Load Specifications
Load data in caliber .357 Auto Mag. with .357 | 125gr | Sierra JSP FN 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% | 32,343 psi | 87% | 1447 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 68% | 32,996 psi | 89% | 1519 fps | 100% |
| Accurate TCM*² | <<locked>> | 68% | 29,588 psi | 80% | 1650 fps | 88.4% |
| ADI AP 100 | <<locked>> | 80% | 31,531 psi | 85% | 1647 fps | 99.4% |
| ADI APS 350² | <<locked>> | 64% | 33,286 psi | 90% | 1352 fps | 100% |
| ADI APS 450² | <<locked>> | 64% | 32,068 psi | 87% | 1368 fps | 100% |
| ADI AS 30² | <<locked>> | 64% | 31,995 psi | 87% | 1407 fps | 100% |
| Alliant BE-86² | <<locked>> | 64% | 30,414 psi | 82% | 1460 fps | 100% |
| Alliant BLUE DOT* | <<locked>> | 80% | 30,690 psi | 83% | 1673 fps | 92% |
| Alliant Green Dot² | <<locked>> | 64% | 32,256 psi | 87% | 1463 fps | 100% |
| Alliant Herco | <<locked>> | 80% | 33,025 psi | 89% | 1594 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 64% | 30,472 psi | 82% | 1670 fps | 98.7% |
| Alliant RED DOT² | <<locked>> | 64% | 31,096 psi | 84% | 1414 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 64% | 30,487 psi | 82% | 1558 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 64% | 32,271 psi | 87% | 1450 fps | 100% |
| Baschieri & Pellagri 102 Pistol | <<locked>> | 80% | 32,227 psi | 87% | 1457 fps | 100% |
| Hodgdon Clays² | <<locked>> | 72% | 32,401 psi | 88% | 1368 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 21,103 psi | 57% | 1214 fps | 100% |
| Maxam CSB 1² | <<locked>> | 68% | 30,821 psi | 83% | 1480 fps | 100% |
| Maxam CSB 2² | <<locked>> | 64% | 31,154 psi | 84% | 1476 fps | 100% |
| Maxam CSB 3² | <<locked>> | 64% | 30,908 psi | 84% | 1453 fps | 100% |
| Maxam CSB 4² | <<locked>> | 64% | 32,619 psi | 88% | 1457 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 19,508 psi | 53% | 1220 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 68% | 32,808 psi | 89% | 1585 fps | 100% |
| ReloadSwiss RS 24² | <<locked>> | 68% | 32,039 psi | 87% | 1703 fps | 95.8% |
| Rottweil P 806² | <<locked>> | 72% | 33,417 psi | 90% | 1716 fps | 100% |
| SNPE Vectan A0² | <<locked>> | 68% | 31,140 psi | 84% | 1526 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 64% | 32,996 psi | 89% | 1522 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 72% | 30,806 psi | 83% | 1588 fps | 100% |
| SNPE Vectan BA9 1/2² | <<locked>> | 64% | 32,561 psi | 88% | 1519 fps | 100% |
| Somchem MS200² | <<locked>> | 64% | 31,009 psi | 84% | 1535 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 68% | 33,011 psi | 89% | 1640 fps | 100% |
| Vihtavuori 3N38 | <<locked>> | 80% | 32,518 psi | 88% | 1696 fps | 96.7% |
| Vihtavuori N105 | <<locked>> | 84% | 33,011 psi | 89% | 1752 fps | 99.2% |
| Vihtavuori N32C Tin Star | <<locked>> | 92% | 32,880 psi | 89% | 1381 fps | 100% |
| Vihtavuori N340² | <<locked>> | 64% | 31,183 psi | 84% | 1542 fps | 100% |
| Vihtavuori N350² | <<locked>> | 72% | 32,329 psi | 87% | 1624 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 68% | 32,532 psi | 88% | 1526 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% | 29,588 psi | 80% | 1404 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 60% | 26,165 psi | 71% | 1407 fps | 100% |
