Load Specifications
Load data in caliber .357 Auto Mag. with .355 | 124gr | Speer HPSB GD bullet and 46 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. 2² | <<locked>> | 64% | 32,677 psi | 88% | 1565 fps | 100% |
| Accurate No. 7*² | <<locked>> | 64% | 32,401 psi | 88% | 1719 fps | 93.6% |
| Accurate No. 9*² | <<locked>> | 72% | 32,372 psi | 88% | 1709 fps | 88.2% |
| Accurate Solo 1000² | <<locked>> | 64% | 32,097 psi | 87% | 1440 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 68% | 32,285 psi | 87% | 1506 fps | 100% |
| Accurate TCM*² | <<locked>> | 72% | 32,576 psi | 88% | 1709 fps | 89.7% |
| ADI AP 100 | <<locked>> | 80% | 30,850 psi | 83% | 1634 fps | 99.1% |
| ADI APS 350² | <<locked>> | 64% | 32,358 psi | 87% | 1332 fps | 100% |
| ADI APS 450² | <<locked>> | 64% | 31,299 psi | 85% | 1352 fps | 100% |
| ADI AS 30² | <<locked>> | 64% | 31,633 psi | 86% | 1401 fps | 100% |
| Alliant BE-86² | <<locked>> | 68% | 33,417 psi | 90% | 1506 fps | 100% |
| Alliant BLUE DOT* | <<locked>> | 84% | 33,228 psi | 90% | 1726 fps | 93% |
| Alliant Green Dot² | <<locked>> | 64% | 31,386 psi | 85% | 1447 fps | 100% |
| Alliant Herco | <<locked>> | 80% | 32,184 psi | 87% | 1581 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 68% | 32,938 psi | 89% | 1716 fps | 99.1% |
| Alliant RED DOT² | <<locked>> | 64% | 30,676 psi | 83% | 1404 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 68% | 32,895 psi | 89% | 1598 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 64% | 31,531 psi | 85% | 1437 fps | 100% |
| Baschieri & Pellagri 102 Pistol | <<locked>> | 80% | 31,328 psi | 85% | 1444 fps | 100% |
| Hodgdon Clays² | <<locked>> | 72% | 31,705 psi | 86% | 1355 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 20,392 psi | 55% | 1198 fps | 100% |
| Lovex D037.1*² | <<locked>> | 64% | 32,401 psi | 88% | 1719 fps | 93.6% |
| Lovex D037.2*² | <<locked>> | 72% | 33,272 psi | 90% | 1729 fps | 88.8% |
| Maxam CSB 1² | <<locked>> | 72% | 33,359 psi | 90% | 1519 fps | 100% |
| Maxam CSB 2² | <<locked>> | 64% | 30,342 psi | 82% | 1467 fps | 100% |
| Maxam CSB 3² | <<locked>> | 64% | 30,110 psi | 81% | 1440 fps | 100% |
| Maxam CSB 4² | <<locked>> | 64% | 31,778 psi | 86% | 1444 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 19,189 psi | 52% | 1214 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 68% | 31,647 psi | 86% | 1565 fps | 100% |
| ReloadSwiss RS 24*² | <<locked>> | 68% | 30,603 psi | 83% | 1670 fps | 94.8% |
| Rottweil P 806² | <<locked>> | 72% | 31,734 psi | 86% | 1690 fps | 100% |
| Shooters World Heavy Pistol*² | <<locked>> | 72% | 33,272 psi | 90% | 1729 fps | 88.8% |
| Shooters World Major Pistol*² | <<locked>> | 64% | 32,401 psi | 88% | 1719 fps | 93.6% |
| SNPE Vectan A0² | <<locked>> | 68% | 30,095 psi | 81% | 1509 fps | 100% |
| SNPE Vectan A1² | <<locked>> | 64% | 32,692 psi | 88% | 1493 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 64% | 31,966 psi | 86% | 1506 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 76% | 33,301 psi | 90% | 1627 fps | 100% |
| SNPE Vectan BA9 1/2² | <<locked>> | 64% | 31,879 psi | 86% | 1509 fps | 100% |
| Somchem MS200² | <<locked>> | 64% | 30,371 psi | 82% | 1522 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 68% | 32,169 psi | 87% | 1627 fps | 100% |
| Vihtavuori 3N38 | <<locked>> | 80% | 31,517 psi | 85% | 1677 fps | 96% |
| Vihtavuori N105 | <<locked>> | 84% | 31,314 psi | 85% | 1722 fps | 98.7% |
| Vihtavuori N32C Tin Star | <<locked>> | 92% | 31,836 psi | 86% | 1365 fps | 100% |
| Vihtavuori N340² | <<locked>> | 64% | 30,052 psi | 81% | 1522 fps | 100% |
| Vihtavuori N350² | <<locked>> | 72% | 31,401 psi | 85% | 1611 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 68% | 31,662 psi | 86% | 1512 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. 2² | <<locked>> | 60% | 29,095 psi | 79% | 1506 fps | 100% |
| Accurate No. 7*² | <<locked>> | 60% | 27,775 psi | 75% | 1624 fps | 91.1% |
| Accurate No. 9*² | <<locked>> | 68% | 27,963 psi | 76% | 1617 fps | 85.4% |
