Load Specifications
Load data in caliber .45-70 Govt. with .454 | 255gr | Hornady Lead Bullets bullet and 4 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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 27,673 psi | 87% | 1522 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 26,789 psi | 84% | 1555 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 82% | 27,543 psi | 86% | 2064 fps | 100% |
| Vihtavuori N120 | <<locked>> | 88% | 27,905 psi | 87% | 2195 fps | 96.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Hodgdon TrailBoss | 15.8 gr | 80% | 20,059 psi | 63% | 1362 fps | 100% |
| ReloadSwiss RS 14 | 16.1 gr | 80% | 19,537 psi | 61% | 1391 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 26,150 psi | 82% | 2034 fps | 100% |
| Vihtavuori N120 | <<locked>> | 86% | 26,324 psi | 83% | 2152 fps | 95.6% |
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 .45-70 Govt. loaded with the .454 | 255gr | Hornady Lead Bullets. Norma 200 delivers the highest muzzle velocity at 2,234 fps; across all powders the maximum-charge window runs from 1,522 fps to 2,234 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 (220 MPa), the top charges use 84–90 %, 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. ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .45-70 Govt. with the .454 | 255gr | Hornady Lead Bullets they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2207, Norma 200, ReloadSwiss RS 36 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.