Load Specifications
Load data in caliber 6 x 70 R with .243 | 80gr | Sierra VarmintKing bullet and 9 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are 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 ≥ 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: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 84% | 32,285 psi | 86% | 2641 fps | 99.1% |
| Accurate 4064 | <<locked>> | 86% | 32,358 psi | 86% | 2657 fps | 97.1% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 33,431 psi | 89% | 1857 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 33,431 psi | 89% | 2710 fps | 98.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 33,895 psi | 90% | 1906 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 33,301 psi | 88% | 2579 fps | 97.8% |
| Vihtavuori N135 | <<locked>> | 84% | 33,025 psi | 88% | 2651 fps | 99.2% |
| Vihtavuori N140 | <<locked>> | 82% | 32,068 psi | 85% | 2595 fps | 96.8% |
| Vihtavuori N540 | <<locked>> | 84% | 33,112 psi | 88% | 2631 fps | 96.6% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 28,166 psi | 75% | 2533 fps | 98% |
| Accurate 4064 | <<locked>> | 82% | 28,326 psi | 75% | 2549 fps | 95.4% |
| Hodgdon TrailBoss | 8.9 gr | 80% | 24,787 psi | 66% | 1663 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 31,430 psi | 83% | 2657 fps | 98% |
| ReloadSwiss RS 14 | 9.1 gr | 80% | 24,947 psi | 66% | 1706 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 27,485 psi | 73% | 2425 fps | 95.6% |
| Vihtavuori N135 | <<locked>> | 80% | 28,761 psi | 76% | 2543 fps | 98.1% |
| Vihtavuori N140 | <<locked>> | 80% | 30,211 psi | 80% | 2546 fps | 96.1% |
| Vihtavuori N540 | <<locked>> | 82% | 30,922 psi | 82% | 2575 fps | 95.8% |
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 9 powders for 6 x 70 R loaded with the .243 | 80gr | Sierra VarmintKing. IMR 3031 delivers the highest muzzle velocity at 2,710 fps; across all powders the maximum-charge window runs from 1,857 fps to 2,710 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 9 of the 9 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (260 MPa), the top charges use 85–90 %, leaving at least 10 % headroom. The 80.0 gr projectile in 0.243" calls for a 1:10.0 twist; slower twists will usually not stabilise this weight. 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. ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for 6 x 70 R with the .243 | 80gr | Sierra VarmintKing they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.