Load Specifications
Load data in caliber .357 Auto Mag. with .355 | 121gr | Frontier Bullets CMJ FP atch bullet and 37 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% | 33,127 psi | 90% | 1476 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 64% | 30,342 psi | 82% | 1493 fps | 100% |
| Accurate TCM*² | <<locked>> | 68% | 30,734 psi | 83% | 1690 fps | 88.5% |
| ADI AP 100 | <<locked>> | 80% | 32,648 psi | 88% | 1683 fps | 99.4% |
| ADI APS 350² | <<locked>> | 64% | 33,286 psi | 90% | 1368 fps | 100% |
| ADI APS 450² | <<locked>> | 64% | 32,692 psi | 88% | 1391 fps | 100% |
| ADI AS 30² | <<locked>> | 64% | 33,069 psi | 89% | 1437 fps | 100% |
| Alliant BE-86² | <<locked>> | 64% | 31,662 psi | 86% | 1496 fps | 100% |
| Alliant BLUE DOT* | <<locked>> | 80% | 32,227 psi | 87% | 1722 fps | 92.3% |
| Alliant Green Dot² | <<locked>> | 64% | 33,402 psi | 90% | 1493 fps | 100% |
| Alliant Herco² | <<locked>> | 76% | 31,241 psi | 84% | 1578 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 64% | 31,256 psi | 85% | 1699 fps | 98.7% |
| Alliant RED DOT² | <<locked>> | 64% | 32,213 psi | 87% | 1444 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 64% | 31,357 psi | 85% | 1588 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 64% | 32,793 psi | 89% | 1473 fps | 100% |
| Baschieri & Pellagri 102 Pistol | <<locked>> | 80% | 33,040 psi | 89% | 1483 fps | 100% |
| Hodgdon Clays² | <<locked>> | 72% | 32,547 psi | 88% | 1388 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 22,089 psi | 60% | 1237 fps | 100% |
| Maxam CSB 1² | <<locked>> | 68% | 31,908 psi | 86% | 1509 fps | 100% |
| Maxam CSB 2² | <<locked>> | 64% | 32,242 psi | 87% | 1506 fps | 100% |
| Maxam CSB 3² | <<locked>> | 64% | 31,923 psi | 86% | 1486 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 21,161 psi | 57% | 1257 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 64% | 29,950 psi | 81% | 1555 fps | 100% |
| ReloadSwiss RS 24² | <<locked>> | 68% | 32,967 psi | 89% | 1736 fps | 95.7% |
| Rottweil P 806² | <<locked>> | 68% | 30,995 psi | 84% | 1686 fps | 100% |
| SNPE Vectan A0² | <<locked>> | 68% | 31,589 psi | 85% | 1552 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 64% | 33,359 psi | 90% | 1545 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 72% | 31,502 psi | 85% | 1614 fps | 100% |
| SNPE Vectan BA9 1/2² | <<locked>> | 64% | 33,156 psi | 90% | 1545 fps | 100% |
| Somchem MS200² | <<locked>> | 64% | 32,126 psi | 87% | 1568 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 64% | 30,168 psi | 82% | 1608 fps | 100% |
| Vihtavuori 3N38² | <<locked>> | 76% | 30,153 psi | 82% | 1663 fps | 95.3% |
| Vihtavuori N105 | <<locked>> | 80% | 30,414 psi | 82% | 1716 fps | 98.3% |
| Vihtavuori N32C Tin Star | <<locked>> | 88% | 31,328 psi | 85% | 1368 fps | 100% |
| Vihtavuori N340² | <<locked>> | 64% | 31,894 psi | 86% | 1568 fps | 100% |
| Vihtavuori N350² | <<locked>> | 72% | 33,069 psi | 89% | 1654 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 64% | 30,211 psi | 82% | 1503 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% | 29,878 psi | 81% | 1424 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 60% | 27,253 psi | 74% | 1437 fps | 100% |
| Accurate TCM*² | <<locked>> | 64% | 26,760 psi | 72% | 1598 fps | 85.8% |
