Load Specifications
Load data in caliber .505 Mag. Gibbs with .505 | 535gr | Swift A-Frame bullet and 14 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Somchem S365, Alliant Reloder-23 and Hodgdon Hybrid 100V.
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 |
|---|---|---|---|---|---|---|
| Accurate 4350 | <<locked>> | 88% | 35,331 psi | 90% | 2260 fps | 96.3% |
| Alliant Reloder-17 | <<locked>> | 84% | 35,375 psi | 90% | 2290 fps | 98% |
| Alliant Reloder-23 | <<locked>> | 98% | 34,635 psi | 88% | 2280 fps | 97.6% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 35,012 psi | 89% | 2228 fps | 97.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,331 psi | 90% | 1493 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 34,243 psi | 87% | 2221 fps | 95.9% |
| ReloadSwiss RS 14 | <<locked>> | 98% | 34,853 psi | 89% | 1512 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 35,230 psi | 90% | 2297 fps | 99.6% |
| Somchem S365 | <<locked>> | 90% | 34,098 psi | 87% | 2270 fps | 98.9% |
| Vihtavuori N150 | <<locked>> | 82% | 34,751 psi | 89% | 2169 fps | 98.9% |
| Vihtavuori N160 | <<locked>> | 86% | 35,172 psi | 90% | 2218 fps | 95.9% |
| Vihtavuori N555 | <<locked>> | 96% | 34,954 psi | 89% | 2300 fps | 96.9% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 35,172 psi | 90% | 2201 fps | 98% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 32,793 psi | 84% | 2316 fps | 97.7% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 4350 | <<locked>> | 86% | 33,011 psi | 84% | 2211 fps | 95.4% |
| Alliant Reloder-17 | <<locked>> | 80% | 31,024 psi | 79% | 2185 fps | 96.4% |
| Alliant Reloder-23 | 122.7 gr | 92% | 28,950 psi | 74% | 2136 fps | 95.1% |
| Hodgdon Hybrid 100V | 110.7 gr | 84% | 29,008 psi | 74% | 2087 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,281 psi | 67% | 1332 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 32,126 psi | 82% | 2175 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,600 psi | 68% | 1362 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 33,025 psi | 84% | 2247 fps | 99.2% |
| Somchem S365 | 111.1 gr | 82% | 26,484 psi | 68% | 2073 fps | 95.9% |
| Vihtavuori N150 | <<locked>> | 80% | 32,605 psi | 83% | 2123 fps | 98.4% |
| Vihtavuori N160 | <<locked>> | 84% | 33,011 psi | 84% | 2169 fps | 95% |
| Vihtavuori N555 | <<locked>> | 92% | 30,734 psi | 78% | 2201 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 28,979 psi | 74% | 2057 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 96% | 28,935 psi | 74% | 2201 fps | 95.3% |
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 35 powders for .505 Mag. Gibbs loaded with the .505 | 535gr | Swift A-Frame. Alliant Reloder-26 delivers the highest muzzle velocity at 2,346 fps; across all powders the maximum-charge window runs from 1,493 fps to 2,346 fps. Alliant Reloder-25 gives the best case fill at 100 %, and 35 of the 35 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 80–90 %, leaving at least 10 % headroom. Alliant Reloder-25, Hodgdon TrailBoss, Lovex S071 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, Alliant Reloder-23, Hodgdon Hybrid 100V rank at the top here: for .505 Mag. Gibbs with the .505 | 535gr | Swift A-Frame they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 3100, Alliant Reloder-25, Bofors RP7 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.