Load Specifications
Bullet:.375 | 300gr | Barnes X S
Bullet Manufacturer:Barnes
Bullet Weight:300 gr
Bullet Diameter:0.375"
Bullet Length:<<locked>>
Caliber:.375 Rem. Ultra Mag. load data
Case Length (l3):2.85"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:117 Grains of Water
Primer Size:Large Rifle Magnum (LRM)
Barrel Length:24"
Max. allowed Pressure:63,817 psi
Recommended Twist Rate:1:16.5
Load data in caliber .375 Rem. Ultra Mag. with .375 | 300gr | Barnes X S bullet and 103 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, ReloadSwiss RS 70 and Accurate High Country.
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 2495 | <<locked>> | 82% | 56,478 psi | 89% | 2434 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 56,028 psi | 88% | 2480 fps | 98.9% |
| Accurate 3100ᴾ | <<locked>> | 100% | 53,896 psi | 84% | 2526 fps | 99.7% |
| Accurate 4064 | <<locked>> | 84% | 56,492 psi | 89% | 2480 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 56,014 psi | 88% | 2569 fps | 100% |
| Accurate High Countryᴾ | <<locked>> | 100% | 57,725 psi | 90% | 2700 fps | 98.1% |
| Accurate MAGPROᴾ | <<locked>> | 100% | 54,882 psi | 86% | 2641 fps | 96.3% |
| ADI AR 2206H | <<locked>> | 82% | 57,566 psi | 90% | 2536 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 55,027 psi | 86% | 2497 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 56,072 psi | 88% | 2598 fps | 98.4% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 53,867 psi | 84% | 2592 fps | 96.9% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 57,595 psi | 90% | 2654 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 98% | 56,202 psi | 88% | 2598 fps | 98.5% |
| Alliant Power Pro Varmint | <<locked>> | 98% | 56,202 psi | 88% | 2598 fps | 98.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 56,072 psi | 88% | 2520 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 56,347 psi | 88% | 2539 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 55,796 psi | 87% | 2608 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 90% | 57,188 psi | 90% | 2635 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 55,419 psi | 87% | 2589 fps | 98.4% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 52,721 psi | 83% | 2595 fps | 98.2% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 50,053 psi | 78% | 2543 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 43,961 psi | 69% | 2477 fps | 99.2% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 57,101 psi | 89% | 2713 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 57,276 psi | 90% | 2552 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 48,602 psi | 76% | 2530 fps | 97.3% |
| Bofors RP3 | <<locked>> | 86% | 57,421 psi | 90% | 2539 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 52,721 psi | 83% | 2595 fps | 98.2% |
| Bofors RP7 | <<locked>> | 90% | 56,376 psi | 88% | 2523 fps | 99.1% |
| Hodgdon H380 | <<locked>> | 86% | 57,464 psi | 90% | 2552 fps | 100% |
| Hodgdon H414 | <<locked>> | 92% | 57,493 psi | 90% | 2608 fps | 99.6% |
| Hodgdon H4350 | <<locked>> | 90% | 57,305 psi | 90% | 2569 fps | 98.8% |
| Hodgdon H4831ᴾ | <<locked>> | 100% | 57,638 psi | 90% | 2592 fps | 97% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 56,434 psi | 88% | 2575 fps | 96.7% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 56,405 psi | 88% | 2543 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 54,824 psi | 86% | 2536 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 43,062 psi | 67% | 2500 fps | 96.5% |
| Hodgdon Superformance | <<locked>> | 92% | 57,609 psi | 90% | 2644 fps | 99.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,608 psi | 57% | 1552 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 55,535 psi | 87% | 2500 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 54,708 psi | 86% | 2484 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 57,174 psi | 90% | 2510 fps | 99.5% |
| IMR 4350 | <<locked>> | 94% | 56,695 psi | 89% | 2546 fps | 99.2% |
| IMR 4451 Enduron | <<locked>> | 90% | 57,479 psi | 90% | 2539 fps | 99.5% |
| IMR 4831 | <<locked>> | 94% | 56,202 psi | 88% | 2559 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 54,331 psi | 85% | 2520 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 55,666 psi | 87% | 2533 fps | 96.8% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 51,576 psi | 81% | 2569 fps | 96.5% |
