Load Specifications
Load data in caliber .357 Auto Mag. with .357 | 170gr | Speer SP MAG GD bullet and 32 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 4100* | <<locked>> | 80% | 33,402 psi | 90% | 1490 fps | 88.3% |
| Accurate No. 9*² | <<locked>> | 64% | 29,066 psi | 79% | 1401 fps | 91.7% |
| Accurate Solo 1250² | <<locked>> | 64% | 32,634 psi | 88% | 1247 fps | 100% |
| Accurate TCM*² | <<locked>> | 64% | 29,370 psi | 79% | 1401 fps | 93.1% |
| ADI AP 100² | <<locked>> | 76% | 31,966 psi | 86% | 1385 fps | 100% |
| Alliant 2400*² | <<locked>> | 76% | 33,069 psi | 89% | 1490 fps | 91.1% |
| Alliant BLUE DOT² | <<locked>> | 76% | 31,299 psi | 85% | 1434 fps | 96.3% |
| Alliant Herco² | <<locked>> | 76% | 33,257 psi | 90% | 1325 fps | 100% |
| Alliant RED DOT² | <<locked>> | 64% | 33,460 psi | 90% | 1194 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 76% | 31,488 psi | 85% | 1194 fps | 100% |
| Hodgdon Clays² | <<locked>> | 68% | 31,053 psi | 84% | 1112 fps | 100% |
| Hodgdon LilGun* | <<locked>> | 84% | 29,457 psi | 80% | 1503 fps | 89.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 22,887 psi | 62% | 1027 fps | 100% |
| Lovex D037.2*² | <<locked>> | 64% | 29,501 psi | 80% | 1411 fps | 92% |
| Maxam CSB 1² | <<locked>> | 68% | 33,431 psi | 90% | 1253 fps | 100% |
| Maxam CSB 3² | <<locked>> | 64% | 33,286 psi | 90% | 1227 fps | 100% |
| Ramshot Enforcer*² | <<locked>> | 76% | 32,474 psi | 88% | 1490 fps | 92% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 21,393 psi | 58% | 1037 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 64% | 32,213 psi | 87% | 1299 fps | 100% |
| ReloadSwiss RS 24² | <<locked>> | 64% | 31,415 psi | 85% | 1424 fps | 98.5% |
| Rottweil P 806² | <<locked>> | 68% | 33,417 psi | 90% | 1437 fps | 100% |
| Shooters World Heavy Pistol*² | <<locked>> | 64% | 29,501 psi | 80% | 1411 fps | 92% |
| SNPE Vectan A0² | <<locked>> | 64% | 30,487 psi | 82% | 1253 fps | 100% |
| SNPE Vectan BA6 1/2*ᴾ | <<locked>> | 100% | 29,515 psi | 80% | 1434 fps | 92.8% |
| SNPE Vectan BA7 1/2² | <<locked>> | 68% | 30,618 psi | 83% | 1319 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 64% | 32,489 psi | 88% | 1358 fps | 100% |
| Vihtavuori 3N38² | <<locked>> | 76% | 32,822 psi | 89% | 1437 fps | 99.3% |
| Vihtavuori N105² | <<locked>> | 76% | 29,979 psi | 81% | 1424 fps | 100% |
| Vihtavuori N110* | <<locked>> | 96% | 33,185 psi | 90% | 1516 fps | 91.9% |
| Vihtavuori N32C Tin Star | <<locked>> | 88% | 32,547 psi | 88% | 1135 fps | 100% |
| Vihtavuori N350² | <<locked>> | 68% | 32,010 psi | 87% | 1345 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 64% | 31,618 psi | 85% | 1250 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 4100*² | <<locked>> | 76% | 29,443 psi | 80% | 1421 fps | 85.9% |
| Accurate No. 9*² | <<locked>> | 60% | 25,048 psi | 68% | 1322 fps | 89.1% |
| Accurate Solo 1250² | <<locked>> | 60% | 28,935 psi | 78% | 1198 fps | 100% |
| Accurate TCM*² | <<locked>> | 60% | 25,237 psi | 68% | 1322 fps | 90.6% |
