Load Specifications
Load data in caliber .375 Fl. Mag. N.E. with .375 | 400gr | MAKER REX SUB bullet and 59 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-17, Alliant Reloder-26 and Alliant Reloder-16.
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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Max Load - Barrel Length: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 82% | 42,612 psi | 90% | 1877 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 42,554 psi | 90% | 1877 fps | 96.6% |
| Accurate 3100ᴾ | <<locked>> | 100% | 38,943 psi | 83% | 1929 fps | 97.7% |
| Accurate 4064 | <<locked>> | 82% | 40,292 psi | 85% | 1880 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 41,800 psi | 89% | 1975 fps | 99.5% |
| ADI AR 2208 | <<locked>> | 84% | 42,322 psi | 90% | 1903 fps | 99.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 41,974 psi | 89% | 1919 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 42,279 psi | 90% | 1929 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 92% | 41,524 psi | 88% | 1982 fps | 99.6% |
| Alliant Reloder-17 | <<locked>> | 88% | 41,466 psi | 88% | 2005 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 37,550 psi | 80% | 1952 fps | 99.8% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 33,185 psi | 70% | 1880 fps | 96.2% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 41,582 psi | 88% | 2073 fps | 99.4% |
| Bofors RP3 | <<locked>> | 84% | 41,553 psi | 88% | 1926 fps | 100% |
| Bofors RP7 | <<locked>> | 88% | 42,554 psi | 90% | 1909 fps | 96.9% |
| Hodgdon H380 | <<locked>> | 84% | 42,453 psi | 90% | 1932 fps | 99.2% |
| Hodgdon H414 | <<locked>> | 90% | 41,945 psi | 89% | 1975 fps | 97.5% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 40,872 psi | 87% | 1936 fps | 100% |
| Hodgdon Superformance | <<locked>> | 90% | 41,495 psi | 88% | 1991 fps | 96.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,433 psi | 75% | 1201 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 41,989 psi | 89% | 1890 fps | 99.7% |
| IMR 4350 | <<locked>> | 92% | 42,627 psi | 90% | 1932 fps | 97% |
| IMR 4451 Enduron | <<locked>> | 86% | 41,684 psi | 88% | 1896 fps | 97.1% |
| IMR 4831 | <<locked>> | 92% | 40,132 psi | 85% | 1936 fps | 99.3% |
| Lovex S062 | <<locked>> | 82% | 41,713 psi | 88% | 1890 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 40,944 psi | 87% | 1893 fps | 98.3% |
| Lovex S070 | <<locked>> | 90% | 41,350 psi | 88% | 1919 fps | 97.5% |
| Lovex S071ᴾ | <<locked>> | 100% | 32,300 psi | 69% | 1824 fps | 95.8% |
| Norma 203B | <<locked>> | 82% | 41,611 psi | 88% | 1923 fps | 99.9% |
| Norma MRPᴾ | <<locked>> | 100% | 41,887 psi | 89% | 2044 fps | 97.3% |
| Norma URP | <<locked>> | 92% | 41,945 psi | 89% | 1972 fps | 99.4% |
| Ramshot Big Game | <<locked>> | 82% | 41,321 psi | 88% | 1939 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 92% | 40,857 psi | 87% | 1969 fps | 98% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,897 psi | 76% | 1230 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 40,248 psi | 85% | 1883 fps | 97.5% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 41,350 psi | 88% | 2001 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 41,495 psi | 88% | 1995 fps | 99.3% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 41,727 psi | 89% | 2011 fps | 99% |
| Rottweil R 903 | <<locked>> | 86% | 41,698 psi | 88% | 1923 fps | 100% |
| Rottweil R 905 | <<locked>> | 98% | 41,843 psi | 89% | 1978 fps | 95.9% |
| Rottweil R 907 | <<locked>> | 88% | 42,554 psi | 90% | 1909 fps | 96.9% |
| Shooters World Long Rifle | <<locked>> | 88% | 40,944 psi | 87% | 1893 fps | 98.3% |
| Shooters World Precision | <<locked>> | 82% | 41,713 psi | 88% | 1890 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 41,350 psi | 88% | 1919 fps | 97.5% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 40,292 psi | 85% | 1929 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 42,032 psi | 89% | 1827 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 40,437 psi | 86% | 1857 fps | 97% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 41,495 psi | 88% | 1975 fps | 95.8% |
| Somchem S355 | <<locked>> | 86% | 42,467 psi | 90% | 1923 fps | 100% |
| Somchem S365 | <<locked>> | 96% | 42,540 psi | 90% | 2011 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 42,279 psi | 90% | 1965 fps | 96.9% |
| Vihtavuori N150 | <<locked>> | 86% | 40,669 psi | 86% | 1877 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 41,234 psi | 87% | 1932 fps | 99.2% |
| Vihtavuori N540 | <<locked>> | 82% | 42,047 psi | 89% | 1886 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 40,364 psi | 86% | 1936 fps | 99% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 41,046 psi | 87% | 2008 fps | 99.7% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 41,133 psi | 87% | 1919 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 42,134 psi | 89% | 1978 fps | 97.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 33,504 psi | 71% | 1972 fps | 99.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 39,885 psi | 85% | 1844 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 39,798 psi | 84% | 1837 fps | 95.9% |
| Accurate 3100 | <<locked>> | 94% | 31,575 psi | 67% | 1811 fps | 95.5% |