| Lovex S060 | <<locked>> | 82% | 56,231 psi | 88% | 2467 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 55,405 psi | 87% | 2480 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 54,911 psi | 86% | 2500 fps | 99.8% |
| Lovex S070 | <<locked>> | 92% | 56,057 psi | 88% | 2536 fps | 99.5% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,368 psi | 71% | 2408 fps | 98.8% |
| Norma 201 | <<locked>> | 82% | 56,869 psi | 89% | 2490 fps | 100% |
| Norma 202 | <<locked>> | 82% | 57,232 psi | 90% | 2484 fps | 100% |
| Norma 203B | <<locked>> | 84% | 55,709 psi | 87% | 2530 fps | 100% |
| Norma 204 | <<locked>> | 94% | 57,508 psi | 90% | 2595 fps | 98.5% |
| Norma MRPᴾ | <<locked>> | 100% | 55,869 psi | 88% | 2671 fps | 99.5% |
| Norma URP | <<locked>> | 92% | 54,433 psi | 85% | 2556 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 56,057 psi | 88% | 2549 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 51,663 psi | 81% | 2579 fps | 96.9% |
| Ramshot Hunter | <<locked>> | 94% | 56,434 psi | 88% | 2602 fps | 99.8% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 46,354 psi | 73% | 2474 fps | 97.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,376 psi | 59% | 1591 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 57,145 psi | 90% | 2536 fps | 99.7% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 57,217 psi | 90% | 2598 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 56,826 psi | 89% | 2628 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 55,448 psi | 87% | 2589 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 57,305 psi | 90% | 2657 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,033 psi | 67% | 2497 fps | 97.6% |
| Rottweil R 902 | <<locked>> | 84% | 57,406 psi | 90% | 2487 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 57,421 psi | 90% | 2533 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 54,636 psi | 86% | 2526 fps | 97.2% |
| Rottweil R 905 | <<locked>> | 98% | 54,926 psi | 86% | 2582 fps | 98.5% |
| Rottweil R 907 | <<locked>> | 90% | 56,376 psi | 88% | 2523 fps | 99.1% |
| Shooters World Long Rifle | <<locked>> | 90% | 54,911 psi | 86% | 2500 fps | 99.8% |
| Shooters World Precision | <<locked>> | 84% | 55,405 psi | 87% | 2480 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 56,057 psi | 88% | 2536 fps | 99.5% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 54,665 psi | 86% | 2536 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 55,927 psi | 88% | 2513 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 57,174 psi | 90% | 2418 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 54,491 psi | 85% | 2382 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 54,433 psi | 85% | 2454 fps | 99.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 54,433 psi | 85% | 2575 fps | 98.4% |
| Somchem S335 | <<locked>> | 82% | 57,130 psi | 90% | 2421 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 57,087 psi | 89% | 2526 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 56,478 psi | 89% | 2520 fps | 96.7% |
| Somchem S365 | <<locked>> | 96% | 56,884 psi | 89% | 2598 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 55,709 psi | 87% | 2559 fps | 99.1% |
| Vihtavuori N133 | <<locked>> | 82% | 57,522 psi | 90% | 2402 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 57,609 psi | 90% | 2448 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 57,580 psi | 90% | 2461 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 54,868 psi | 86% | 2461 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 56,318 psi | 88% | 2543 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 51,343 psi | 80% | 2487 fps | 98.2% |
| Vihtavuori N540 | <<locked>> | 84% | 55,825 psi | 87% | 2464 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 55,651 psi | 87% | 2556 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 56,043 psi | 88% | 2608 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 56,217 psi | 88% | 2657 fps | 97.2% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 55,695 psi | 87% | 2513 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 57,682 psi | 90% | 2612 fps | 99.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 45,382 psi | 71% | 2595 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 56,144 psi | 88% | 2523 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 55,608 psi | 87% | 2549 fps | 98.3% |
