Load Specifications
Load data in caliber .38 Special with .356 | 120gr | LEE Mold 356-120-TC bullet and 7 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 Herco² | <<locked>> | 72% | 19,638 psi | 90% | 1096 fps | 97.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 72% | 19,551 psi | 90% | 1040 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 15,214 psi | 70% | 922 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 13,895 psi | 64% | 915 fps | 100% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 17,564 psi | 81% | 1043 fps | 87.7% |
| Vihtavuori N32C Tin Star | <<locked>> | 80% | 19,116 psi | 88% | 984 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 17,477 psi | 80% | 1056 fps | 89% |
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% | 13,663 psi | 63% | 938 fps | 91.5% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 13,518 psi | 62% | 909 fps | 100% |
| Hodgdon TrailBoss² | 3.6 gr | 60% | 6,324 psi | 29% | 650 fps | 96.3% |
| ReloadSwiss RS 14*² | 3.7 gr | 60% | 5,773 psi | 27% | 630 fps | 89.9% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 15,534 psi | 71% | 991 fps | 85.2% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 11,443 psi | 53% | 817 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 15,258 psi | 70% | 997 fps | 86.2% |
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 7 powders for .38 Special loaded with the .356 | 120gr | LEE Mold 356-120-TC. Alliant Herco delivers the highest muzzle velocity at 1,096 fps; across all powders the maximum-charge window runs from 915 fps to 1,096 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 3 of the 7 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 64–90 %, 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 .356 | 120gr | LEE Mold 356-120-TC they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, 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.