Load Specifications
Load data in caliber .38 Special with .358 | 105gr | LEE Mold 358-105-SWC 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.
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 |
|---|---|---|---|---|---|---|
| Alliant Herco*² | <<locked>> | 72% | 18,159 psi | 83% | 1135 fps | 94.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 72% | 17,637 psi | 81% | 1083 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 14,185 psi | 65% | 971 fps | 100% |
| Maxam CSB 1² | <<locked>> | 64% | 19,493 psi | 90% | 1138 fps | 99.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 12,459 psi | 57% | 942 fps | 99% |
| ReloadSwiss RS 20² | <<locked>> | 64% | 18,913 psi | 87% | 1175 fps | 96.8% |
| SNPE Vectan A0² | <<locked>> | 64% | 19,363 psi | 89% | 1142 fps | 95.3% |
| Vihtavuori N32C Tin Star | <<locked>> | 84% | 19,392 psi | 89% | 1070 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 64% | 19,638 psi | 90% | 1152 fps | 98.8% |
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 Herco*² | <<locked>> | 60% | 12,647 psi | 58% | 974 fps | 87.5% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 12,517 psi | 58% | 951 fps | 99.3% |
| Hodgdon TrailBoss*² | 3.7 gr | 60% | 5,947 psi | 27% | 679 fps | 93.1% |
| Maxam CSB 1² | <<locked>> | 60% | 16,911 psi | 78% | 1076 fps | 98.4% |
| ReloadSwiss RS 14*² | 4 gr | 64% | 5,845 psi | 27% | 682 fps | 87.3% |
| ReloadSwiss RS 20*² | <<locked>> | 60% | 16,447 psi | 76% | 1106 fps | 94.7% |
| SNPE Vectan A0*² | <<locked>> | 60% | 17,419 psi | 80% | 1093 fps | 93.7% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 10,254 psi | 47% | 850 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 60% | 17,347 psi | 80% | 1093 fps | 97.6% |
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 | 105gr | LEE Mold 358-105-SWC. ReloadSwiss RS 20 delivers the highest muzzle velocity at 1,175 fps; across all powders the maximum-charge window runs from 942 fps to 1,175 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 3 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 57–90 %, 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. Hodgdon TrailBoss, ReloadSwiss RS 14 rank at the top here: for .38 Special with the .358 | 105gr | LEE Mold 358-105-SWC they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Herco 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.