Load Specifications
Load data in caliber .375 H&H Mag. with .374 | 270gr | Rhino Penetrator bullet and 96 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 CFE223 and Ramshot Big Game.
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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 90% | 55,637 psi | 89% | 2507 fps | 100% |
| Accurate 2200 | <<locked>> | 82% | 55,840 psi | 90% | 2595 fps | 99.2% |
| Accurate 2460 | <<locked>> | 86% | 53,954 psi | 87% | 2530 fps | 100% |
| Accurate 2495 | <<locked>> | 96% | 56,188 psi | 90% | 2566 fps | 100% |
| Accurate 2520 | <<locked>> | 90% | 55,564 psi | 89% | 2589 fps | 100% |
| Accurate 4064 | <<locked>> | 98% | 55,477 psi | 89% | 2598 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 44,121 psi | 71% | 2503 fps | 97.1% |
| Accurate LT-30 | <<locked>> | 84% | 55,506 psi | 89% | 2457 fps | 100% |
| Accurate LT-32 | <<locked>> | 84% | 55,970 psi | 90% | 2480 fps | 100% |
| ADI AR 2206H | <<locked>> | 92% | 54,404 psi | 87% | 2589 fps | 99.5% |
| ADI AR 2208 | <<locked>> | 98% | 55,245 psi | 89% | 2582 fps | 99.2% |
| ADI AR 2219 | <<locked>> | 84% | 55,985 psi | 90% | 2569 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 90% | 53,795 psi | 86% | 2549 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 90% | 53,519 psi | 86% | 2533 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 86% | 55,390 psi | 89% | 2648 fps | 99.8% |
| Alliant Power Pro 2000-MR | <<locked>> | 94% | 53,592 psi | 86% | 2687 fps | 99.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 98% | 54,346 psi | 87% | 2602 fps | 99.9% |
| Alliant Reloder-10x | <<locked>> | 86% | 55,521 psi | 89% | 2513 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 96% | 55,288 psi | 89% | 2621 fps | 99.3% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 44,672 psi | 72% | 2513 fps | 97.2% |
| Alliant Reloder-17ᴾ | <<locked>> | 100% | 51,430 psi | 82% | 2657 fps | 99.6% |
| Baschieri & Pellagri 106 | <<locked>> | 84% | 54,592 psi | 88% | 2457 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 92% | 53,940 psi | 86% | 2598 fps | 98.8% |
| Bofors RP3 | <<locked>> | 98% | 54,737 psi | 88% | 2618 fps | 99.9% |
| Hodgdon Benchmark | <<locked>> | 90% | 56,231 psi | 90% | 2539 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 92% | 55,883 psi | 90% | 2625 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 88% | 54,143 psi | 87% | 2661 fps | 99.3% |
| Hodgdon H322 | <<locked>> | 86% | 54,491 psi | 87% | 2549 fps | 100% |
| Hodgdon H335 | <<locked>> | 86% | 55,564 psi | 89% | 2575 fps | 100% |
| Hodgdon H380 | <<locked>> | 98% | 56,376 psi | 90% | 2625 fps | 98.6% |
| Hodgdon H4895 | <<locked>> | 92% | 54,839 psi | 88% | 2598 fps | 99.8% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 40,915 psi | 66% | 2411 fps | 97.9% |
| Hodgdon LEVERevolution | <<locked>> | 94% | 53,359 psi | 86% | 2628 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,664 psi | 56% | 1526 fps | 100% |
| Hodgdon VARGET | <<locked>> | 94% | 56,333 psi | 90% | 2602 fps | 99.8% |
| IMR 3031 | <<locked>> | 92% | 53,896 psi | 86% | 2585 fps | 100% |
| IMR 4064 | <<locked>> | 96% | 54,940 psi | 88% | 2569 fps | 99.3% |
| IMR 4166 Enduron | <<locked>> | 94% | 55,854 psi | 90% | 2549 fps | 96.4% |