| ADI AP 100*² | <<locked>> | 60% | 19,276 psi | 52% | 1371 fps | 93.7% |
| ADI APS 350² | <<locked>> | 60% | 30,385 psi | 82% | 1322 fps | 100% |
| ADI APS 450² | <<locked>> | 60% | 29,457 psi | 80% | 1342 fps | 100% |
| ADI AS 30² | <<locked>> | 60% | 29,718 psi | 80% | 1385 fps | 100% |
| Alliant BE-86² | <<locked>> | 60% | 28,456 psi | 77% | 1440 fps | 100% |
| Alliant BLUE DOT*² | <<locked>> | 68% | 23,105 psi | 62% | 1506 fps | 86.3% |
| Alliant Green Dot² | <<locked>> | 60% | 30,168 psi | 82% | 1444 fps | 100% |
| Alliant Herco² | <<locked>> | 60% | 21,190 psi | 57% | 1371 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 60% | 27,818 psi | 75% | 1624 fps | 97.6% |
| Alliant RED DOT² | <<locked>> | 60% | 28,906 psi | 78% | 1388 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 60% | 28,036 psi | 76% | 1526 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 60% | 29,573 psi | 80% | 1421 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 20,204 psi | 55% | 1253 fps | 100% |
| Hodgdon Clays² | <<locked>> | 60% | 24,976 psi | 68% | 1260 fps | 100% |
| Hodgdon TrailBoss² | 5.3 gr | 60% | 11,023 psi | 30% | 945 fps | 100% |
| Maxam CSB 1² | <<locked>> | 60% | 25,715 psi | 70% | 1404 fps | 100% |
| Maxam CSB 2² | <<locked>> | 60% | 29,196 psi | 79% | 1457 fps | 100% |
| Maxam CSB 3² | <<locked>> | 60% | 28,834 psi | 78% | 1434 fps | 100% |
| ReloadSwiss RS 14² | 5.4 gr | 60% | 10,617 psi | 29% | 955 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 26,672 psi | 72% | 1496 fps | 100% |
| ReloadSwiss RS 24*² | <<locked>> | 60% | 25,512 psi | 69% | 1568 fps | 91.8% |
| Rottweil P 806² | <<locked>> | 60% | 23,844 psi | 64% | 1535 fps | 99.3% |
| SNPE Vectan A0² | <<locked>> | 60% | 25,715 psi | 70% | 1444 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 60% | 29,950 psi | 81% | 1493 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 60% | 22,626 psi | 61% | 1430 fps | 99.2% |
| SNPE Vectan BA9 1/2² | <<locked>> | 60% | 30,124 psi | 81% | 1496 fps | 100% |
| Somchem MS200² | <<locked>> | 60% | 28,732 psi | 78% | 1509 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 60% | 26,774 psi | 72% | 1542 fps | 100% |
| Vihtavuori 3N38*² | <<locked>> | 60% | 18,985 psi | 51% | 1385 fps | 87.5% |
| Vihtavuori N105*² | <<locked>> | 60% | 16,244 psi | 44% | 1348 fps | 88.6% |
| Vihtavuori N32C Tin Star² | 7.2 gr | 60% | 17,825 psi | 48% | 1119 fps | 100% |
| Vihtavuori N340² | <<locked>> | 60% | 28,456 psi | 77% | 1509 fps | 100% |
| Vihtavuori N350² | <<locked>> | 60% | 23,511 psi | 64% | 1467 fps | 99.9% |
| Winchester AutoComp ² | <<locked>> | 60% | 27,224 psi | 74% | 1450 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 37 powders for .357 Auto Mag. loaded with the .355 | 121gr | Frontier Bullets CMJ FP atch. ReloadSwiss RS 24 delivers the highest muzzle velocity at 1,736 fps; across all powders the maximum-charge window runs from 1,237 fps to 1,736 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 7 of the 37 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (255 MPa), the top charges use 57–90 %, 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 | 121gr | Frontier Bullets CMJ FP atch 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.