Load Specifications
Load data in caliber .458 SOCOM with .459 | 430gr | Rim Rock LBT?WFN Gas Check bullet and 6 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N120, 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 |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 94% | 31,372 psi | 90% | 1549 fps | 97.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 26,948 psi | 77% | 974 fps | 100% |
| Lovex S053 | <<locked>> | 86% | 31,343 psi | 90% | 1480 fps | 98.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 26,194 psi | 75% | 997 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 88% | 31,430 psi | 90% | 1417 fps | 100% |
| Vihtavuori N120 | <<locked>> | 92% | 30,124 psi | 86% | 1506 fps | 97.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 16"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 88% | 25,976 psi | 74% | 1457 fps | 95% |
| Hodgdon TrailBoss | 10.4 gr | 80% | 19,334 psi | 55% | 866 fps | 100% |
| Lovex S053 | <<locked>> | 80% | 26,049 psi | 74% | 1394 fps | 97.3% |
| ReloadSwiss RS 14 | 10.6 gr | 80% | 18,666 psi | 53% | 886 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 25,135 psi | 72% | 1325 fps | 100% |
| Vihtavuori N120 | 30.4 gr | 84% | 23,598 psi | 67% | 1388 fps | 95.1% |
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 6 powders for .458 SOCOM loaded with the .459 | 430gr | Rim Rock LBT?WFN Gas Check. ADI AR 2207 delivers the highest muzzle velocity at 1,549 fps; across all powders the maximum-charge window runs from 974 fps to 1,549 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 6 of the 6 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (241 MPa), the top charges use 75–90 %, leaving at least 10 % 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. Vihtavuori N120, ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .458 SOCOM with the .459 | 430gr | Rim Rock LBT?WFN Gas Check 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.