Load Specifications
Load data in caliber 9 mm Steyr with .356 | 123gr | LOS FP bullet and 9 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>> | 68% | 16,143 psi | 82% | 988 fps | 95.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 72% | 16,810 psi | 86% | 968 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 14,736 psi | 75% | 873 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 13,373 psi | 68% | 866 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 64% | 17,042 psi | 87% | 1040 fps | 97.8% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 68% | 17,172 psi | 88% | 1007 fps | 87.4% |
| Vihtavuori 3N37*² | <<locked>> | 64% | 16,969 psi | 87% | 1030 fps | 88.7% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 16,433 psi | 84% | 896 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 68% | 16,824 psi | 86% | 1027 fps | 89% |
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% | 13,213 psi | 67% | 902 fps | 92.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 12,546 psi | 64% | 863 fps | 100% |
| Hodgdon TrailBoss² | 2.3 gr | 60% | 7,658 psi | 39% | 650 fps | 99.2% |
| ReloadSwiss RS 14² | 2.4 gr | 60% | 7,556 psi | 39% | 653 fps | 96.3% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 15,258 psi | 78% | 994 fps | 96.6% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 15,621 psi | 80% | 968 fps | 85.7% |
| Vihtavuori 3N37*² | <<locked>> | 60% | 15,418 psi | 79% | 991 fps | 87% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 11,414 psi | 58% | 778 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 15,200 psi | 78% | 984 fps | 87.1% |
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 FP. ReloadSwiss RS 20 delivers the highest muzzle velocity at 1,040 fps; across all powders the maximum-charge window runs from 866 fps to 1,040 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 68–88 %, leaving at least 12 % 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 .356 | 123gr | LOS FP 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.