Load Specifications
Load data in caliber .38 Special with .355 | 124gr | Speer TMJ bullet and 14 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.
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Max Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 68% | 18,420 psi | 85% | 1033 fps | 96.7% |
| Alliant Herco² | <<locked>> | 68% | 19,334 psi | 89% | 1060 fps | 97.4% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 68% | 17,782 psi | 82% | 974 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 68% | 18,855 psi | 87% | 1001 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 16,143 psi | 74% | 906 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 16,955 psi | 78% | 925 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 14,794 psi | 68% | 902 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 15,490 psi | 71% | 922 fps | 100% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 18,173 psi | 84% | 1027 fps | 88.8% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 18,869 psi | 87% | 1050 fps | 89.8% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 18,579 psi | 85% | 938 fps | 100% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 19,406 psi | 89% | 955 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 17,941 psi | 82% | 1040 fps | 90% |
| Vihtavuori N350*² | <<locked>> | 64% | 18,840 psi | 87% | 1063 fps | 91.2% |
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% | 14,924 psi | 69% | 948 fps | 93.7% |
| Alliant Herco*² | <<locked>> | 60% | 15,476 psi | 71% | 965 fps | 94.5% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 14,489 psi | 67% | 906 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 15,142 psi | 70% | 922 fps | 100% |
| Hodgdon TrailBoss² | 3.5 gr | 60% | 7,455 psi | 34% | 663 fps | 98.8% |
| Hodgdon TrailBoss² | 3.5 gr | 60% | 7,673 psi | 35% | 673 fps | 99.1% |
| ReloadSwiss RS 14*² | 3.6 gr | 60% | 7,107 psi | 33% | 656 fps | 94.9% |
| ReloadSwiss RS 14² | 3.6 gr | 60% | 7,324 psi | 34% | 666 fps | 95.6% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 16,012 psi | 74% | 971 fps | 86.2% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 16,766 psi | 77% | 997 fps | 87.5% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 12,604 psi | 58% | 814 fps | 100% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 13,111 psi | 60% | 830 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 16,099 psi | 74% | 994 fps | 88% |
| Vihtavuori N350*² | <<locked>> | 60% | 16,592 psi | 76% | 1007 fps | 88.8% |
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 4 powders for .38 Special loaded with the .355 | 124gr | Speer TMJ. Hodgdon TrailBoss delivers the highest muzzle velocity at 925 fps; across all powders the maximum-charge window runs from 902 fps to 925 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 4 of the 4 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 68–78 %, leaving at least 22 % headroom. Hodgdon TrailBoss, 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 .355 | 124gr | Speer TMJ they combine a high case fill with complete burn and sit in the upper velocity band. Hodgdon TrailBoss, 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.