Load Specifications
Load data in caliber .38 Special with .357 | 170gr | Sierra FMJ RN SportsMaster 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% | 19,203 psi | 88% | 883 fps | 88.2% |
| Alliant Herco² | <<locked>> | 68% | 19,029 psi | 87% | 863 fps | 99.4% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 68% | 19,014 psi | 87% | 814 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 17,202 psi | 79% | 748 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 15,316 psi | 70% | 741 fps | 100% |
| Rottweil P 806*² | <<locked>> | 68% | 18,971 psi | 87% | 935 fps | 92.8% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 64% | 19,043 psi | 88% | 866 fps | 93.9% |
| Vihtavuori N32C Tin Star² | <<locked>> | 76% | 19,334 psi | 89% | 764 fps | 100% |
| Vihtavuori N350² | <<locked>> | 64% | 18,710 psi | 86% | 873 fps | 95% |
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% | 17,492 psi | 80% | 850 fps | 86.5% |
| Alliant Herco² | <<locked>> | 60% | 15,592 psi | 72% | 794 fps | 97.7% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 15,243 psi | 70% | 751 fps | 100% |
| Hodgdon TrailBoss² | 2.6 gr | 60% | 7,760 psi | 36% | 548 fps | 100% |
| ReloadSwiss RS 14² | 2.7 gr | 60% | 7,484 psi | 34% | 551 fps | 98.6% |
| Rottweil P 806*² | <<locked>> | 60% | 14,359 psi | 66% | 837 fps | 87.5% |
| SNPE Vectan BA7 1/2*² | <<locked>> | 60% | 16,781 psi | 77% | 820 fps | 91.8% |
| Vihtavuori N32C Tin Star² | <<locked>> | 60% | 12,850 psi | 59% | 663 fps | 100% |
| Vihtavuori N350*² | <<locked>> | 60% | 16,868 psi | 78% | 840 fps | 93.5% |
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 9 powders for .38 Special loaded with the .357 | 170gr | Sierra FMJ RN SportsMaster. Rottweil P 806 delivers the highest muzzle velocity at 935 fps; across all powders the maximum-charge window runs from 741 fps to 935 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 9 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (150 MPa), the top charges use 70–89 %, 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. Hodgdon TrailBoss, ReloadSwiss RS 14 rank at the top here: for .38 Special with the .357 | 170gr | Sierra FMJ RN SportsMaster they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AP 100, Rottweil P 806, SNPE Vectan BA7 1/2 burn incompletely and react more sensitively to barrel length and temperature. ADI AP 100, Alliant Herco, Baschieri & Pellagri 102 Pistol 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.