 fps | 99.6% |
| Hodgdon H380 | <<locked>> | 80% | 37,811 psi | 61% | 2251 fps | 96.4% |
| Hodgdon H414 | <<locked>> | 90% | 42,540 psi | 69% | 2385 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 92% | 49,530 psi | 80% | 2451 fps | 95.7% |
| Hodgdon H4895 | <<locked>> | 80% | 44,730 psi | 72% | 2365 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 28,311 psi | 46% | 2070 fps | 95.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 40,683 psi | 66% | 2339 fps | 99.4% |
| Hodgdon Superformance | 79.9 gr | 92% | 45,411 psi | 73% | 2451 fps | 95.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,353 psi | 42% | 1358 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 42,917 psi | 69% | 2323 fps | 99.4% |
| IMR 3031 | <<locked>> | 80% | 44,396 psi | 72% | 2359 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 39,639 psi | 64% | 2254 fps | 98.2% |
| IMR 4166 Enduron | <<locked>> | 80% | 42,047 psi | 68% | 2270 fps | 95.1% |
| IMR 4350 | <<locked>> | 94% | 45,905 psi | 74% | 2382 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 86% | 42,076 psi | 68% | 2297 fps | 95% |
| IMR 4831 | <<locked>> | 86% | 33,620 psi | 54% | 2205 fps | 95.7% |
| IMR 4895 | <<locked>> | 80% | 41,031 psi | 66% | 2326 fps | 98.9% |
| IMR 8208 XBR | <<locked>> | 80% | 46,412 psi | 75% | 2362 fps | 99.9% |
| Lovex D073.5 | <<locked>> | 80% | 52,620 psi | 85% | 2434 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 43,439 psi | 70% | 2339 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 44,396 psi | 72% | 2300 fps | 99.3% |
| Lovex S062 | <<locked>> | 80% | 39,494 psi | 64% | 2257 fps | 99.4% |
| Lovex S065 | <<locked>> | 84% | 36,709 psi | 59% | 2205 fps | 95% |
| Lovex S070 | <<locked>> | 90% | 42,018 psi | 68% | 2323 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 43,395 psi | 70% | 2313 fps | 99.8% |
| Norma 202 | <<locked>> | 80% | 43,743 psi | 70% | 2323 fps | 100% |
| Norma 203B | <<locked>> | 80% | 39,436 psi | 64% | 2290 fps | 98.5% |
| Norma 204 | <<locked>> | 98% | 52,388 psi | 84% | 2513 fps | 95.7% |
| Norma URP | <<locked>> | 84% | 32,764 psi | 53% | 2195 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 80% | 38,943 psi | 63% | 2300 fps | 98.3% |
| Ramshot Hunter | <<locked>> | 90% | 38,899 psi | 63% | 2323 fps | 95.3% |
| Ramshot TAC | <<locked>> | 80% | 46,282 psi | 75% | 2369 fps | 97.8% |
| Ramshot Wild Boar | <<locked>> | 80% | 45,788 psi | 74% | 2385 fps | 99.4% |
| Ramshot X-Terminator | <<locked>> | 80% | 49,951 psi | 80% | 2402 fps | 99.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,658 psi | 43% | 1391 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 51,938 psi | 84% | 2431 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 40,698 psi | 66% | 2280 fps | 95.5% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 41,945 psi | 68% | 2388 fps | 98.6% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 34,287 psi | 55% | 2277 fps | 99.5% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 34,374 psi | 55% | 2254 fps | 95.5% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 37,101 psi | 60% | 2313 fps | 95.6% |
| Rottweil R 901 | <<locked>> | 80% | 47,485 psi | 76% | 2349 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 41,249 psi | 66% | 2270 fps | 99.5% |
| Rottweil R 903 | <<locked>> | 80% | 34,693 psi | 56% | 2198 fps | 98% |
| Rottweil R 907 | <<locked>> | 90% | 45,730 psi | 74% | 2359 fps | 95.5% |
| Shooters World Long Rifle | <<locked>> | 84% | 36,709 psi | 59% | 2205 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 43,439 psi | 70% | 2339 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 39,494 psi | 64% | 2257 fps | 99.4% |
| Shooters World SW4350 | <<locked>> | 90% | 42,018 psi | 68% | 2323 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 35,607 psi | 57% | 2241 fps | 97.5% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 44,657 psi | 72% | 2346 fps | 98% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 42,728 psi | 69% | 2329 fps | 99% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 44,831 psi | 72% | 2270 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 37,260 psi | 60% | 2156 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 43,816 psi | 71% | 2293 fps | 95.7% |
| Somchem S321 | <<locked>> | 80% | 50,212 psi | 81% | 2431 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 44,324 psi | 71% | 2270 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 44,353 psi | 71% | 2343 fps | 99.2% |
| Somchem S355 | <<locked>> | 80% | 35,563 psi | 57% | 2205 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 25,875 psi | 42% | 2057 fps | 95.6% |
| Vihtavuori N130 | <<locked>> | 80% | 50,560 psi | 81% | 2320 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 45,121 psi | 73% | 2264 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 40,799 psi | 66% | 2257 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 41,336 psi | 67% | 2264 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 33,823 psi | 54% | 2149 fps | 98.7% |
| Vihtavuori N160 | <<locked>> | 84% | 34,243 psi | 55% | 2198 fps | 95.6% |
| Vihtavuori N530 | <<locked>> | 80% | 46,485 psi | 75% | 2359 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 80% | 39,914 psi | 64% | 2257 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 33,736 psi | 54% | 2198 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 90% | 30,211 psi | 49% | 2185 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 30,081 psi | 48% | 2083 fps | 96.2% |
| Winchester 748 | <<locked>> | 80% | 46,050 psi | 74% | 2398 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 42,540 psi | 69% | 2385 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 94% | 28,442 psi | 46% | 2182 fps | 95.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 42,235 psi | 68% | 2333 fps | 99.4% |
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 114 powders for .375 Ruger loaded with the .375 | 285gr | Speer Grand Slam. ReloadSwiss RS 70 delivers the highest muzzle velocity at 2,628 fps; across all powders the maximum-charge window runs from 1,519 fps to 2,628 fps. Accurate 3100 gives the best case fill at 100 %, and 114 of the 114 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (428 MPa), the top charges use 53–90 %, leaving at least 10 % headroom. The 285.0 gr projectile in 0.375" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, Alliant Reloder-16 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, Hodgdon Superformance, Alliant Reloder-17 rank at the top here: for .375 Ruger with the .375 | 285gr | Speer Grand Slam they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2209, Alliant Reloder-19, Alliant Reloder-22 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.