Load Specifications
Load data in caliber .375 Fl. Mag. N.E. with .375 | 300gr | Speer AGS SP bullet and 40 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-16 and Somchem S365.
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 4064 | <<locked>> | 82% | 40,727 psi | 86% | 2267 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 41,930 psi | 89% | 2362 fps | 98.2% |
| ADI AR 2208 | <<locked>> | 84% | 42,279 psi | 90% | 2283 fps | 98.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 42,525 psi | 90% | 2405 fps | 98.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 41,858 psi | 89% | 2303 fps | 99.5% |
| Alliant Reloder-15 | <<locked>> | 82% | 42,177 psi | 89% | 2313 fps | 98.7% |
| Alliant Reloder-16 | <<locked>> | 92% | 41,495 psi | 88% | 2365 fps | 98.3% |
| Alliant Reloder-17 | <<locked>> | 88% | 41,423 psi | 88% | 2392 fps | 99.4% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 37,811 psi | 80% | 2326 fps | 98.7% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 41,800 psi | 89% | 2461 fps | 97.8% |
| Bofors RP3 | <<locked>> | 84% | 41,727 psi | 89% | 2313 fps | 99.6% |
| Hodgdon H380 | <<locked>> | 84% | 42,656 psi | 90% | 2316 fps | 97.8% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 40,611 psi | 86% | 2313 fps | 99.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,433 psi | 75% | 1483 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 41,742 psi | 89% | 2267 fps | 98.7% |
| IMR 4831 | <<locked>> | 92% | 40,234 psi | 85% | 2316 fps | 97.8% |
| Lovex S062 | <<locked>> | 82% | 41,742 psi | 89% | 2274 fps | 99.7% |
| Lovex S065 | <<locked>> | 88% | 41,147 psi | 87% | 2270 fps | 96.5% |
| Norma 203B | <<locked>> | 82% | 41,510 psi | 88% | 2303 fps | 99% |
| Norma URP | <<locked>> | 92% | 41,872 psi | 89% | 2356 fps | 98% |
| Ramshot Big Game | <<locked>> | 82% | 41,104 psi | 87% | 2320 fps | 98.8% |
| Ramshot Hunter | <<locked>> | 92% | 40,872 psi | 87% | 2343 fps | 96% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,911 psi | 76% | 1519 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 41,336 psi | 88% | 2395 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 41,437 psi | 88% | 2375 fps | 97.8% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 41,640 psi | 88% | 2388 fps | 97.2% |
| Rottweil R 903 | <<locked>> | 86% | 41,785 psi | 89% | 2306 fps | 99.4% |
| Shooters World Long Rifle | <<locked>> | 88% | 41,147 psi | 87% | 2270 fps | 96.5% |
| Shooters World Precision | <<locked>> | 82% | 41,742 psi | 89% | 2274 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 40,306 psi | 86% | 2310 fps | 98.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 41,814 psi | 89% | 2205 fps | 100% |
| Somchem S355 | <<locked>> | 86% | 42,598 psi | 90% | 2310 fps | 99.4% |
| Somchem S365 | <<locked>> | 96% | 42,569 psi | 90% | 2408 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 40,669 psi | 86% | 2254 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 90% | 41,060 psi | 87% | 2306 fps | 97.8% |
| Vihtavuori N540 | <<locked>> | 82% | 42,003 psi | 89% | 2267 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 40,335 psi | 86% | 2310 fps | 97.4% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 40,988 psi | 87% | 2392 fps | 98.6% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 41,031 psi | 87% | 2290 fps | 99.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 33,707 psi | 72% | 2323 fps | 98.4% |
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 4064 | <<locked>> | 80% | 38,203 psi | 81% | 2224 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 31,879 psi | 68% | 2162 fps | 95.1% |
