Load Specifications
Load data in caliber .38 Special with .355 | 121gr | Frontier Bullets CMJ FP atch bullet and 5 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.
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Max Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 64% | 19,029 psi | 87% | 1053 fps | 97.3% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 64% | 18,318 psi | 84% | 991 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 18,376 psi | 84% | 951 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 17,680 psi | 81% | 965 fps | 100% |
| Vihtavuori N32C Tin Star² | <<locked>> | 72% | 19,363 psi | 89% | 951 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 |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 60% | 16,940 psi | 78% | 1001 fps | 95.8% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 16,578 psi | 76% | 951 fps | 100% |
| Hodgdon TrailBoss² | 3.6 gr | 60% | 9,500 psi | 44% | 722 fps | 100% |
| ReloadSwiss RS 14² | 3.6 gr | 60% | 8,949 psi | 41% | 712 fps | 98.4% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 14,721 psi | 68% | 856 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
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 5 powders for .38 Special loaded with the .355 | 121gr | Frontier Bullets CMJ FP atch. Alliant Herco delivers the highest muzzle velocity at 1,053 fps; across all powders the maximum-charge window runs from 951 fps to 1,053 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 5 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 81–89 %, 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 .355 | 121gr | Frontier Bullets CMJ FP atch they combine a high case fill with complete burn and sit in the upper velocity band. 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.