Load Specifications
Load data in caliber .38 Special with .357 | 158gr | Zero JHP bullet and 6 powders. The key underlying parameters are shown in the table above.
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>> | 64% | 18,985 psi | 87% | 889 fps | 99% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 64% | 18,231 psi | 84% | 827 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 18,565 psi | 85% | 794 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 17,492 psi | 80% | 801 fps | 100% |
| Rottweil P 806*² | <<locked>> | 64% | 19,276 psi | 89% | 968 fps | 92.1% |
| Vihtavuori N32C Tin Star² | <<locked>> | 72% | 19,377 psi | 89% | 791 fps | 100% |
Start Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 60% | 16,853 psi | 77% | 846 fps | 98.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 16,520 psi | 76% | 797 fps | 100% |
| Hodgdon TrailBoss² | <<locked>> | 60% | 9,558 psi | 44% | 604 fps | 100% |
| ReloadSwiss RS 14² | <<locked>> | 60% | 9,007 psi | 41% | 597 fps | 99.7% |
| Rottweil P 806*² | <<locked>> | 60% | 16,752 psi | 77% | 915 fps | 89.6% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 14,620 psi | 67% | 709 fps | 100% |
* 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 6 powders for .38 Special loaded with the .357 | 158gr | Zero JHP. Rottweil P 806 delivers the highest muzzle velocity at 968 fps; across all powders the maximum-charge window runs from 791 fps to 968 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 6 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 80–89 %, 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. As outliers, Rottweil P 806 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.