| ADI AR 2208 | <<locked>> | 80% | 37,333 psi | 79% | 2192 fps | 97.5% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 39,798 psi | 84% | 2352 fps | 98% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 36,883 psi | 78% | 2211 fps | 98.8% |
| Alliant Reloder-15 | <<locked>> | 80% | 39,624 psi | 84% | 2267 fps | 98.2% |
| Alliant Reloder-16 | 62.2 gr | 84% | 32,547 psi | 69% | 2175 fps | 95.2% |
| Alliant Reloder-17 | 63.8 gr | 80% | 31,807 psi | 67% | 2185 fps | 96.9% |
| Alliant Reloder-23 | <<locked>> | 92% | 29,675 psi | 63% | 2136 fps | 95.7% |
| Alliant Reloder-26 | <<locked>> | 96% | 36,521 psi | 77% | 2349 fps | 96% |
| Bofors RP3 | <<locked>> | 80% | 36,506 psi | 77% | 2218 fps | 98.8% |
| Hodgdon H380 | <<locked>> | 80% | 37,275 psi | 79% | 2218 fps | 96.4% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 27,992 psi | 59% | 2041 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,440 psi | 56% | 1322 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 39,189 psi | 83% | 2221 fps | 98.2% |
| IMR 4831 | <<locked>> | 86% | 33,156 psi | 70% | 2175 fps | 95.7% |
| Lovex S062 | <<locked>> | 80% | 39,189 psi | 83% | 2228 fps | 99.4% |
| Lovex S065 | <<locked>> | 84% | 36,376 psi | 77% | 2178 fps | 95% |
| Norma 203B | <<locked>> | 80% | 39,015 psi | 83% | 2257 fps | 98.5% |
| Norma URP | <<locked>> | 84% | 32,445 psi | 69% | 2165 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 80% | 38,450 psi | 82% | 2270 fps | 98.3% |
| Ramshot Hunter | <<locked>> | 90% | 38,464 psi | 82% | 2297 fps | 95.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,774 psi | 57% | 1355 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 33,837 psi | 72% | 2244 fps | 99.5% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 33,866 psi | 72% | 2224 fps | 95.4% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 36,535 psi | 78% | 2283 fps | 95.4% |
| Rottweil R 903 | <<locked>> | 80% | 34,432 psi | 73% | 2169 fps | 98.1% |
| Shooters World Long Rifle | <<locked>> | 84% | 36,376 psi | 77% | 2178 fps | 95% |
| Shooters World Precision | <<locked>> | 80% | 39,189 psi | 83% | 2228 fps | 99.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 35,230 psi | 75% | 2211 fps | 97.5% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 36,927 psi | 78% | 2126 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 35,244 psi | 75% | 2175 fps | 98.1% |
| Somchem S365 | 60.5 gr | 80% | 25,570 psi | 54% | 2028 fps | 95.6% |
| Vihtavuori N150 | <<locked>> | 80% | 33,533 psi | 71% | 2119 fps | 98.7% |
| Vihtavuori N160 | <<locked>> | 84% | 33,910 psi | 72% | 2169 fps | 95.6% |
| Vihtavuori N540 | <<locked>> | 80% | 39,349 psi | 83% | 2224 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 33,301 psi | 71% | 2169 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 92% | 31,807 psi | 67% | 2205 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 29,762 psi | 63% | 2057 fps | 96.2% |
| Winchester StaBALL HD | <<locked>> | 96% | 29,747 psi | 63% | 2208 fps | 96.3% |
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 40 powders for .375 Fl. Mag. N.E. loaded with the .375 | 300gr | Speer AGS SP. Alliant Reloder-26 delivers the highest muzzle velocity at 2,461 fps; across all powders the maximum-charge window runs from 1,483 fps to 2,461 fps. Alliant Reloder-23 gives the best case fill at 100 %, and 40 of the 40 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (325 MPa), the top charges use 72–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.375" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. Alliant Reloder-23, Alliant Reloder-26, Hodgdon TrailBoss 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-16, Somchem S365 rank at the top here: for .375 Fl. Mag. N.E. with the .375 | 300gr | Speer AGS SP 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.