Load Specifications
Load data in caliber .38 Special with .358 | 158gr | Rim Rock SWC?HP Gas Check 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: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AP 100*² | <<locked>> | 72% | 19,479 psi | 90% | 932 fps | 87.5% |
| Alliant Herco² | <<locked>> | 68% | 19,072 psi | 88% | 906 fps | 99% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 68% | 18,565 psi | 85% | 846 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 17,085 psi | 79% | 787 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 15,737 psi | 72% | 791 fps | 100% |
| Rottweil P 806*² | <<locked>> | 68% | 18,869 psi | 87% | 974 fps | 91.6% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 18,840 psi | 87% | 906 fps | 92.9% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 19,174 psi | 88% | 804 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 19,160 psi | 88% | 925 fps | 94.6% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AP 100*² | <<locked>> | 68% | 17,347 psi | 80% | 886 fps | 85.2% |
| Alliant Herco² | <<locked>> | 60% | 15,331 psi | 70% | 830 fps | 97% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 15,098 psi | 69% | 787 fps | 100% |
| Hodgdon TrailBoss² | 2.8 gr | 60% | 7,818 psi | 36% | 577 fps | 100% |
| ReloadSwiss RS 14² | 2.9 gr | 60% | 7,498 psi | 34% | 577 fps | 98.1% |
| Rottweil P 806*² | <<locked>> | 60% | 14,170 psi | 65% | 866 fps | 85.7% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 16,766 psi | 77% | 860 fps | 90.9% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 13,111 psi | 60% | 702 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 16,839 psi | 77% | 879 fps | 92.6% |
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 .38 Special loaded with the .358 | 158gr | Rim Rock SWC?HP Gas Check. Rottweil P 806 delivers the highest muzzle velocity at 974 fps; across all powders the maximum-charge window runs from 787 fps to 974 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 (150 MPa), the top charges use 72–90 %, 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 .38 Special with the .358 | 158gr | Rim Rock SWC?HP Gas Check they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AP 100, Rottweil P 806, SNPE Vectan BA7 1/2 burn incompletely and react more sensitively to barrel length and temperature. ADI AP 100, Alliant Herco, 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.