Load Specifications
Load data in caliber .38 Special with .357 | 158gr | Frontier Bullets FP bullet and 6 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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AP 100*² | <<locked>> | 68% | 19,580 psi | 90% | 932 fps | 88.3% |
| Alliant Herco² | <<locked>> | 64% | 19,624 psi | 90% | 909 fps | 99.4% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 64% | 19,551 psi | 90% | 856 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 19,450 psi | 89% | 814 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 18,391 psi | 85% | 823 fps | 100% |
| Vihtavuori N32C Tin Star² | <<locked>> | 68% | 18,608 psi | 86% | 784 fps | 100% |
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>> | 64% | 17,651 psi | 81% | 889 fps | 86.3% |
| Alliant Herco² | <<locked>> | 60% | 18,086 psi | 83% | 879 fps | 98.9% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 17,347 psi | 80% | 817 fps | 100% |
| Hodgdon TrailBoss² | 3 gr | 60% | 9,790 psi | 45% | 614 fps | 100% |
| ReloadSwiss RS 14² | 3 gr | 60% | 9,239 psi | 42% | 610 fps | 99.9% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 15,751 psi | 72% | 738 fps | 100% |
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 2 powders for .38 Special loaded with the .357 | 158gr | Frontier Bullets FP. ReloadSwiss RS 14 delivers the highest muzzle velocity at 823 fps; across all powders the maximum-charge window runs from 814 fps to 823 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 2 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 85–89 %, 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. ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .38 Special with the .357 | 158gr | Frontier Bullets FP they combine a high case fill with complete burn and sit in the upper velocity band. Hodgdon TrailBoss, ReloadSwiss RS 14 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.