Load Specifications
Load data in caliber .455 MK II with .452 | 190gr | LEE Mold 452-190-SWC bullet and 8 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.
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: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate Solo 1250*² | <<locked>> | 64% | 11,081 psi | 85% | 768 fps | 89.1% |
| Alliant BE-86*² | <<locked>> | 64% | 11,284 psi | 86% | 784 fps | 92.7% |
| Baschieri & Pellagri 102 Pistol | <<locked>> | 80% | 11,284 psi | 86% | 791 fps | 96.8% |
| Hodgdon TrailBoss*ᴾ | <<locked>> | 100% | 7,426 psi | 57% | 653 fps | 94.6% |
| Maxam CSB 1*² | <<locked>> | 64% | 10,602 psi | 81% | 751 fps | 88.4% |
| Maxam CSB 2*² | <<locked>> | 68% | 10,472 psi | 80% | 804 fps | 94.7% |
| Vihtavuori N32C Tin Star | <<locked>> | 88% | 11,023 psi | 84% | 764 fps | 100% |
| Vihtavuori N330*² | <<locked>> | 64% | 11,734 psi | 90% | 820 fps | 92.1% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 4"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate Solo 1250*² | <<locked>> | 60% | 9,703 psi | 74% | 728 fps | 86.5% |
| Alliant BE-86*² | <<locked>> | 60% | 9,631 psi | 74% | 738 fps | 90% |
| Baschieri & Pellagri 102 Pistol*² | <<locked>> | 60% | 6,411 psi | 49% | 627 fps | 87.1% |
| Hodgdon TrailBoss*² | <<locked>> | 76% | 4,540 psi | 35% | 528 fps | 85.3% |
| Maxam CSB 1*² | <<locked>> | 60% | 9,326 psi | 71% | 712 fps | 85.9% |
| Maxam CSB 2*² | <<locked>> | 60% | 7,992 psi | 61% | 722 fps | 89.9% |
| Vihtavuori N32C Tin Star*² | 3.4 gr | 60% | 5,091 psi | 39% | 568 fps | 93.5% |
| Vihtavuori N330*² | <<locked>> | 60% | 10,356 psi | 79% | 778 fps | 89.7% |
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 2 powders for .455 MK II loaded with the .452 | 190gr | LEE Mold 452-190-SWC. Vihtavuori N32C Tin Star delivers the highest muzzle velocity at 764 fps; across all powders the maximum-charge window runs from 653 fps to 764 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 2 of the 2 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (90 MPa), the top charges use 57–84 %, leaving at least 16 % headroom. 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. Vihtavuori N32C Tin Star rank at the top here: for .455 MK II with the .452 | 190gr | LEE Mold 452-190-SWC they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon TrailBoss burn incompletely and react more sensitively to barrel length and temperature. Hodgdon TrailBoss, 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.