Load Specifications
Load data in caliber .38 Special with .355 | 124gr | X-TREME FP bullet and 6 powders. The key underlying parameters are shown in the table above.
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>> | 64% | 19,189 psi | 88% | 1040 fps | 97.5% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 64% | 18,434 psi | 85% | 978 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 18,434 psi | 85% | 938 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 17,738 psi | 82% | 951 fps | 100% |
| Rottweil P 806*² | <<locked>> | 64% | 19,305 psi | 89% | 1109 fps | 88.3% |
| Vihtavuori N32C Tin Star² | <<locked>> | 72% | 19,435 psi | 89% | 938 fps | 100% |
Start Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Herco² | <<locked>> | 60% | 17,071 psi | 78% | 991 fps | 96.2% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 16,650 psi | 77% | 942 fps | 100% |
| Hodgdon TrailBoss² | <<locked>> | 60% | 9,398 psi | 43% | 709 fps | 100% |
| ReloadSwiss RS 14² | <<locked>> | 60% | 9,152 psi | 42% | 709 fps | 98.8% |
| Rottweil P 806*² | <<locked>> | 60% | 16,969 psi | 78% | 1050 fps | 85.6% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 15,127 psi | 70% | 853 fps | 100% |
* 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 6 powders for .38 Special loaded with the .355 | 124gr | X-TREME FP. Rottweil P 806 delivers the highest muzzle velocity at 1,109 fps; across all powders the maximum-charge window runs from 938 fps to 1,109 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 6 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 82–89 %, 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. As outliers, Rottweil P 806 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.