Load Specifications
Load data in caliber .45-70 Govt. with .458 | 405gr | CamPro FCP RNFP bullet and 6 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are 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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant AR-Comp | <<locked>> | 92% | 27,238 psi | 85% | 1759 fps | 96.6% |
| Alliant Reloder-10x | <<locked>> | 86% | 27,934 psi | 88% | 1749 fps | 96.1% |
| Hodgdon TrailBoss | <<locked>> | 96% | 28,471 psi | 89% | 1145 fps | 100% |
| IMR 4198 | <<locked>> | 82% | 27,920 psi | 88% | 1686 fps | 96.6% |
| Norma 200 | <<locked>> | 82% | 27,920 psi | 88% | 1739 fps | 96.9% |
| ReloadSwiss RS 14 | <<locked>> | 98% | 28,732 psi | 90% | 1184 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant AR-Comp | <<locked>> | 90% | 25,701 psi | 81% | 1722 fps | 95.7% |
| Alliant Reloder-10x | <<locked>> | 84% | 26,368 psi | 83% | 1716 fps | 95.4% |
| Hodgdon TrailBoss | 13.8 gr | 80% | 22,046 psi | 69% | 1043 fps | 100% |
| IMR 4198 | <<locked>> | 80% | 26,426 psi | 83% | 1654 fps | 95.9% |
| Norma 200 | <<locked>> | 80% | 26,237 psi | 82% | 1703 fps | 96.3% |
| ReloadSwiss RS 14 | 14.1 gr | 80% | 21,785 psi | 68% | 1070 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
This overview compares 6 powders for .45-70 Govt. loaded with the .458 | 405gr | CamPro FCP RNFP. Alliant AR-Comp delivers the highest muzzle velocity at 1,759 fps; across all powders the maximum-charge window runs from 1,145 fps to 1,759 fps. ReloadSwiss RS 14 gives the best case fill at 98 %, and 6 of the 6 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (220 MPa), the top charges use 85–90 %, leaving at least 10 % headroom. ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .45-70 Govt. with the .458 | 405gr | CamPro FCP RNFP 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.