Load Specifications
Load data in caliber .350 Mag. Rigby with .358 | 200gr | Sierra Pro-Hunter bullet and 28 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Somchem S365, Hodgdon Hybrid 100V and Vihtavuori N150.
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 ≥ 80% and propellant combustion ≥ 95%. 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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 82% | 38,493 psi | 86% | 2644 fps | 100% |
| Accurate 4064 | <<locked>> | 84% | 38,827 psi | 86% | 2680 fps | 99.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 40,234 psi | 89% | 2713 fps | 97.6% |
| Alliant Reloder-17 | <<locked>> | 90% | 39,900 psi | 89% | 2789 fps | 97% |
| Bofors RP3 | <<locked>> | 86% | 39,871 psi | 89% | 2717 fps | 97.6% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 39,001 psi | 87% | 2703 fps | 96.7% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 38,696 psi | 86% | 2717 fps | 97.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,824 psi | 77% | 1804 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 40,379 psi | 90% | 2674 fps | 96.2% |
| IMR 4895 | <<locked>> | 82% | 39,044 psi | 87% | 2700 fps | 96.4% |
| Lovex S062 | <<locked>> | 84% | 40,161 psi | 89% | 2680 fps | 98% |
| Norma 203B | <<locked>> | 84% | 40,016 psi | 89% | 2710 fps | 96.6% |
| Ramshot Big Game | <<locked>> | 84% | 39,726 psi | 88% | 2726 fps | 96.3% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,114 psi | 78% | 1844 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 39,842 psi | 89% | 2805 fps | 99.1% |
| Rottweil R 902 | <<locked>> | 82% | 39,610 psi | 88% | 2648 fps | 97.8% |
| Rottweil R 903 | <<locked>> | 88% | 39,929 psi | 89% | 2710 fps | 97.3% |
| Shooters World Precision | <<locked>> | 84% | 40,161 psi | 89% | 2680 fps | 98% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 38,624 psi | 86% | 2707 fps | 96% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 40,567 psi | 90% | 2621 fps | 99.9% |
| Somchem S355 | <<locked>> | 86% | 38,290 psi | 85% | 2661 fps | 96.6% |
| Somchem S365 | <<locked>> | 98% | 40,553 psi | 90% | 2812 fps | 98.6% |
| Vihtavuori N135 | <<locked>> | 82% | 38,667 psi | 86% | 2641 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 39,581 psi | 88% | 2648 fps | 99.6% |
| Vihtavuori N150 | <<locked>> | 88% | 39,088 psi | 87% | 2654 fps | 98.2% |
| Vihtavuori N540 | <<locked>> | 84% | 40,683 psi | 90% | 2684 fps | 99.5% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 39,958 psi | 89% | 2684 fps | 97.1% |
| Winchester StaBALL Match | <<locked>> | 82% | 40,335 psi | 90% | 2710 fps | 97.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 36,013 psi | 80% | 2592 fps | 100% |
| Accurate 4064 | <<locked>> | 80% | 34,055 psi | 76% | 2572 fps | 98.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 33,272 psi | 74% | 2549 fps | 95.3% |
| Alliant Reloder-17 | <<locked>> | 86% | 34,940 psi | 78% | 2664 fps | 95% |
| Bofors RP3 | <<locked>> | 80% | 32,532 psi | 72% | 2546 fps | 95.2% |
| Hodgdon Hybrid 100V | 71.9 gr | 92% | 34,418 psi | 77% | 2595 fps | 95% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 36,158 psi | 80% | 2657 fps | 96.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,933 psi | 58% | 1614 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 38,000 psi | 85% | 2621 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 36,622 psi | 81% | 2641 fps | 95.6% |
| Lovex S062 | <<locked>> | 80% | 35,346 psi | 79% | 2572 fps | 96.6% |
| Norma 203B | <<locked>> | 80% | 35,172 psi | 78% | 2598 fps | 95% |
| Ramshot Big Game | <<locked>> | 82% | 37,028 psi | 82% | 2664 fps | 95.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,136 psi | 58% | 1650 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 30,647 psi | 68% | 2556 fps | 95.7% |
| Rottweil R 902 | <<locked>> | 80% | 37,289 psi | 83% | 2595 fps | 97.2% |
| Rottweil R 903 | <<locked>> | 84% | 34,998 psi | 78% | 2598 fps | 95.8% |
| Shooters World Precision | <<locked>> | 80% | 35,346 psi | 79% | 2572 fps | 96.6% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 36,172 psi | 80% | 2648 fps | 95.1% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 33,562 psi | 75% | 2474 fps | 99.1% |
| Somchem S355 | <<locked>> | 82% | 33,837 psi | 75% | 2556 fps | 95.1% |
| Somchem S365 | 72.3 gr | 90% | 31,415 psi | 70% | 2579 fps | 95.3% |
| Vihtavuori N135 | <<locked>> | 80% | 36,274 psi | 81% | 2592 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 37,115 psi | 83% | 2595 fps | 99.3% |
| Vihtavuori N150 | 63.9 gr | 80% | 30,037 psi | 67% | 2438 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 35,723 psi | 79% | 2579 fps | 98.7% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 35,114 psi | 78% | 2569 fps | 95.4% |
| Winchester StaBALL Match | <<locked>> | 80% | 37,710 psi | 84% | 2654 fps | 96.5% |
Recommended = one of the top powders for this cartridge and bullet combination.
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 54 powders for .350 Mag. Rigby loaded with the .358 | 200gr | Sierra Pro-Hunter. Somchem S365 delivers the highest muzzle velocity at 2,812 fps; across all powders the maximum-charge window runs from 1,804 fps to 2,812 fps. Alliant Reloder-23 gives the best case fill at 100 %, and 54 of the 54 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (310 MPa), the top charges use 76–90 %, leaving at least 10 % headroom. Alliant Reloder-23, Alliant Reloder-26, Hodgdon TrailBoss 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. Somchem S365, Hodgdon Hybrid 100V, Vihtavuori N150 rank at the top here: for .350 Mag. Rigby with the .358 | 200gr | Sierra Pro-Hunter they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Power Pro 2000-MR, Alliant Reloder-23, Alliant Reloder-26 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.