Load Specifications
Load data in caliber .38 Special with .356 | 147gr | Rim Rock FP bullet and 8 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: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 68% | 18,826 psi | 87% | 945 fps | 98.4% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 68% | 18,434 psi | 85% | 889 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 16,665 psi | 77% | 820 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 15,331 psi | 70% | 820 fps | 100% |
| Rottweil P 806*² | <<locked>> | 68% | 18,579 psi | 85% | 1007 fps | 90% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 18,420 psi | 85% | 935 fps | 91.5% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 19,305 psi | 89% | 850 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 18,724 psi | 86% | 958 fps | 93.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 60% | 15,273 psi | 70% | 866 fps | 96.2% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 14,634 psi | 67% | 817 fps | 100% |
| Hodgdon TrailBoss² | 2.9 gr | 60% | 7,556 psi | 35% | 597 fps | 99.8% |
| ReloadSwiss RS 14² | 3 gr | 60% | 7,252 psi | 33% | 597 fps | 97.2% |
| Rottweil P 806*² | <<locked>> | 64% | 16,027 psi | 74% | 948 fps | 86.9% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 16,476 psi | 76% | 892 fps | 89.5% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 12,966 psi | 60% | 735 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 16,578 psi | 76% | 912 fps | 91.3% |
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 8 powders for .38 Special loaded with the .356 | 147gr | Rim Rock FP. Rottweil P 806 delivers the highest muzzle velocity at 1,007 fps; across all powders the maximum-charge window runs from 820 fps to 1,007 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 8 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 70–89 %, leaving at least 11 % 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 .38 Special with the .356 | 147gr | Rim Rock FP 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 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.