Load Specifications
Load data in caliber .357 Auto Mag. with .356 | 125gr | X-TREME RN 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% | 32,953 psi | 89% | 1437 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 64% | 30,284 psi | 82% | 1457 fps | 100% |
| Accurate TCM*² | <<locked>> | 68% | 30,327 psi | 82% | 1647 fps | 88.5% |
| ADI AP 100 | <<locked>> | 80% | 31,981 psi | 86% | 1634 fps | 99.4% |
| ADI APS 350² | <<locked>> | 64% | 33,460 psi | 90% | 1335 fps | 100% |
| ADI APS 450² | <<locked>> | 64% | 32,460 psi | 88% | 1355 fps | 100% |
| ADI AS 30² | <<locked>> | 64% | 32,750 psi | 89% | 1398 fps | 100% |
| Alliant BE-86² | <<locked>> | 64% | 31,415 psi | 85% | 1457 fps | 100% |
| Alliant BLUE DOT* | <<locked>> | 80% | 31,604 psi | 85% | 1673 fps | 92.3% |
| Alliant Green Dot² | <<locked>> | 64% | 32,663 psi | 88% | 1447 fps | 100% |
| Alliant Herco² | <<locked>> | 76% | 30,763 psi | 83% | 1532 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 64% | 30,835 psi | 83% | 1654 fps | 98.7% |
| Alliant RED DOT² | <<locked>> | 64% | 31,850 psi | 86% | 1404 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 64% | 30,937 psi | 84% | 1542 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 64% | 32,793 psi | 89% | 1437 fps | 100% |
| Baschieri & Pellagri 102 Pistol | <<locked>> | 80% | 32,953 psi | 89% | 1447 fps | 100% |
| Hodgdon Clays² | <<locked>> | 72% | 32,343 psi | 87% | 1352 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 21,886 psi | 59% | 1204 fps | 100% |
| Maxam CSB 1² | <<locked>> | 68% | 31,488 psi | 85% | 1467 fps | 100% |
| Maxam CSB 2² | <<locked>> | 64% | 32,198 psi | 87% | 1470 fps | 100% |
| Maxam CSB 3² | <<locked>> | 64% | 31,299 psi | 85% | 1440 fps | 100% |
| Maxam CSB 4² | <<locked>> | 64% | 33,460 psi | 90% | 1450 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 20,987 psi | 57% | 1224 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 68% | 33,301 psi | 90% | 1572 fps | 100% |
| ReloadSwiss RS 24² | <<locked>> | 68% | 32,547 psi | 88% | 1690 fps | 95.7% |
| Rottweil P 806² | <<locked>> | 68% | 30,429 psi | 82% | 1644 fps | 100% |
| SNPE Vectan A0² | <<locked>> | 68% | 31,328 psi | 85% | 1509 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 64% | 33,156 psi | 90% | 1506 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 72% | 31,227 psi | 84% | 1575 fps | 100% |
| SNPE Vectan BA9 1/2² | <<locked>> | 64% | 33,330 psi | 90% | 1509 fps | 100% |
| Somchem MS200² | <<locked>> | 64% | 31,792 psi | 86% | 1526 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 64% | 30,211 psi | 82% | 1572 fps | 100% |
| Vihtavuori 3N38 | <<locked>> | 80% | 33,199 psi | 90% | 1686 fps | 96.7% |
| Vihtavuori N105 | <<locked>> | 80% | 29,936 psi | 81% | 1677 fps | 98.4% |
| Vihtavuori N32C Tin Star | <<locked>> | 88% | 31,459 psi | 85% | 1339 fps | 100% |
| Vihtavuori N340² | <<locked>> | 64% | 31,575 psi | 85% | 1526 fps | 100% |
| Vihtavuori N350² | <<locked>> | 72% | 32,634 psi | 88% | 1611 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 68% | 33,344 psi | 90% | 1519 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% | 29,573 psi | 80% | 1385 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 60% | 27,137 psi | 73% | 1401 fps | 100% |