| Accurate Solo 1000² | <<locked>> | 60% | 28,689 psi | 78% | 1388 fps | 100% |
| Accurate Solo 1250² | <<locked>> | 60% | 25,831 psi | 70% | 1401 fps | 100% |
| Accurate TCM*² | <<locked>> | 68% | 28,500 psi | 77% | 1624 fps | 87.2% |
| ADI AP 100*² | <<locked>> | 60% | 17,550 psi | 47% | 1309 fps | 92.2% |
| ADI APS 350² | <<locked>> | 60% | 29,950 psi | 81% | 1296 fps | 100% |
| ADI APS 450² | <<locked>> | 60% | 28,514 psi | 77% | 1306 fps | 100% |
| ADI AS 30² | <<locked>> | 60% | 28,210 psi | 76% | 1345 fps | 100% |
| Alliant BE-86² | <<locked>> | 60% | 26,614 psi | 72% | 1398 fps | 100% |
| Alliant BLUE DOT*² | <<locked>> | 72% | 23,569 psi | 64% | 1509 fps | 86.8% |
| Alliant Green Dot² | <<locked>> | 60% | 28,645 psi | 77% | 1404 fps | 100% |
| Alliant Herco² | <<locked>> | 60% | 19,102 psi | 52% | 1316 fps | 100% |
| Alliant POWER PISTOL² | <<locked>> | 60% | 25,614 psi | 69% | 1562 fps | 96.7% |
| Alliant RED DOT² | <<locked>> | 60% | 27,789 psi | 75% | 1355 fps | 100% |
| Alliant UNIQUE² | <<locked>> | 60% | 26,324 psi | 71% | 1480 fps | 100% |
| Baschieri & Pellagri 100² | <<locked>> | 60% | 28,224 psi | 76% | 1388 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 18,536 psi | 50% | 1214 fps | 100% |
| Hodgdon Clays² | <<locked>> | 60% | 24,323 psi | 66% | 1234 fps | 100% |
| Hodgdon TrailBoss² | 5.1 gr | 60% | 9,398 psi | 25% | 902 fps | 100% |
| Lovex D037.1*² | <<locked>> | 60% | 27,775 psi | 75% | 1624 fps | 91.1% |
| Lovex D037.2*² | <<locked>> | 68% | 28,689 psi | 78% | 1634 fps | 85.9% |
| Maxam CSB 1² | <<locked>> | 60% | 24,207 psi | 65% | 1362 fps | 100% |
| Maxam CSB 2² | <<locked>> | 60% | 26,629 psi | 72% | 1404 fps | 100% |
| Maxam CSB 3² | <<locked>> | 60% | 26,919 psi | 73% | 1388 fps | 100% |
| Maxam CSB 4² | <<locked>> | 60% | 28,935 psi | 78% | 1398 fps | 100% |
| ReloadSwiss RS 14² | 5.2 gr | 60% | 8,891 psi | 24% | 906 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 25,106 psi | 68% | 1453 fps | 100% |
| ReloadSwiss RS 24*² | <<locked>> | 60% | 23,467 psi | 63% | 1506 fps | 90.5% |
| Rottweil P 806² | <<locked>> | 60% | 20,813 psi | 56% | 1457 fps | 98.3% |
| Shooters World Heavy Pistol*² | <<locked>> | 68% | 28,689 psi | 78% | 1634 fps | 85.9% |
| Shooters World Major Pistol*² | <<locked>> | 60% | 27,775 psi | 75% | 1624 fps | 91.1% |
| SNPE Vectan A0² | <<locked>> | 60% | 24,033 psi | 65% | 1398 fps | 100% |
| SNPE Vectan A1² | <<locked>> | 60% | 29,225 psi | 79% | 1437 fps | 100% |
| SNPE Vectan BA 9² | <<locked>> | 60% | 28,471 psi | 77% | 1450 fps | 100% |
| SNPE Vectan BA7 1/2² | <<locked>> | 60% | 20,943 psi | 57% | 1378 fps | 98.7% |
| SNPE Vectan BA9 1/2² | <<locked>> | 60% | 28,282 psi | 76% | 1450 fps | 100% |
| Somchem MS200² | <<locked>> | 60% | 26,876 psi | 73% | 1463 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 60% | 24,918 psi | 67% | 1490 fps | 99.9% |
| Vihtavuori 3N38*² | <<locked>> | 64% | 19,072 psi | 52% | 1381 fps | 87.7% |
| Vihtavuori N105*² | <<locked>> | 60% | 14,069 psi | 38% | 1270 fps | 85.5% |
| Vihtavuori N32C Tin Star² | 6.9 gr | 60% | 15,867 psi | 43% | 1076 fps | 100% |
| Vihtavuori N340² | <<locked>> | 60% | 26,484 psi | 72% | 1460 fps | 100% |
| Vihtavuori N350² | <<locked>> | 60% | 21,611 psi | 58% | 1411 fps | 99.6% |
| Winchester AutoComp ² | <<locked>> | 60% | 25,324 psi | 68% | 1404 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 46 powders for .357 Auto Mag. loaded with the .355 | 124gr | Speer HPSB GD. Lovex D037.2 delivers the highest muzzle velocity at 1,729 fps; across all powders the maximum-charge window runs from 1,198 fps to 1,729 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 9 of the 46 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (255 MPa), the top charges use 52–90 %, 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 | 124gr | Speer HPSB GD they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate No. 7, Accurate No. 9, Accurate TCM 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.