Load Specifications
Load data in caliber .357 Auto Mag. with .355 | 125gr | Speer TMJ bullet and 38 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N32C Tin Star, ReloadSwiss RS 14 and Hodgdon TrailBoss.
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: 6.5"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate Solo 1000² | <<locked>> | 64% | 32,547 psi | 88% | 1453 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 68% | 33,199 psi | 90% | 1522 fps | 100% |
| Accurate TCM*² | <<locked>> | 68% | 29,588 psi | 80% | 1650 fps | 88.5% |
| ADI AP 100 | <<locked>> | 80% | 32,068 psi | 87% | 1660 fps | 99.5% |
| ADI APS 350² | <<locked>> | 64% | 32,938 psi | 89% | 1348 fps | 100% |
| ADI APS 450² | <<locked>> | 64% | 32,300 psi | 87% | 1371 fps | 100% |
| ADI AS 30² | <<locked>> | 64% | 32,213 psi | 87% | 1411 fps | 100% |
| Alliant BE-86² | <<locked>> | 64% | 30,545 psi | 83% | 1463 fps | 100% |
| Alliant BLUE DOT* | <<locked>> | 80% | 31,169 psi | 84% | 1686 fps | 92.4% |
| Alliant Green Dot² | <<locked>> | 64% | 32,474 psi | 88% | 1470 fps | 100% |
| Alliant Herco | <<locked>> | 80% | 33,098 psi | 89% | 1594 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 64% | 30,560 psi | 83% | 1670 fps | 98.8% |
| Alliant RED DOT² | <<locked>> | 64% | 31,357 psi | 85% | 1421 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 64% | 30,632 psi | 83% | 1562 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 64% | 32,489 psi | 88% | 1457 fps | 100% |
| Baschieri & Pellagri 102 Pistol | <<locked>> | 80% | 32,329 psi | 87% | 1460 fps | 100% |
| Hodgdon Clays² | <<locked>> | 72% | 32,068 psi | 87% | 1365 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 20,900 psi | 57% | 1211 fps | 100% |
| Maxam CSB 1² | <<locked>> | 68% | 31,024 psi | 84% | 1483 fps | 100% |
| Maxam CSB 2² | <<locked>> | 64% | 30,850 psi | 83% | 1473 fps | 100% |
| Maxam CSB 3² | <<locked>> | 64% | 31,125 psi | 84% | 1460 fps | 100% |
| Maxam CSB 4² | <<locked>> | 64% | 32,837 psi | 89% | 1463 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 19,682 psi | 53% | 1224 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 68% | 32,982 psi | 89% | 1588 fps | 100% |
| ReloadSwiss RS 24² | <<locked>> | 68% | 32,126 psi | 87% | 1703 fps | 95.9% |
| Rottweil P 806² | <<locked>> | 68% | 29,414 psi | 80% | 1647 fps | 100% |
| SNPE Vectan A0² | <<locked>> | 68% | 31,299 psi | 85% | 1532 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 64% | 33,127 psi | 90% | 1526 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 72% | 30,864 psi | 83% | 1591 fps | 100% |
| SNPE Vectan BA9 1/2² | <<locked>> | 64% | 32,721 psi | 88% | 1526 fps | 100% |
| Somchem MS200² | <<locked>> | 64% | 31,183 psi | 84% | 1539 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 68% | 33,141 psi | 90% | 1644 fps | 100% |
| Vihtavuori 3N38 | <<locked>> | 80% | 32,996 psi | 89% | 1709 fps | 96.9% |
| Vihtavuori N105 | <<locked>> | 80% | 29,298 psi | 79% | 1683 fps | 98.3% |
| Vihtavuori N32C Tin Star | <<locked>> | 92% | 33,025 psi | 89% | 1385 fps | 100% |
| Vihtavuori N340² | <<locked>> | 64% | 31,328 psi | 85% | 1545 fps | 100% |
| Vihtavuori N350² | <<locked>> | 72% | 32,416 psi | 88% | 1627 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 68% | 32,648 psi | 88% | 1529 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 6.5"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate Solo 1000² | <<locked>> | 60% | 29,298 psi | 79% | 1401 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 60% | 26,368 psi | 71% | 1411 fps | 100% |
| Accurate TCM*² | <<locked>> | 64% | 25,599 psi | 69% | 1565 fps | 85.7% |
