Load Specifications
Load data in caliber 9 mm Steyr with .357 | 125gr | Hornady XTP bullet and 13 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon TrailBoss 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 ≥ 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% | 16,099 psi | 82% | 1004 fps | 95.5% |
| Alliant UNIQUE² | <<locked>> | 64% | 17,666 psi | 90% | 1047 fps | 96.6% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 76% | 17,216 psi | 88% | 988 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 12,691 psi | 65% | 846 fps | 100% |
| Maxam CSB 1² | <<locked>> | 64% | 16,694 psi | 85% | 981 fps | 99.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 11,574 psi | 59% | 843 fps | 99.8% |
| ReloadSwiss RS 20² | <<locked>> | 68% | 17,651 psi | 90% | 1066 fps | 98.5% |
| Rottweil P 806* | <<locked>> | 80% | 17,332 psi | 89% | 1142 fps | 87.8% |
| SNPE Vectan A0² | <<locked>> | 64% | 17,085 psi | 87% | 994 fps | 96% |
| Vihtavuori 3N37*² | <<locked>> | 64% | 16,056 psi | 82% | 1020 fps | 88.3% |
| Vihtavuori N32C Tin Star | <<locked>> | 84% | 17,535 psi | 90% | 935 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 72% | 17,143 psi | 88% | 1047 fps | 89.9% |
| Winchester AutoComp ² | <<locked>> | 64% | 17,637 psi | 90% | 1017 fps | 99.4% |
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% | 11,647 psi | 59% | 876 fps | 90.3% |
| Alliant UNIQUE² | <<locked>> | 60% | 15,722 psi | 80% | 997 fps | 95.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 11,066 psi | 57% | 843 fps | 99.9% |
| Hodgdon TrailBoss² | 2.4 gr | 60% | 6,179 psi | 32% | 627 fps | 97.4% |
| Maxam CSB 1² | <<locked>> | 60% | 15,389 psi | 79% | 951 fps | 99.2% |
| ReloadSwiss RS 14*² | 2.4 gr | 60% | 5,671 psi | 29% | 607 fps | 92.1% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 13,982 psi | 71% | 971 fps | 95.8% |
| Rottweil P 806*² | <<locked>> | 76% | 15,389 psi | 79% | 1093 fps | 85.4% |
| SNPE Vectan A0*² | <<locked>> | 60% | 15,229 psi | 78% | 948 fps | 94.4% |
| Vihtavuori 3N37*² | <<locked>> | 60% | 13,967 psi | 71% | 965 fps | 85.6% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 9,790 psi | 50% | 761 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 13,851 psi | 71% | 958 fps | 85.9% |
| Winchester AutoComp ² | <<locked>> | 60% | 15,287 psi | 78% | 961 fps | 98.4% |
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 13 powders for 9 mm Steyr loaded with the .357 | 125gr | Hornady XTP. Rottweil P 806 delivers the highest muzzle velocity at 1,142 fps; across all powders the maximum-charge window runs from 843 fps to 1,142 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 4 of the 13 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (135 MPa), the top charges use 59–90 %, 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. Hodgdon TrailBoss, ReloadSwiss RS 14 rank at the top here: for 9 mm Steyr with the .357 | 125gr | Hornady XTP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Rottweil P 806, Vihtavuori 3N37, Vihtavuori N350 burn incompletely and react more sensitively to barrel length and temperature. Alliant Herco, Alliant UNIQUE, Baschieri & Pellagri 102 Pistol 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.