| IMR 4198 | <<locked>> | 86% | 56,072 psi | 90% | 2477 fps | 100% |
| IMR 4451 Enduronᴾ | <<locked>> | 100% | 54,563 psi | 87% | 2562 fps | 96.1% |
| IMR 4831ᴾ | <<locked>> | 100% | 42,496 psi | 68% | 2457 fps | 96.7% |
| IMR 4895 | <<locked>> | 94% | 53,185 psi | 85% | 2605 fps | 99.5% |
| IMR 8208 XBR | <<locked>> | 90% | 53,795 psi | 86% | 2549 fps | 99.9% |
| Lovex D073.5 | <<locked>> | 86% | 53,882 psi | 86% | 2539 fps | 100% |
| Lovex D073.6 | <<locked>> | 92% | 53,359 psi | 86% | 2572 fps | 100% |
| Lovex S060 | <<locked>> | 92% | 54,911 psi | 88% | 2526 fps | 99.5% |
| Lovex S062 | <<locked>> | 96% | 54,143 psi | 87% | 2569 fps | 99.9% |
| Lovex S065ᴾ | <<locked>> | 100% | 49,893 psi | 80% | 2507 fps | 96.7% |
| Norma 200 | <<locked>> | 82% | 55,390 psi | 89% | 2487 fps | 100% |
| Norma 201 | <<locked>> | 92% | 53,156 psi | 85% | 2543 fps | 99.9% |
| Norma 202 | <<locked>> | 92% | 53,577 psi | 86% | 2549 fps | 100% |
| Norma 203B | <<locked>> | 96% | 54,375 psi | 87% | 2612 fps | 99.5% |
| Norma URPᴾ | <<locked>> | 100% | 44,628 psi | 72% | 2503 fps | 97% |
| Ramshot Big Game | <<locked>> | 96% | 54,708 psi | 88% | 2635 fps | 99.5% |
| Ramshot TAC | <<locked>> | 90% | 54,476 psi | 87% | 2566 fps | 97.8% |
| Ramshot Wild Boar | <<locked>> | 90% | 53,229 psi | 85% | 2579 fps | 99.4% |
| Ramshot X-Terminator | <<locked>> | 88% | 55,245 psi | 89% | 2556 fps | 99.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 34,838 psi | 56% | 1562 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 86% | 53,635 psi | 86% | 2539 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 96% | 53,505 psi | 86% | 2559 fps | 96.7% |
| ReloadSwiss RS 52 | <<locked>> | 94% | 55,216 psi | 89% | 2684 fps | 99.4% |
| ReloadSwiss RS 60ᴾ | <<locked>> | 100% | 54,955 psi | 88% | 2717 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 44,164 psi | 71% | 2523 fps | 96.7% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 45,527 psi | 73% | 2539 fps | 96% |
| Rottweil R 901 | <<locked>> | 90% | 54,476 psi | 87% | 2530 fps | 100% |
| Rottweil R 902 | <<locked>> | 94% | 53,635 psi | 86% | 2539 fps | 99.9% |
| Rottweil R 903ᴾ | <<locked>> | 100% | 54,360 psi | 87% | 2605 fps | 99.8% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 49,893 psi | 80% | 2507 fps | 96.7% |
| Shooters World Match Rifle | <<locked>> | 92% | 53,359 psi | 86% | 2572 fps | 100% |
| Shooters World Precision | <<locked>> | 96% | 54,143 psi | 87% | 2569 fps | 99.9% |
| Shooters World Tactical Rifle | <<locked>> | 84% | 53,679 psi | 86% | 2513 fps | 99.8% |
| SNPE Vectan BA6 1/2 | <<locked>> | 82% | 56,217 psi | 90% | 2231 fps | 100% |
| SNPE Vectan SP 10 | <<locked>> | 84% | 56,318 psi | 90% | 2579 fps | 100% |
| SNPE Vectan SP 11ᴾ | <<locked>> | 100% | 56,260 psi | 90% | 2661 fps | 99.6% |
| SNPE Vectan SP 3 | <<locked>> | 84% | 53,171 psi | 85% | 2490 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 92% | 55,869 psi | 90% | 2589 fps | 98.4% |
| SNPE Vectan SP 9 | <<locked>> | 94% | 56,304 psi | 90% | 2612 fps | 99.6% |
| SNPE Vectan Tubal 3000 | <<locked>> | 92% | 55,492 psi | 89% | 2493 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 98% | 54,911 psi | 88% | 2487 fps | 100% |
