Load Specifications
Load data in caliber 9 x 57 Mauser with .358 | 130gr | Rim Rock RNFP Cowboy bullet and 11 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2207, Vihtavuori N120 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: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 88% | 34,679 psi | 85% | 2917 fps | 98.7% |
| Alliant Reloder-7 | <<locked>> | 88% | 36,709 psi | 90% | 2907 fps | 96.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 29,051 psi | 72% | 1942 fps | 100% |
| IMR 4198 | <<locked>> | 92% | 35,984 psi | 89% | 2894 fps | 96.2% |
| IMR 4227 | <<locked>> | 82% | 36,738 psi | 90% | 2861 fps | 98% |
| Lovex S053 | <<locked>> | 82% | 35,331 psi | 87% | 2831 fps | 99.7% |
| Norma 200 | <<locked>> | 92% | 36,361 psi | 90% | 2959 fps | 96.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 28,224 psi | 70% | 1982 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 82% | 35,447 psi | 87% | 2874 fps | 97.5% |
| SNPE Vectan BA6 1/2 | <<locked>> | 84% | 35,259 psi | 87% | 2703 fps | 100% |
| Vihtavuori N120 | <<locked>> | 88% | 35,012 psi | 86% | 2887 fps | 99.4% |
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 |
|---|---|---|---|---|---|---|
| ADI AR 2207 | 41.8 gr | 80% | 26,484 psi | 65% | 2684 fps | 95.9% |
| Alliant Reloder-7 | <<locked>> | 86% | 34,548 psi | 85% | 2851 fps | 95.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 20,900 psi | 51% | 1736 fps | 100% |
| IMR 4198 | <<locked>> | 90% | 33,939 psi | 84% | 2838 fps | 95.5% |
| IMR 4227 | <<locked>> | 80% | 34,505 psi | 85% | 2805 fps | 97.4% |
| Lovex S053 | <<locked>> | 80% | 33,214 psi | 82% | 2779 fps | 99.4% |
| Norma 200 | <<locked>> | 90% | 33,968 psi | 84% | 2897 fps | 95.7% |
| ReloadSwiss RS 14 | 15.4 gr | 80% | 20,378 psi | 50% | 1772 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 80% | 33,141 psi | 82% | 2815 fps | 96.8% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 31,270 psi | 77% | 2618 fps | 100% |
| Vihtavuori N120 | 41.8 gr | 80% | 26,861 psi | 66% | 2664 fps | 97.3% |
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 20 powders for 9 x 57 Mauser loaded with the .358 | 130gr | Rim Rock RNFP Cowboy. Norma 200 delivers the highest muzzle velocity at 2,959 fps; across all powders the maximum-charge window runs from 1,942 fps to 2,959 fps. Accurate 2015 gives the best case fill at 100 %, and 20 of the 20 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (280 MPa), the top charges use 70–90 %, leaving at least 10 % headroom. Accurate 2015, Alliant AR-Comp, Hodgdon TrailBoss 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. ADI AR 2207, Vihtavuori N120, ReloadSwiss RS 14 rank at the top here: for 9 x 57 Mauser with the .358 | 130gr | Rim Rock RNFP Cowboy they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 2015, Accurate LT-30, Alliant Reloder-10x 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.