| ADI AP 100*² | <<locked>> | 60% | 18,144 psi | 49% | 1332 fps | 93.2% |
| ADI APS 350² | <<locked>> | 60% | 30,052 psi | 81% | 1302 fps | 100% |
| ADI APS 450² | <<locked>> | 60% | 29,066 psi | 79% | 1322 fps | 100% |
| ADI AS 30² | <<locked>> | 60% | 28,906 psi | 78% | 1358 fps | 100% |
| Alliant BE-86² | <<locked>> | 60% | 27,340 psi | 74% | 1414 fps | 100% |
| Alliant BLUE DOT*² | <<locked>> | 68% | 21,930 psi | 59% | 1467 fps | 85.8% |
| Alliant Green Dot² | <<locked>> | 60% | 29,254 psi | 79% | 1414 fps | 100% |
| Alliant Herco² | <<locked>> | 60% | 19,870 psi | 54% | 1332 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 60% | 26,672 psi | 72% | 1588 fps | 97.5% |
| Alliant RED DOT² | <<locked>> | 60% | 28,036 psi | 76% | 1362 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 60% | 27,267 psi | 74% | 1499 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 60% | 28,718 psi | 78% | 1394 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 19,363 psi | 52% | 1230 fps | 100% |
| Hodgdon Clays² | <<locked>> | 60% | 24,497 psi | 66% | 1240 fps | 100% |
| Hodgdon TrailBoss² | 5.4 gr | 60% | 9,805 psi | 27% | 915 fps | 100% |
| Maxam CSB 1² | <<locked>> | 60% | 24,772 psi | 67% | 1375 fps | 100% |
| Maxam CSB 2² | <<locked>> | 60% | 27,760 psi | 75% | 1424 fps | 100% |
| Maxam CSB 3² | <<locked>> | 60% | 28,021 psi | 76% | 1407 fps | 100% |
| Maxam CSB 4² | <<locked>> | 60% | 29,573 psi | 80% | 1411 fps | 100% |
| ReloadSwiss RS 14² | 5.5 gr | 60% | 9,282 psi | 25% | 922 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 26,049 psi | 70% | 1470 fps | 100% |
| ReloadSwiss RS 24*² | <<locked>> | 60% | 24,598 psi | 67% | 1535 fps | 91.7% |
| Rottweil P 806² | <<locked>> | 60% | 21,872 psi | 59% | 1480 fps | 98.9% |
| SNPE Vectan A0² | <<locked>> | 60% | 24,889 psi | 67% | 1417 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 60% | 29,211 psi | 79% | 1463 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 60% | 21,886 psi | 59% | 1404 fps | 99.2% |
| SNPE Vectan BA9 1/2² | <<locked>> | 60% | 29,167 psi | 79% | 1467 fps | 100% |
| Somchem MS200² | <<locked>> | 60% | 27,775 psi | 75% | 1480 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 60% | 25,976 psi | 70% | 1512 fps | 100% |
| Vihtavuori 3N38*² | <<locked>> | 60% | 17,521 psi | 47% | 1335 fps | 86.5% |
| Vihtavuori N105*² | <<locked>> | 60% | 14,910 psi | 40% | 1299 fps | 87.3% |
| Vihtavuori N32C Tin Star² | 7.3 gr | 60% | 16,534 psi | 45% | 1093 fps | 100% |
| Vihtavuori N340² | <<locked>> | 60% | 27,398 psi | 74% | 1476 fps | 100% |
| Vihtavuori N350² | <<locked>> | 60% | 22,365 psi | 60% | 1430 fps | 99.8% |
| Winchester AutoComp ² | <<locked>> | 60% | 26,020 psi | 70% | 1417 fps | 100% |
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 38 powders for .357 Auto Mag. loaded with the .355 | 125gr | Speer TMJ. Vihtavuori 3N38 delivers the highest muzzle velocity at 1,709 fps; across all powders the maximum-charge window runs from 1,211 fps to 1,709 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 9 of the 38 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (255 MPa), the top charges use 53–90 %, leaving at least 10 % 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. Vihtavuori N32C Tin Star, ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .357 Auto Mag. with the .355 | 125gr | Speer TMJ they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate TCM, Alliant BLUE DOT burn incompletely and react more sensitively to barrel length and temperature. Hodgdon TrailBoss, ReloadSwiss RS 14, Vihtavuori N32C Tin Star 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.