| Somchem S321 | <<locked>> | 88% | 54,984 psi | 88% | 2585 fps | 100% |
| Somchem S335 | <<locked>> | 92% | 54,404 psi | 87% | 2493 fps | 100% |
| Somchem S341 | <<locked>> | 92% | 55,172 psi | 88% | 2582 fps | 99.5% |
| Somchem S355ᴾ | <<locked>> | 100% | 54,998 psi | 88% | 2602 fps | 99.8% |
| Somchem S365ᴾ | <<locked>> | 100% | 39,726 psi | 64% | 2457 fps | 98.9% |
| Vihtavuori N130 | <<locked>> | 88% | 55,535 psi | 89% | 2467 fps | 100% |
| Vihtavuori N133 | <<locked>> | 92% | 55,347 psi | 89% | 2480 fps | 100% |
| Vihtavuori N135 | <<locked>> | 96% | 55,941 psi | 90% | 2552 fps | 100% |
| Vihtavuori N140 | <<locked>> | 94% | 53,925 psi | 86% | 2526 fps | 100% |
| Vihtavuori N150ᴾ | <<locked>> | 100% | 53,229 psi | 85% | 2543 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 46,949 psi | 75% | 2503 fps | 97.4% |
| Vihtavuori N530 | <<locked>> | 90% | 54,404 psi | 87% | 2552 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 96% | 55,492 psi | 89% | 2569 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 46,050 psi | 74% | 2510 fps | 97.1% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 48,312 psi | 77% | 2497 fps | 99.2% |
| Winchester 748 | <<locked>> | 90% | 53,476 psi | 86% | 2595 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 94% | 55,854 psi | 90% | 2618 fps | 99.8% |
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% | 40,944 psi | 66% | 2303 fps | 100% |
| Accurate 2200 | <<locked>> | 80% | 52,373 psi | 84% | 2546 fps | 98.8% |
| Accurate 2460 | <<locked>> | 80% | 44,266 psi | 71% | 2392 fps | 99.9% |
| Accurate 2495 | <<locked>> | 80% | 33,373 psi | 54% | 2221 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 39,378 psi | 63% | 2349 fps | 99.5% |
| Accurate 4064 | <<locked>> | 80% | 31,560 psi | 51% | 2205 fps | 98.8% |
| Accurate 4350 | <<locked>> | 96% | 38,421 psi | 62% | 2405 fps | 95.5% |
| Accurate LT-30 | <<locked>> | 80% | 49,226 psi | 79% | 2375 fps | 100% |
| Accurate LT-32 | <<locked>> | 80% | 49,617 psi | 80% | 2395 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 37,478 psi | 60% | 2303 fps | 96.6% |
| ADI AR 2208 | <<locked>> | 84% | 36,230 psi | 58% | 2264 fps | 95.3% |
| ADI AR 2219 | <<locked>> | 80% | 49,008 psi | 79% | 2477 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 80% | 39,494 psi | 63% | 2320 fps | 98.3% |
| Alliant AR-Comp | <<locked>> | 80% | 38,392 psi | 62% | 2326 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 45,556 psi | 73% | 2497 fps | 98.9% |
| Alliant Power Pro 2000-MR | 62.9 gr | 84% | 38,537 psi | 62% | 2415 fps | 95.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 30,908 psi | 50% | 2185 fps | 95.4% |
| Alliant Reloder-10x | <<locked>> | 80% | 46,267 psi | 74% | 2388 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 35,665 psi | 57% | 2287 fps | 95.4% |
| Alliant Reloder-16 | <<locked>> | 96% | 39,668 psi | 64% | 2415 fps | 95.7% |
| Alliant Reloder-17 | <<locked>> | 88% | 34,635 psi | 56% | 2339 fps | 95.8% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 48,153 psi | 77% | 2375 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 38,798 psi | 62% | 2352 fps | 95.7% |
| Bofors RP3 | <<locked>> | 80% | 30,095 psi | 48% | 2182 fps | 95.2% |
