Load Specifications
Load data in caliber .357 Auto Mag. with .358 | 125gr | Rim Rock TC Cowboy bullet and 41 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 No. 7*² | <<locked>> | 64% | 33,286 psi | 90% | 1736 fps | 94.3% |
| Accurate Solo 1000² | <<locked>> | 64% | 32,706 psi | 88% | 1450 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 68% | 32,822 psi | 89% | 1516 fps | 100% |
| Accurate TCM*² | <<locked>> | 68% | 29,254 psi | 79% | 1640 fps | 88.1% |
| ADI AP 100 | <<locked>> | 80% | 31,502 psi | 85% | 1644 fps | 99.4% |
| ADI APS 350² | <<locked>> | 64% | 33,040 psi | 89% | 1345 fps | 100% |
| ADI APS 450² | <<locked>> | 64% | 31,879 psi | 86% | 1362 fps | 100% |
| ADI AS 30² | <<locked>> | 64% | 31,763 psi | 86% | 1401 fps | 100% |
| Alliant BE-86² | <<locked>> | 64% | 30,284 psi | 82% | 1457 fps | 100% |
| Alliant BLUE DOT* | <<locked>> | 80% | 30,705 psi | 83% | 1677 fps | 92.1% |
| Alliant Green Dot² | <<locked>> | 64% | 32,039 psi | 87% | 1457 fps | 100% |
| Alliant Herco | <<locked>> | 80% | 32,953 psi | 89% | 1588 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 64% | 29,892 psi | 81% | 1654 fps | 98.5% |
| Alliant RED DOT² | <<locked>> | 64% | 30,835 psi | 83% | 1407 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 68% | 33,417 psi | 90% | 1604 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 64% | 32,097 psi | 87% | 1447 fps | 100% |
| Baschieri & Pellagri 102 Pistol | <<locked>> | 80% | 31,647 psi | 86% | 1447 fps | 100% |
| Hodgdon Clays² | <<locked>> | 72% | 32,227 psi | 87% | 1365 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 20,943 psi | 57% | 1207 fps | 100% |
| Lovex D037.1*² | <<locked>> | 64% | 33,286 psi | 90% | 1736 fps | 94.3% |
| Maxam CSB 1² | <<locked>> | 68% | 30,661 psi | 83% | 1473 fps | 100% |
| Maxam CSB 2² | <<locked>> | 64% | 30,951 psi | 84% | 1473 fps | 100% |
| Maxam CSB 3² | <<locked>> | 64% | 30,705 psi | 83% | 1450 fps | 100% |
| Maxam CSB 4² | <<locked>> | 64% | 32,445 psi | 88% | 1453 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 19,725 psi | 53% | 1224 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 68% | 32,663 psi | 88% | 1581 fps | 100% |
| ReloadSwiss RS 24² | <<locked>> | 68% | 31,604 psi | 85% | 1690 fps | 95.5% |
| Rottweil P 806² | <<locked>> | 72% | 33,040 psi | 89% | 1709 fps | 100% |
| Shooters World Major Pistol*² | <<locked>> | 64% | 33,286 psi | 90% | 1736 fps | 94.3% |
| SNPE Vectan A0² | <<locked>> | 68% | 31,024 psi | 84% | 1522 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 64% | 32,837 psi | 89% | 1519 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 72% | 30,734 psi | 83% | 1585 fps | 100% |
| SNPE Vectan BA9 1/2² | <<locked>> | 64% | 32,416 psi | 88% | 1516 fps | 100% |
| Somchem MS200² | <<locked>> | 64% | 30,864 psi | 83% | 1529 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 68% | 32,953 psi | 89% | 1640 fps | 100% |
| Vihtavuori 3N38 | <<locked>> | 80% | 32,503 psi | 88% | 1693 fps | 96.6% |
| Vihtavuori N105 | <<locked>> | 84% | 32,474 psi | 88% | 1739 fps | 99.1% |
| Vihtavuori N32C Tin Star | <<locked>> | 92% | 32,750 psi | 89% | 1378 fps | 100% |
| Vihtavuori N340² | <<locked>> | 64% | 30,501 psi | 82% | 1529 fps | 100% |
| Vihtavuori N350² | <<locked>> | 72% | 32,227 psi | 87% | 1621 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 68% | 32,416 psi | 88% | 1522 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 No. 7*² | <<locked>> | 60% | 28,645 psi | 77% | 1640 fps | 91.9% |
| Accurate Solo 1000² | <<locked>> | 60% | 29,385 psi | 79% | 1398 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 60% | 26,469 psi | 72% | 1411 fps | 100% |