| Accurate 4064 | <<locked>> | 80% | 37,768 psi | 80% | 1844 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 27,499 psi | 58% | 1732 fps | 95.9% |
| ADI AR 2208 | <<locked>> | 80% | 37,521 psi | 80% | 1831 fps | 99.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 36,912 psi | 78% | 1847 fps | 99.8% |
| Alliant Reloder-15 | <<locked>> | 80% | 39,697 psi | 84% | 1893 fps | 99.5% |
| Alliant Reloder-16 | 47.4 gr | 80% | 28,645 psi | 61% | 1745 fps | 96.2% |
| Alliant Reloder-17 | 51.1 gr | 80% | 31,720 psi | 67% | 1837 fps | 98.9% |
| Alliant Reloder-23 | <<locked>> | 86% | 24,526 psi | 52% | 1683 fps | 95.8% |
| Alliant Reloder-25 | <<locked>> | 98% | 31,227 psi | 66% | 1841 fps | 95.3% |
| Alliant Reloder-26 | 58.9 gr | 90% | 29,515 psi | 63% | 1850 fps | 95.8% |
| Bofors RP3 | <<locked>> | 80% | 36,274 psi | 77% | 1850 fps | 99.8% |
| Bofors RP7 | <<locked>> | 84% | 37,550 psi | 80% | 1834 fps | 95.5% |
| Hodgdon H380 | <<locked>> | 80% | 37,362 psi | 79% | 1857 fps | 98.3% |
| Hodgdon H414 | <<locked>> | 84% | 34,505 psi | 73% | 1854 fps | 95.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 26,121 psi | 55% | 1673 fps | 97% |
| Hodgdon Superformance | <<locked>> | 86% | 36,100 psi | 77% | 1903 fps | 95.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,353 psi | 56% | 1070 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 39,407 psi | 84% | 1854 fps | 99.5% |
| IMR 4350 | <<locked>> | 88% | 37,652 psi | 80% | 1857 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 80% | 34,621 psi | 73% | 1781 fps | 95% |
| IMR 4831 | <<locked>> | 80% | 27,093 psi | 57% | 1709 fps | 95.7% |
| Lovex S062 | <<locked>> | 80% | 39,146 psi | 83% | 1854 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 31,894 psi | 68% | 1745 fps | 95.8% |
| Lovex S070 | <<locked>> | 84% | 34,272 psi | 73% | 1804 fps | 95.5% |
| Lovex S071 | <<locked>> | 98% | 30,153 psi | 64% | 1785 fps | 95% |
| Norma 203B | <<locked>> | 80% | 39,059 psi | 83% | 1883 fps | 99.7% |
| Norma MRP | <<locked>> | 96% | 36,753 psi | 78% | 1959 fps | 95.8% |
| Norma URP | <<locked>> | 80% | 28,442 psi | 60% | 1739 fps | 96% |
| Ramshot Big Game | <<locked>> | 80% | 38,566 psi | 82% | 1900 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 84% | 31,604 psi | 67% | 1808 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,643 psi | 57% | 1096 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 37,840 psi | 80% | 1847 fps | 96.9% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 33,852 psi | 72% | 1880 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 27,485 psi | 58% | 1745 fps | 95.3% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 29,863 psi | 63% | 1791 fps | 95.3% |
| Rottweil R 903 | <<locked>> | 80% | 34,243 psi | 73% | 1811 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 96% | 39,247 psi | 83% | 1939 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 84% | 37,550 psi | 80% | 1834 fps | 95.5% |
| Shooters World Long Rifle | <<locked>> | 80% | 31,894 psi | 68% | 1745 fps | 95.8% |
| Shooters World Precision | <<locked>> | 80% | 39,146 psi | 83% | 1854 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 34,272 psi | 73% | 1804 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 35,302 psi | 75% | 1850 fps | 99.1% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 37,086 psi | 79% | 1762 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 35,259 psi | 75% | 1778 fps | 95.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 38,914 psi | 83% | 1936 fps | 95% |
| Somchem S355 | <<locked>> | 80% | 35,085 psi | 74% | 1814 fps | 99.4% |
| Somchem S365 | <<locked>> | 80% | 25,251 psi | 54% | 1703 fps | 98.1% |
| Somchem S385 | <<locked>> | 94% | 36,970 psi | 78% | 1886 fps | 95.4% |
| Vihtavuori N150 | <<locked>> | 80% | 33,446 psi | 71% | 1768 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 80% | 29,675 psi | 63% | 1739 fps | 96.4% |
| Vihtavuori N540 | <<locked>> | 80% | 39,494 psi | 84% | 1850 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 29,080 psi | 62% | 1742 fps | 96% |
| Vihtavuori N555 | <<locked>> | 84% | 24,323 psi | 52% | 1696 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 29,486 psi | 63% | 1726 fps | 98.3% |
| Winchester 760 | <<locked>> | 84% | 34,505 psi | 73% | 1854 fps | 95.4% |
| Winchester StaBALL HD | <<locked>> | 90% | 24,337 psi | 52% | 1742 fps | 96.2% |
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 59 powders for .375 Fl. Mag. N.E. loaded with the .375 | 400gr | MAKER REX SUB. Alliant Reloder-26 delivers the highest muzzle velocity at 2,073 fps; across all powders the maximum-charge window runs from 1,201 fps to 2,073 fps. Accurate 3100 gives the best case fill at 100 %, and 59 of the 59 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (325 MPa), the top charges use 69–90 %, leaving at least 10 % headroom. The 400.0 gr projectile in 0.375" calls for a 1:14.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-23, Alliant Reloder-25 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-17, Alliant Reloder-26, Alliant Reloder-16 rank at the top here: for .375 Fl. Mag. N.E. with the .375 | 400gr | MAKER REX SUB they combine a high case fill with complete burn and sit in the upper velocity band. Hodgdon TrailBoss, ReloadSwiss RS 14 stay subsonic at start load. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.