Load Specifications
Load data in caliber .505 Mag. Gibbs with .505 | 525gr | Hornady DGX bullet and 12 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Somchem S365, Hodgdon Hybrid 100V and ReloadSwiss RS 14.
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 Reloder-17 | <<locked>> | 84% | 34,389 psi | 88% | 2283 fps | 97.4% |
| Alliant Reloder-23 | <<locked>> | 98% | 33,649 psi | 86% | 2270 fps | 96.9% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 34,011 psi | 87% | 2221 fps | 97.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,244 psi | 90% | 1503 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 98% | 34,650 psi | 88% | 1522 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 34,345 psi | 88% | 2293 fps | 99.3% |
| Rottweil R 903 | <<locked>> | 82% | 34,708 psi | 89% | 2218 fps | 97.8% |
| Somchem S365 | <<locked>> | 92% | 35,288 psi | 90% | 2310 fps | 98.9% |
| Vihtavuori N150 | <<locked>> | 82% | 33,895 psi | 87% | 2169 fps | 98.5% |
| Vihtavuori N555 | <<locked>> | 96% | 33,750 psi | 86% | 2290 fps | 96.1% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 34,330 psi | 88% | 2198 fps | 97.4% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 31,879 psi | 81% | 2300 fps | 96.7% |
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 Reloder-17 | <<locked>> | 80% | 30,211 psi | 77% | 2182 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 94% | 29,878 psi | 76% | 2175 fps | 95.1% |
| Hodgdon Hybrid 100V | 112.3 gr | 86% | 30,066 psi | 77% | 2129 fps | 95.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,223 psi | 67% | 1339 fps | 100% |
| ReloadSwiss RS 14 | 37.1 gr | 80% | 26,527 psi | 68% | 1371 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 32,198 psi | 82% | 2241 fps | 98.8% |
| Rottweil R 903 | <<locked>> | 80% | 32,474 psi | 83% | 2169 fps | 97.1% |
| Somchem S365 | 110.1 gr | 82% | 25,788 psi | 66% | 2067 fps | 95.1% |
| Vihtavuori N150 | <<locked>> | 80% | 31,734 psi | 81% | 2123 fps | 97.9% |
| Vihtavuori N555 | <<locked>> | 94% | 31,705 psi | 81% | 2244 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 30,182 psi | 77% | 2100 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 98% | 29,950 psi | 76% | 2241 fps | 95.4% |
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 33 powders for .505 Mag. Gibbs loaded with the .505 | 525gr | Hornady DGX. Alliant Reloder-26 delivers the highest muzzle velocity at 2,333 fps; across all powders the maximum-charge window runs from 1,503 fps to 2,333 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 33 of the 33 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 77–90 %, leaving at least 10 % headroom. Hodgdon TrailBoss, Lovex S071, Winchester StaBALL HD 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. Somchem S365, Hodgdon Hybrid 100V, ReloadSwiss RS 14 rank at the top here: for .505 Mag. Gibbs with the .505 | 525gr | Hornady DGX they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 3100, Alliant Reloder-26, Hodgdon H414 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.