Load Specifications
Load data in caliber 9 mm Steyr with .356 | 123gr | LOS HP bullet and 9 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% | 17,709 psi | 90% | 1033 fps | 96.5% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 72% | 17,419 psi | 89% | 984 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 14,881 psi | 76% | 879 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 13,967 psi | 71% | 886 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 64% | 17,622 psi | 90% | 1060 fps | 98.3% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 68% | 17,521 psi | 89% | 1024 fps | 88.2% |
| Vihtavuori 3N37*² | <<locked>> | 64% | 17,463 psi | 89% | 1050 fps | 89.6% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 16,578 psi | 85% | 906 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 68% | 17,260 psi | 88% | 1047 fps | 89.9% |
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% | 13,692 psi | 70% | 925 fps | 93% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 13,111 psi | 67% | 883 fps | 100% |
| Hodgdon TrailBoss² | 2.4 gr | 60% | 7,847 psi | 40% | 663 fps | 99.5% |
| ReloadSwiss RS 14² | 2.4 gr | 60% | 7,440 psi | 38% | 653 fps | 96.4% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 15,867 psi | 81% | 1014 fps | 97.2% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 16,070 psi | 82% | 984 fps | 86.6% |
| Vihtavuori 3N37*² | <<locked>> | 60% | 15,896 psi | 81% | 1007 fps | 87.9% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 11,632 psi | 59% | 787 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 13,750 psi | 70% | 945 fps | 85.5% |
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 9 powders for 9 mm Steyr loaded with the .356 | 123gr | LOS HP. ReloadSwiss RS 20 delivers the highest muzzle velocity at 1,060 fps; across all powders the maximum-charge window runs from 879 fps to 1,060 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 9 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (135 MPa), the top charges use 71–90 %, 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 .356 | 123gr | LOS HP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, SNPE Vectan BA7 1/2, Vihtavuori 3N37, Vihtavuori N350 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.