Load Specifications
Load data in caliber 8 x 58 R with .318 | 196gr | Impala RNFP KO bullet and 5 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate 2495, 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: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 88% | 27,963 psi | 88% | 1900 fps | 97% |
| Alliant AR-Comp | <<locked>> | 82% | 28,021 psi | 88% | 1886 fps | 98.7% |
| Hodgdon TrailBoss | <<locked>> | 90% | 28,558 psi | 90% | 1217 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 90% | 28,616 psi | 90% | 1250 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 27,572 psi | 86% | 1860 fps | 96.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | 25.1 gr | 82% | 23,685 psi | 74% | 1795 fps | 95% |
| Alliant AR-Comp | <<locked>> | 80% | 26,542 psi | 83% | 1850 fps | 98.2% |
| Hodgdon TrailBoss | 8.4 gr | 80% | 24,337 psi | 76% | 1145 fps | 100% |
| ReloadSwiss RS 14 | 8.6 gr | 80% | 24,497 psi | 77% | 1175 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 26,092 psi | 82% | 1824 fps | 95.6% |
Recommended = one of the top powders for this cartridge and bullet combination.
This overview compares 5 powders for 8 x 58 R loaded with the .318 | 196gr | Impala RNFP KO. Accurate 2495 delivers the highest muzzle velocity at 1,900 fps; across all powders the maximum-charge window runs from 1,217 fps to 1,900 fps. Hodgdon TrailBoss gives the best case fill at 90 %, and 5 of the 5 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (220 MPa), the top charges use 86–90 %, leaving at least 10 % headroom. The 196.0 gr projectile in 0.318" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. Accurate 2495, ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for 8 x 58 R with the .318 | 196gr | Impala RNFP KO 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.