| Hodgdon Benchmark | <<locked>> | 80% | 41,539 psi | 67% | 2316 fps | 99% |
| Hodgdon BL-C2 | <<locked>> | 80% | 37,478 psi | 60% | 2333 fps | 98.4% |
| Hodgdon CFE223 | 61.3 gr | 80% | 41,133 psi | 66% | 2448 fps | 97.1% |
| Hodgdon H322 | <<locked>> | 80% | 44,846 psi | 72% | 2415 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 45,455 psi | 73% | 2434 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 40,770 psi | 65% | 2382 fps | 95.5% |
| Hodgdon H4895 | <<locked>> | 80% | 37,724 psi | 60% | 2316 fps | 97.3% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 33,997 psi | 55% | 2270 fps | 95.7% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 33,663 psi | 54% | 2280 fps | 96.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,628 psi | 41% | 1358 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 36,361 psi | 58% | 2274 fps | 96.8% |
| IMR 3031 | <<locked>> | 80% | 36,564 psi | 59% | 2323 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 35,650 psi | 57% | 2247 fps | 95.4% |
| IMR 4166 Enduron | <<locked>> | 90% | 49,197 psi | 79% | 2451 fps | 95% |
| IMR 4198 | <<locked>> | 80% | 47,007 psi | 75% | 2359 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 98% | 51,300 psi | 82% | 2516 fps | 95.4% |
| IMR 4831 | <<locked>> | 96% | 37,391 psi | 60% | 2362 fps | 95.2% |
| IMR 4895 | <<locked>> | 80% | 34,185 psi | 55% | 2267 fps | 95.6% |
| IMR 8208 XBR | <<locked>> | 80% | 39,494 psi | 63% | 2320 fps | 98.3% |
| Lovex D073.5 | <<locked>> | 80% | 44,005 psi | 71% | 2395 fps | 99.6% |
| Lovex D073.6 | <<locked>> | 80% | 35,694 psi | 57% | 2287 fps | 98.9% |
| Lovex S060 | <<locked>> | 80% | 38,392 psi | 62% | 2257 fps | 96.8% |
| Lovex S062 | <<locked>> | 80% | 33,199 psi | 53% | 2208 fps | 96.7% |
| Lovex S065 | <<locked>> | 96% | 44,295 psi | 71% | 2418 fps | 95.4% |
| Norma 200 | <<locked>> | 80% | 52,214 psi | 84% | 2448 fps | 100% |
| Norma 201 | <<locked>> | 80% | 36,811 psi | 59% | 2267 fps | 97.7% |
| Norma 202 | <<locked>> | 80% | 36,767 psi | 59% | 2283 fps | 99.4% |
| Norma 203B | <<locked>> | 80% | 32,822 psi | 53% | 2231 fps | 95% |
| Norma URP | <<locked>> | 96% | 39,305 psi | 63% | 2405 fps | 95.5% |
| Ramshot Big Game | 61.4 gr | 82% | 34,563 psi | 55% | 2287 fps | 95.3% |
| Ramshot TAC | <<locked>> | 82% | 41,959 psi | 67% | 2362 fps | 95% |
| Ramshot Wild Boar | <<locked>> | 80% | 38,247 psi | 61% | 2329 fps | 96.7% |
| Ramshot X-Terminator | <<locked>> | 80% | 42,772 psi | 69% | 2362 fps | 97.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,904 psi | 42% | 1394 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 44,280 psi | 71% | 2402 fps | 99.8% |
| ReloadSwiss RS 50 | <<locked>> | 92% | 47,094 psi | 76% | 2461 fps | 95.3% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 36,753 psi | 59% | 2372 fps | 95.7% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 28,543 psi | 46% | 2188 fps | 95.7% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 38,740 psi | 62% | 2421 fps | 95% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 42,598 psi | 68% | 2484 fps | 95% |
| Rottweil R 901 | <<locked>> | 80% | 40,567 psi | 65% | 2316 fps | 99.7% |
| Rottweil R 902 | <<locked>> | 80% | 35,056 psi | 56% | 2224 fps | 97.2% |
