Load Specifications
Load data in caliber 9 mm Steyr with .357 | 158gr | X-TREME RP HP bullet and 11 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 ≥ 60% and propellant combustion ≥ 80%. 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: 5"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 72% | 17,172 psi | 88% | 837 fps | 97.3% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 72% | 16,230 psi | 83% | 784 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 14,156 psi | 72% | 702 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 13,489 psi | 69% | 712 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 64% | 16,563 psi | 85% | 846 fps | 98.6% |
| Rottweil P 806*² | <<locked>> | 76% | 16,070 psi | 82% | 919 fps | 88.4% |
| SNPE Vectan A0² | <<locked>> | 64% | 17,405 psi | 89% | 810 fps | 97% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 68% | 16,766 psi | 86% | 823 fps | 88.9% |
| Vihtavuori 3N37*² | <<locked>> | 64% | 16,491 psi | 84% | 843 fps | 90.3% |
| Vihtavuori N32C Tin Star | <<locked>> | 80% | 16,810 psi | 86% | 735 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 72% | 17,651 psi | 90% | 866 fps | 91.8% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 5"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco*² | <<locked>> | 60% | 12,691 psi | 65% | 732 fps | 93.2% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 12,140 psi | 62% | 702 fps | 100% |
| Hodgdon TrailBoss² | 1.7 gr | 60% | 7,397 psi | 38% | 522 fps | 99.6% |
| ReloadSwiss RS 14² | 1.8 gr | 60% | 7,397 psi | 38% | 528 fps | 97.2% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 15,084 psi | 77% | 814 fps | 97.8% |
| Rottweil P 806*² | <<locked>> | 72% | 14,547 psi | 74% | 883 fps | 86.4% |
| SNPE Vectan A0² | <<locked>> | 60% | 15,809 psi | 81% | 781 fps | 95.8% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 13,634 psi | 70% | 751 fps | 85.1% |
| Vihtavuori 3N37*² | <<locked>> | 60% | 14,533 psi | 74% | 797 fps | 88% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 11,574 psi | 59% | 640 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 12,995 psi | 66% | 758 fps | 86.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
* not dangerous but load has suboptimal powder burnt with possible characteristics such as extensive muzzle flash or inaccurate loads.
² fill rate low - you might want to consider using a filler to ensure proper ignition.
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 11 powders for 9 mm Steyr loaded with the .357 | 158gr | X-TREME RP HP. Rottweil P 806 delivers the highest muzzle velocity at 919 fps; across all powders the maximum-charge window runs from 702 fps to 919 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 3 of the 11 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (135 MPa), the top charges use 69–90 %, 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 9 mm Steyr with the .357 | 158gr | X-TREME RP HP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Rottweil P 806, SNPE Vectan BA7 1/2, Vihtavuori 3N37 burn incompletely and react more sensitively to barrel length and temperature. Alliant Herco, Baschieri & Pellagri 102 Pistol, Hodgdon TrailBoss stay subsonic at start load. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.