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 2495 | <<locked>> | 80% | 53,055 psi | 83% | 2392 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 49,472 psi | 78% | 2388 fps | 98% |
| Accurate 3100 | <<locked>> | 84% | 32,663 psi | 51% | 2169 fps | 95.4% |
| Accurate 4064 | <<locked>> | 80% | 50,169 psi | 79% | 2402 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,363 psi | 60% | 2297 fps | 98.7% |
| Accurate High Country | 84.5 gr | 92% | 44,440 psi | 70% | 2493 fps | 95.3% |
| Accurate MAGPRO | <<locked>> | 98% | 51,285 psi | 80% | 2589 fps | 95.5% |
| ADI AR 2206H | <<locked>> | 80% | 54,302 psi | 85% | 2493 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 46,253 psi | 72% | 2369 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 88% | 41,379 psi | 65% | 2359 fps | 95.1% |
| ADI AR 2213 | <<locked>> | 96% | 47,601 psi | 75% | 2490 fps | 95.3% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 50,546 psi | 79% | 2556 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 41,437 psi | 65% | 2362 fps | 95.3% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 41,437 psi | 65% | 2362 fps | 95.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 46,905 psi | 74% | 2395 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,067 psi | 78% | 2454 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,767 psi | 58% | 2293 fps | 98.6% |
| Alliant Reloder-17 | <<locked>> | 80% | 41,292 psi | 65% | 2402 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 41,046 psi | 64% | 2356 fps | 95.2% |
| Alliant Reloder-22 | <<locked>> | 92% | 41,220 psi | 65% | 2402 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,818 psi | 44% | 2103 fps | 97.1% |
| Alliant Reloder-25 | <<locked>> | 90% | 32,866 psi | 52% | 2241 fps | 95.9% |
| Alliant Reloder-26 | 75.7 gr | 80% | 29,530 psi | 46% | 2198 fps | 95.3% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 53,708 psi | 84% | 2507 fps | 100% |
| Bofors RP15 | <<locked>> | 94% | 40,669 psi | 64% | 2388 fps | 95.1% |
| Bofors RP3 | <<locked>> | 80% | 47,616 psi | 75% | 2408 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 41,220 psi | 65% | 2402 fps | 95.5% |
| Bofors RP7 | <<locked>> | 80% | 42,047 psi | 66% | 2297 fps | 96.6% |
| Hodgdon H380 | <<locked>> | 80% | 47,718 psi | 75% | 2415 fps | 99.6% |
| Hodgdon H414 | <<locked>> | 80% | 39,566 psi | 62% | 2326 fps | 96.6% |
| Hodgdon H4350 | <<locked>> | 80% | 42,293 psi | 66% | 2336 fps | 95.9% |
| Hodgdon H4831 | <<locked>> | 96% | 50,676 psi | 79% | 2493 fps | 95.5% |
| Hodgdon H4831 SC | <<locked>> | 96% | 49,792 psi | 78% | 2480 fps | 95.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,577 psi | 54% | 2208 fps | 99.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 51,329 psi | 80% | 2490 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 40,683 psi | 64% | 2451 fps | 95.6% |
| Hodgdon Superformance | <<locked>> | 80% | 38,464 psi | 60% | 2333 fps | 95.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,514 psi | 43% | 1388 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 52,214 psi | 82% | 2457 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 48,617 psi | 76% | 2395 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 50,792 psi | 80% | 2421 fps | 98.8% |
| IMR 4350 | <<locked>> | 80% | 37,492 psi | 59% | 2234 fps | 95.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 42,917 psi | 67% | 2316 fps | 97.3% |
| IMR 4831 | <<locked>> | 80% | 36,651 psi | 57% | 2251 fps | 98.4% |
| IMR 4895 | <<locked>> | 80% | 51,271 psi | 80% | 2477 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 49,458 psi | 78% | 2444 fps | 95.5% |
| IMR 7828 SSC | <<locked>> | 98% | 48,399 psi | 76% | 2516 fps | 95.7% |
| Lovex S060 | <<locked>> | 80% | 53,127 psi | 83% | 2425 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,327 psi | 77% | 2402 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,031 psi | 64% | 2283 fps | 98.1% |
| Lovex S070 | <<locked>> | 80% | 39,378 psi | 62% | 2270 fps | 96.7% |
| Lovex S071 | <<locked>> | 88% | 31,908 psi | 50% | 2152 fps | 95.1% |
| Norma 201 | <<locked>> | 80% | 53,505 psi | 84% | 2448 fps | 100% |
| Norma 202 | <<locked>> | 80% | 53,824 psi | 84% | 2441 fps | 100% |
| Norma 203B | <<locked>> | 80% | 49,458 psi | 78% | 2444 fps | 100% |
| Norma 204 | <<locked>> | 84% | 41,756 psi | 65% | 2349 fps | 95.2% |
| Norma MRP | <<locked>> | 86% | 35,708 psi | 56% | 2316 fps | 95.1% |