| Rottweil R 903 | <<locked>> | 84% | 32,387 psi | 52% | 2228 fps | 95.8% |
| Shooters World Long Rifle | <<locked>> | 96% | 44,295 psi | 71% | 2418 fps | 95.4% |
| Shooters World Match Rifle | <<locked>> | 80% | 35,694 psi | 57% | 2287 fps | 98.9% |
| Shooters World Precision | <<locked>> | 80% | 33,199 psi | 53% | 2208 fps | 96.7% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 46,862 psi | 75% | 2415 fps | 99.2% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 53,272 psi | 85% | 2198 fps | 100% |
| SNPE Vectan SP 10 | <<locked>> | 80% | 49,356 psi | 79% | 2487 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 33,649 psi | 54% | 2270 fps | 95% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 46,905 psi | 75% | 2405 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 39,827 psi | 64% | 2333 fps | 95% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 35,955 psi | 58% | 2274 fps | 96.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 38,406 psi | 62% | 2238 fps | 99.6% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 31,459 psi | 50% | 2119 fps | 99.1% |
| Somchem S321 | <<locked>> | 80% | 42,206 psi | 68% | 2392 fps | 99% |
| Somchem S335 | <<locked>> | 80% | 37,971 psi | 61% | 2244 fps | 99.8% |
| Somchem S341 | <<locked>> | 80% | 36,970 psi | 59% | 2290 fps | 96.3% |
| Somchem S355 | <<locked>> | 82% | 31,430 psi | 50% | 2188 fps | 95.1% |
| Somchem S365 | <<locked>> | 90% | 29,109 psi | 47% | 2211 fps | 95.2% |
| Vihtavuori N130 | <<locked>> | 80% | 43,569 psi | 70% | 2306 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 38,493 psi | 62% | 2241 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 33,765 psi | 54% | 2221 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 34,766 psi | 56% | 2224 fps | 99.3% |
| Vihtavuori N150 | <<locked>> | 80% | 27,978 psi | 45% | 2090 fps | 95.3% |
| Vihtavuori N160 | <<locked>> | 94% | 38,812 psi | 62% | 2359 fps | 95.2% |
| Vihtavuori N530 | <<locked>> | 80% | 39,305 psi | 63% | 2313 fps | 98.3% |
| Vihtavuori N540 | <<locked>> | 80% | 33,315 psi | 53% | 2211 fps | 98.7% |
| Vihtavuori N550 | <<locked>> | 96% | 40,422 psi | 65% | 2411 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 32,677 psi | 52% | 2201 fps | 95.1% |
| Winchester 748 | <<locked>> | 80% | 38,116 psi | 61% | 2349 fps | 98.8% |
| Winchester StaBALL Match | <<locked>> | 80% | 34,983 psi | 56% | 2274 fps | 96.5% |
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 96 powders for .375 H&H Mag. loaded with the .374 | 270gr | Rhino Penetrator. ReloadSwiss RS 60 delivers the highest muzzle velocity at 2,717 fps; across all powders the maximum-charge window runs from 1,526 fps to 2,717 fps. Accurate 4350 gives the best case fill at 100 %, and 96 of the 96 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (430 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 270.0 gr projectile in 0.374" calls for a 1:17.0 twist; slower twists will usually not stabilise this weight. Accurate 4350, Alliant Reloder-16, Alliant Reloder-17 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 CFE223, Ramshot Big Game rank at the top here: for .375 H&H Mag. with the .374 | 270gr | Rhino Penetrator 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.