| Accurate TCM*² | <<locked>> | 64% | 26,600 psi | 72% | 1565 fps | 86% |
| ADI AP 100*² | <<locked>> | 60% | 19,043 psi | 51% | 1335 fps | 93.8% |
| ADI APS 350² | <<locked>> | 60% | 30,429 psi | 82% | 1289 fps | 100% |
| ADI APS 450² | <<locked>> | 60% | 29,109 psi | 79% | 1302 fps | 100% |
| ADI AS 30² | <<locked>> | 60% | 29,849 psi | 81% | 1352 fps | 100% |
| Alliant BE-86² | <<locked>> | 60% | 28,094 psi | 76% | 1401 fps | 100% |
| Alliant BLUE DOT*² | <<locked>> | 68% | 22,916 psi | 62% | 1473 fps | 86.5% |
| Alliant Green Dot² | <<locked>> | 60% | 29,892 psi | 81% | 1401 fps | 100% |
| Alliant Herco² | <<locked>> | 60% | 20,740 psi | 56% | 1329 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 60% | 27,267 psi | 74% | 1578 fps | 97.6% |
| Alliant RED DOT² | <<locked>> | 60% | 28,964 psi | 78% | 1355 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 60% | 27,992 psi | 76% | 1490 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 60% | 29,472 psi | 80% | 1385 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 20,059 psi | 54% | 1224 fps | 100% |
| Hodgdon Clays² | <<locked>> | 60% | 24,990 psi | 68% | 1227 fps | 100% |
| Hodgdon TrailBoss² | 5.1 gr | 60% | 11,037 psi | 30% | 922 fps | 100% |
| Maxam CSB 1² | <<locked>> | 60% | 25,541 psi | 69% | 1368 fps | 100% |
| Maxam CSB 2² | <<locked>> | 60% | 29,037 psi | 79% | 1417 fps | 100% |
| Maxam CSB 3² | <<locked>> | 60% | 28,616 psi | 77% | 1394 fps | 100% |
| Maxam CSB 4² | <<locked>> | 60% | 30,052 psi | 81% | 1398 fps | 100% |
| ReloadSwiss RS 14² | 5.2 gr | 60% | 10,660 psi | 29% | 932 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 26,687 psi | 72% | 1460 fps | 100% |
| ReloadSwiss RS 24*² | <<locked>> | 60% | 25,280 psi | 68% | 1532 fps | 91.9% |
| Rottweil P 806² | <<locked>> | 60% | 23,482 psi | 63% | 1496 fps | 99.4% |
| SNPE Vectan A0² | <<locked>> | 60% | 25,266 psi | 68% | 1401 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 60% | 29,631 psi | 80% | 1450 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 60% | 22,423 psi | 61% | 1394 fps | 99.3% |
| SNPE Vectan BA9 1/2² | <<locked>> | 60% | 29,617 psi | 80% | 1450 fps | 100% |
| Somchem MS200² | <<locked>> | 60% | 28,224 psi | 76% | 1467 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 60% | 26,643 psi | 72% | 1506 fps | 100% |
| Vihtavuori 3N38*² | <<locked>> | 60% | 18,565 psi | 50% | 1342 fps | 87.4% |
| Vihtavuori N105*² | <<locked>> | 60% | 16,128 psi | 44% | 1319 fps | 88.9% |
| Vihtavuori N32C Tin Star² | 6.9 gr | 60% | 17,753 psi | 48% | 1089 fps | 100% |
| Vihtavuori N340² | <<locked>> | 60% | 28,036 psi | 76% | 1467 fps | 100% |
| Vihtavuori N350² | <<locked>> | 60% | 23,235 psi | 63% | 1427 fps | 99.9% |
| Winchester AutoComp ² | <<locked>> | 60% | 26,963 psi | 73% | 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 38 powders for .357 Auto Mag. loaded with the .356 | 125gr | X-TREME RN. ReloadSwiss RS 24 delivers the highest muzzle velocity at 1,690 fps; across all powders the maximum-charge window runs from 1,204 fps to 1,690 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 8 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 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 .356 | 125gr | X-TREME RN 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.