Load Specifications
Load data in caliber .38 Special with .358 | 158gr | Rim Rock RN Cowboy 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.
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Max Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AP 100*² | <<locked>> | 72% | 19,508 psi | 90% | 935 fps | 87.7% |
| Alliant Herco² | <<locked>> | 68% | 19,218 psi | 88% | 912 fps | 99.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 68% | 18,753 psi | 86% | 853 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 17,347 psi | 80% | 794 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 15,983 psi | 73% | 794 fps | 100% |
| Rottweil P 806*² | <<locked>> | 68% | 19,363 psi | 89% | 988 fps | 92.1% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 18,913 psi | 87% | 909 fps | 93.1% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 19,435 psi | 89% | 810 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 19,276 psi | 89% | 932 fps | 94.8% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AP 100*² | <<locked>> | 68% | 17,419 psi | 80% | 892 fps | 85.5% |
| Alliant Herco² | <<locked>> | 60% | 15,505 psi | 71% | 833 fps | 97.1% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 15,316 psi | 70% | 791 fps | 100% |
| Hodgdon TrailBoss² | 2.9 gr | 60% | 8,064 psi | 37% | 587 fps | 100% |
| ReloadSwiss RS 14² | 2.9 gr | 60% | 7,382 psi | 34% | 577 fps | 98.1% |
| Rottweil P 806*² | <<locked>> | 60% | 14,634 psi | 67% | 879 fps | 86.5% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 16,868 psi | 78% | 866 fps | 91.1% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 13,416 psi | 62% | 709 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 16,984 psi | 78% | 886 fps | 92.9% |
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 2 powders for .38 Special loaded with the .358 | 158gr | Rim Rock RN Cowboy. Hodgdon TrailBoss delivers the highest muzzle velocity at 794 fps; across all powders the maximum-charge window runs from 794 fps to 794 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 2 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 73–80 %, leaving at least 20 % 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 | 158gr | Rim Rock RN Cowboy they combine a high case fill with complete burn and sit in the upper velocity band. 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.