| Accurate TCM*² | <<locked>> | 64% | 25,556 psi | 69% | 1562 fps | 85.6% |
| ADI AP 100*² | <<locked>> | 60% | 18,057 psi | 49% | 1325 fps | 93.1% |
| ADI APS 350² | <<locked>> | 60% | 30,356 psi | 82% | 1306 fps | 100% |
| ADI APS 450² | <<locked>> | 60% | 28,848 psi | 78% | 1316 fps | 100% |
| ADI AS 30² | <<locked>> | 60% | 29,196 psi | 79% | 1362 fps | 100% |
| Alliant BE-86² | <<locked>> | 60% | 27,180 psi | 73% | 1407 fps | 100% |
| Alliant BLUE DOT*² | <<locked>> | 68% | 21,886 psi | 59% | 1463 fps | 85.7% |
| Alliant Green Dot² | <<locked>> | 60% | 29,037 psi | 79% | 1411 fps | 100% |
| Alliant Herco² | <<locked>> | 60% | 19,725 psi | 53% | 1329 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 60% | 26,542 psi | 72% | 1581 fps | 97.4% |
| Alliant RED DOT² | <<locked>> | 60% | 28,311 psi | 77% | 1365 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 60% | 27,093 psi | 73% | 1496 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 60% | 28,500 psi | 77% | 1391 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 19,189 psi | 52% | 1227 fps | 100% |
| Hodgdon Clays² | <<locked>> | 60% | 24,729 psi | 67% | 1243 fps | 100% |
| Hodgdon TrailBoss² | 5.3 gr | 60% | 9,631 psi | 26% | 909 fps | 100% |
| Maxam CSB 1² | <<locked>> | 60% | 25,019 psi | 68% | 1378 fps | 100% |
| Maxam CSB 2² | <<locked>> | 60% | 27,557 psi | 75% | 1417 fps | 100% |
| Maxam CSB 3² | <<locked>> | 60% | 27,789 psi | 75% | 1404 fps | 100% |
| Maxam CSB 4² | <<locked>> | 60% | 29,341 psi | 79% | 1407 fps | 100% |
| ReloadSwiss RS 14² | 5.4 gr | 60% | 9,108 psi | 25% | 912 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 25,889 psi | 70% | 1467 fps | 100% |
| ReloadSwiss RS 24*² | <<locked>> | 60% | 24,497 psi | 66% | 1535 fps | 91.7% |
| Rottweil P 806² | <<locked>> | 60% | 21,799 psi | 59% | 1480 fps | 98.9% |
| SNPE Vectan A0² | <<locked>> | 60% | 24,714 psi | 67% | 1411 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 60% | 29,544 psi | 80% | 1470 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 60% | 21,756 psi | 59% | 1398 fps | 99.2% |
| SNPE Vectan BA9 1/2² | <<locked>> | 60% | 29,008 psi | 78% | 1463 fps | 100% |
| Somchem MS200² | <<locked>> | 60% | 27,615 psi | 75% | 1473 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 60% | 25,831 psi | 70% | 1509 fps | 100% |
| Vihtavuori 3N38*² | <<locked>> | 60% | 17,405 psi | 47% | 1329 fps | 86.3% |
| Vihtavuori N105*² | <<locked>> | 60% | 14,794 psi | 40% | 1296 fps | 87.1% |
| Vihtavuori N32C Tin Star² | 7.2 gr | 60% | 16,331 psi | 44% | 1086 fps | 100% |
| Vihtavuori N340² | <<locked>> | 60% | 27,209 psi | 74% | 1470 fps | 100% |
| Vihtavuori N350² | <<locked>> | 60% | 22,205 psi | 60% | 1427 fps | 99.8% |
| Winchester AutoComp ² | <<locked>> | 60% | 25,875 psi | 70% | 1414 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 .357 | 125gr | Sierra JSP FN. Vihtavuori N105 delivers the highest muzzle velocity at 1,752 fps; across all powders the maximum-charge window runs from 1,214 fps to 1,752 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 .357 | 125gr | Sierra JSP FN 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.