| Accurate TCM*² | <<locked>> | 64% | 25,251 psi | 68% | 1552 fps | 85.2% |
| ADI AP 100*² | <<locked>> | 60% | 17,941 psi | 49% | 1322 fps | 92.9% |
| ADI APS 350² | <<locked>> | 60% | 30,095 psi | 81% | 1299 fps | 100% |
| ADI APS 450² | <<locked>> | 60% | 29,182 psi | 79% | 1319 fps | 100% |
| ADI AS 30² | <<locked>> | 60% | 28,950 psi | 78% | 1355 fps | 100% |
| Alliant BE-86² | <<locked>> | 60% | 27,050 psi | 73% | 1404 fps | 100% |
| Alliant BLUE DOT*² | <<locked>> | 68% | 21,509 psi | 58% | 1453 fps | 85.4% |
| Alliant Green Dot² | <<locked>> | 60% | 28,790 psi | 78% | 1404 fps | 100% |
| Alliant Herco² | <<locked>> | 60% | 19,580 psi | 53% | 1322 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 60% | 26,411 psi | 71% | 1575 fps | 97.3% |
| Alliant RED DOT² | <<locked>> | 60% | 28,021 psi | 76% | 1358 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 60% | 26,905 psi | 73% | 1490 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 60% | 28,834 psi | 78% | 1394 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 19,029 psi | 51% | 1224 fps | 100% |
| Hodgdon Clays² | <<locked>> | 60% | 24,511 psi | 66% | 1237 fps | 100% |
| Hodgdon TrailBoss² | 5.3 gr | 60% | 9,703 psi | 26% | 912 fps | 100% |
| Lovex D037.1*² | <<locked>> | 60% | 28,645 psi | 77% | 1640 fps | 91.9% |
| Maxam CSB 1² | <<locked>> | 60% | 24,816 psi | 67% | 1375 fps | 100% |
| Maxam CSB 2² | <<locked>> | 60% | 27,340 psi | 74% | 1414 fps | 100% |
| Maxam CSB 3² | <<locked>> | 60% | 27,601 psi | 75% | 1398 fps | 100% |
| Maxam CSB 4² | <<locked>> | 60% | 29,095 psi | 79% | 1401 fps | 100% |
| ReloadSwiss RS 14² | 5.4 gr | 60% | 9,166 psi | 25% | 915 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 25,701 psi | 69% | 1460 fps | 100% |
| ReloadSwiss RS 24*² | <<locked>> | 60% | 24,091 psi | 65% | 1522 fps | 91.3% |
| Rottweil P 806² | <<locked>> | 60% | 21,408 psi | 58% | 1470 fps | 98.7% |
| Shooters World Major Pistol*² | <<locked>> | 60% | 28,645 psi | 77% | 1640 fps | 91.9% |
| SNPE Vectan A0² | <<locked>> | 60% | 24,555 psi | 66% | 1407 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 60% | 29,414 psi | 80% | 1467 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 60% | 21,625 psi | 58% | 1394 fps | 99.1% |
| SNPE Vectan BA9 1/2² | <<locked>> | 60% | 28,834 psi | 78% | 1457 fps | 100% |
| Somchem MS200² | <<locked>> | 60% | 27,441 psi | 74% | 1470 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 60% | 25,309 psi | 68% | 1496 fps | 100% |
| Vihtavuori 3N38*² | <<locked>> | 60% | 17,303 psi | 47% | 1325 fps | 86.1% |
| Vihtavuori N105*² | <<locked>> | 60% | 14,446 psi | 39% | 1280 fps | 86.5% |
| Vihtavuori N32C Tin Star² | 7.1 gr | 60% | 16,114 psi | 44% | 1079 fps | 100% |
| Vihtavuori N340² | <<locked>> | 60% | 27,035 psi | 73% | 1467 fps | 100% |
| Vihtavuori N350² | <<locked>> | 60% | 22,089 psi | 60% | 1421 fps | 99.7% |
| Winchester AutoComp ² | <<locked>> | 60% | 25,744 psi | 70% | 1411 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 41 powders for .357 Auto Mag. loaded with the .358 | 125gr | Rim Rock TC Cowboy. Vihtavuori N105 delivers the highest muzzle velocity at 1,739 fps; across all powders the maximum-charge window runs from 1,207 fps to 1,739 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 9 of the 41 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 .358 | 125gr | Rim Rock TC Cowboy they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate No. 7, 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.