Load Specifications
Load data in caliber .38 Special with .358 | 130gr | Rim Rock RNFP Cowboy bullet and 8 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% | 19,189 psi | 88% | 1030 fps | 97.8% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 68% | 19,102 psi | 88% | 978 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 16,984 psi | 78% | 899 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 15,592 psi | 72% | 896 fps | 100% |
| Rottweil P 806*² | <<locked>> | 68% | 19,406 psi | 89% | 1096 fps | 88.8% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 19,276 psi | 89% | 1030 fps | 90.9% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 19,493 psi | 90% | 928 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 64% | 19,247 psi | 88% | 1047 fps | 92.3% |
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% | 15,635 psi | 72% | 945 fps | 95.3% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 15,273 psi | 70% | 899 fps | 100% |
| Hodgdon TrailBoss² | 3.4 gr | 60% | 7,774 psi | 36% | 656 fps | 99.5% |
| ReloadSwiss RS 14² | 3.5 gr | 60% | 7,411 psi | 34% | 653 fps | 96.3% |
| Rottweil P 806*² | <<locked>> | 64% | 17,056 psi | 78% | 1040 fps | 86% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 17,085 psi | 79% | 978 fps | 88.6% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 13,445 psi | 62% | 814 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 16,882 psi | 78% | 991 fps | 90% |
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 | 130gr | Rim Rock RNFP Cowboy. Hodgdon TrailBoss delivers the highest muzzle velocity at 899 fps; across all powders the maximum-charge window runs from 896 fps to 899 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 72–78 %, leaving at least 22 % 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 | 130gr | Rim Rock RNFP 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.