Load Specifications
Load data in caliber .45-70 Govt. with .458 | 350gr | H&N TC HS bullet and 10 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 |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 84% | 27,499 psi | 86% | 1903 fps | 98.4% |
| ADI AR 2207 | <<locked>> | 84% | 27,325 psi | 86% | 1896 fps | 98.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 28,485 psi | 89% | 1280 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 28,398 psi | 89% | 1276 fps | 100% |
| Norma 200 | <<locked>> | 88% | 28,094 psi | 88% | 1926 fps | 95.9% |
| Norma 200 | <<locked>> | 88% | 28,094 psi | 88% | 1926 fps | 95.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 27,615 psi | 87% | 1306 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 27,760 psi | 87% | 1306 fps | 100% |
| Vihtavuori N120 | <<locked>> | 84% | 27,963 psi | 88% | 1883 fps | 99.3% |
| Vihtavuori N120 | <<locked>> | 84% | 27,789 psi | 87% | 1877 fps | 99.2% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 80% | 24,221 psi | 76% | 1827 fps | 97.2% |
| ADI AR 2207 | <<locked>> | 80% | 24,047 psi | 75% | 1821 fps | 97.1% |
| Hodgdon TrailBoss | 14.6 gr | 80% | 20,479 psi | 64% | 1142 fps | 100% |
| Hodgdon TrailBoss | 14.6 gr | 80% | 20,363 psi | 64% | 1138 fps | 100% |
| Norma 200 | <<locked>> | 86% | 26,368 psi | 83% | 1890 fps | 95.1% |
| Norma 200 | <<locked>> | 86% | 26,208 psi | 82% | 1883 fps | 95% |
| ReloadSwiss RS 14 | 14.9 gr | 80% | 19,943 psi | 63% | 1168 fps | 100% |
| ReloadSwiss RS 14 | 14.9 gr | 80% | 19,827 psi | 62% | 1165 fps | 100% |
| Vihtavuori N120 | <<locked>> | 80% | 24,656 psi | 77% | 1811 fps | 98.4% |
| Vihtavuori N120 | <<locked>> | 80% | 24,526 psi | 77% | 1808 fps | 98.3% |
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 10 powders for .45-70 Govt. loaded with the .458 | 350gr | H&N TC HS. Norma 200 delivers the highest muzzle velocity at 1,926 fps; across all powders the maximum-charge window runs from 1,276 fps to 1,926 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 10 of the 10 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (220 MPa), the top charges use 86–89 %, leaving at least 11 % headroom. Hodgdon TrailBoss, 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. ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .45-70 Govt. with the .458 | 350gr | H&N TC HS 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.