| Norma URP | <<locked>> | 80% | 37,652 psi | 59% | 2287 fps | 98.5% |
| Ramshot Big Game | <<locked>> | 80% | 49,356 psi | 77% | 2457 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 45,281 psi | 71% | 2474 fps | 95.1% |
| Ramshot Hunter | <<locked>> | 80% | 36,506 psi | 57% | 2274 fps | 96.6% |
| Ramshot Magnum | <<locked>> | 96% | 40,538 psi | 64% | 2372 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,152 psi | 44% | 1424 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 47,514 psi | 74% | 2398 fps | 98.8% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 53,679 psi | 84% | 2552 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 43,671 psi | 68% | 2444 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,507 psi | 59% | 2306 fps | 98.3% |
| ReloadSwiss RS 70 | 75 gr | 80% | 36,492 psi | 57% | 2310 fps | 97.7% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 37,840 psi | 59% | 2385 fps | 95.6% |
| Rottweil R 902 | <<locked>> | 80% | 51,300 psi | 80% | 2411 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 44,991 psi | 71% | 2362 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 45,600 psi | 71% | 2388 fps | 95.1% |
| Rottweil R 905 | <<locked>> | 88% | 40,118 psi | 63% | 2343 fps | 95.2% |
| Rottweil R 907 | <<locked>> | 80% | 42,047 psi | 66% | 2297 fps | 96.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,031 psi | 64% | 2283 fps | 98.1% |
| Shooters World Precision | <<locked>> | 80% | 49,327 psi | 77% | 2402 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 39,378 psi | 62% | 2270 fps | 96.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,440 psi | 71% | 2405 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 52,678 psi | 83% | 2470 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 54,027 psi | 85% | 2382 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 45,861 psi | 72% | 2274 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,205 psi | 63% | 2234 fps | 96.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 39,755 psi | 62% | 2339 fps | 95% |
| Somchem S335 | <<locked>> | 80% | 53,809 psi | 84% | 2382 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 45,107 psi | 71% | 2359 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 49,719 psi | 78% | 2425 fps | 95.2% |
| Somchem S365 | <<locked>> | 80% | 34,287 psi | 54% | 2254 fps | 99.9% |
| Somchem S385 | <<locked>> | 86% | 38,696 psi | 61% | 2287 fps | 95.7% |
| Vihtavuori N133 | <<locked>> | 80% | 54,433 psi | 85% | 2365 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 51,285 psi | 80% | 2372 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 51,068 psi | 80% | 2382 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,047 psi | 67% | 2297 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 38,972 psi | 61% | 2280 fps | 98.7% |
| Vihtavuori N165 | <<locked>> | 92% | 40,103 psi | 63% | 2306 fps | 95.6% |
| Vihtavuori N540 | <<locked>> | 80% | 49,443 psi | 77% | 2382 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,609 psi | 61% | 2287 fps | 98.5% |
| Vihtavuori N555 | <<locked>> | 80% | 30,501 psi | 48% | 2172 fps | 97.2% |
| Vihtavuori N560 | <<locked>> | 96% | 49,429 psi | 77% | 2556 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 37,971 psi | 60% | 2251 fps | 99.8% |
| Winchester 760 | <<locked>> | 80% | 39,726 psi | 62% | 2329 fps | 96.7% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,990 psi | 39% | 2090 fps | 96.1% |
| Winchester StaBALL Match | <<locked>> | 80% | 52,663 psi | 83% | 2477 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 42,844 psi | 67% | 2359 fps | 95.7% |
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 103 powders for .375 Rem. Ultra Mag. loaded with the .375 | 300gr | Barnes X S. Alliant Reloder-26 delivers the highest muzzle velocity at 2,713 fps; across all powders the maximum-charge window runs from 1,552 fps to 2,713 fps. Accurate 3100 gives the best case fill at 100 %, and 103 of the 103 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.375" calls for a 1:16.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate High Country, Accurate MAGPRO 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 Reloder-26, ReloadSwiss RS 70, Accurate High Country rank at the top here: for .375 Rem. Ultra Mag. with the .375 | 300gr | Barnes X S 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.