Load Specifications
Load data in caliber .458 SOCOM with .458 | 300gr | Nosler Ballistic Tip Muzzle Loader bullet and 4 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are SNPE Vectan BA6 1/2, ReloadSwiss RS 14 and Hodgdon TrailBoss.
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: 16"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 25,498 psi | 73% | 1234 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 24,439 psi | 70% | 1260 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 92% | 30,472 psi | 87% | 1785 fps | 100% |
| Vihtavuori N110 | <<locked>> | 84% | 30,356 psi | 87% | 1824 fps | 99.6% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 16"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Hodgdon TrailBoss | 12.5 gr | 80% | 18,217 psi | 52% | 1099 fps | 100% |
| ReloadSwiss RS 14 | 12.7 gr | 80% | 17,376 psi | 50% | 1119 fps | 100% |
| SNPE Vectan BA6 1/2 | 30.4 gr | 80% | 21,712 psi | 62% | 1604 fps | 98.7% |
| Vihtavuori N110 | <<locked>> | 80% | 26,716 psi | 76% | 1752 fps | 98.9% |
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 7 powders for .458 SOCOM loaded with the .458 | 300gr | Nosler Ballistic Tip Muzzle Loader. ADI AR 2207 delivers the highest muzzle velocity at 1,900 fps; across all powders the maximum-charge window runs from 1,234 fps to 1,900 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 7 of the 7 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (241 MPa), the top charges use 70–89 %, leaving at least 11 % headroom. Hodgdon TrailBoss, ReloadSwiss RS 14 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. SNPE Vectan BA6 1/2, ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .458 SOCOM with the .458 | 300gr | Nosler Ballistic Tip Muzzle Loader they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2207, Vihtavuori N120 burn incompletely and react more sensitively to barrel length and temperature. 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.