| ADI AP 100² | <<locked>> | 60% | 20,247 psi | 55% | 1168 fps | 98.2% |
| Alliant 2400*² | <<locked>> | 68% | 25,396 psi | 69% | 1345 fps | 86.3% |
| Alliant BLUE DOT*² | <<locked>> | 60% | 19,131 psi | 52% | 1178 fps | 88.5% |
| Alliant Herco² | <<locked>> | 60% | 21,814 psi | 59% | 1145 fps | 100% |
| Alliant RED DOT² | <<locked>> | 60% | 30,139 psi | 81% | 1148 fps | 100% |
| Baschieri & Pellagri 102 Pistol² | <<locked>> | 60% | 20,784 psi | 56% | 1040 fps | 100% |
| Hodgdon Clays² | <<locked>> | 60% | 25,846 psi | 70% | 1040 fps | 100% |
| Hodgdon LilGun* | <<locked>> | 80% | 25,730 psi | 70% | 1427 fps | 87.1% |
| Hodgdon TrailBoss² | 4.7 gr | 60% | 10,515 psi | 28% | 771 fps | 100% |
| Lovex D037.2*² | <<locked>> | 60% | 25,411 psi | 69% | 1332 fps | 89.4% |
| Maxam CSB 1² | <<locked>> | 60% | 27,064 psi | 73% | 1168 fps | 100% |
| Maxam CSB 3² | <<locked>> | 60% | 30,182 psi | 82% | 1188 fps | 100% |
| Ramshot Enforcer*² | <<locked>> | 68% | 24,555 psi | 66% | 1342 fps | 87% |
| ReloadSwiss RS 14² | 4.8 gr | 60% | 10,037 psi | 27% | 781 fps | 100% |
| ReloadSwiss RS 20² | <<locked>> | 60% | 28,747 psi | 78% | 1253 fps | 100% |
| ReloadSwiss RS 24² | <<locked>> | 60% | 27,630 psi | 75% | 1358 fps | 97.3% |
| Rottweil P 806² | <<locked>> | 60% | 25,150 psi | 68% | 1309 fps | 100% |
| Shooters World Heavy Pistol*² | <<locked>> | 60% | 25,411 psi | 69% | 1332 fps | 89.4% |
| SNPE Vectan A0² | <<locked>> | 60% | 27,267 psi | 74% | 1207 fps | 100% |
| SNPE Vectan BA6 1/2* | <<locked>> | 88% | 21,350 psi | 58% | 1266 fps | 86.7% |
| SNPE Vectan BA7 1/2² | <<locked>> | 60% | 24,105 psi | 65% | 1214 fps | 100% |
| Vihtavuori 3N37² | <<locked>> | 60% | 28,776 psi | 78% | 1302 fps | 100% |
| Vihtavuori 3N38*² | <<locked>> | 60% | 19,841 psi | 54% | 1188 fps | 93.7% |
| Vihtavuori N105² | <<locked>> | 60% | 17,448 psi | 47% | 1171 fps | 95.5% |
| Vihtavuori N110* | <<locked>> | 88% | 25,933 psi | 70% | 1385 fps | 87.4% |
| Vihtavuori N32C Tin Star² | 6.4 gr | 60% | 17,825 psi | 48% | 919 fps | 100% |
| Vihtavuori N350² | <<locked>> | 60% | 25,208 psi | 68% | 1243 fps | 100% |
| Winchester AutoComp ² | <<locked>> | 60% | 28,500 psi | 77% | 1207 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 32 powders for .357 Auto Mag. loaded with the .357 | 170gr | Speer SP MAG GD. Vihtavuori N110 delivers the highest muzzle velocity at 1,516 fps; across all powders the maximum-charge window runs from 1,027 fps to 1,516 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 7 of the 32 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (255 MPa), the top charges use 58–90 %, leaving at least 10 % headroom. Hodgdon TrailBoss, ReloadSwiss RS 14, SNPE Vectan BA6 1/2 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 | 170gr | Speer SP MAG GD they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 4100, Accurate No. 9, Accurate TCM burn incompletely and react more sensitively to barrel length and temperature. Baschieri & Pellagri 102 Pistol, Hodgdon Clays, Hodgdon TrailBoss 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.