Load Specifications
Load data in caliber 6 x 70 R with .243 | 100gr | Speer Boat-Tail bullet and 8 powders. The key underlying parameters are shown in the table above.
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 |
|---|---|---|---|---|---|---|
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 33,852 psi | 90% | 2428 fps | 96.6% |
| Bofors RP3 | <<locked>> | 82% | 33,098 psi | 88% | 2421 fps | 96.5% |
| Hodgdon TrailBoss | <<locked>> | 98% | 33,605 psi | 89% | 1654 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 98% | 33,866 psi | 90% | 1693 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 33,417 psi | 89% | 2497 fps | 98.1% |
| Rottweil R 903 | <<locked>> | 84% | 33,344 psi | 88% | 2421 fps | 96.2% |
| Somchem S365 | <<locked>> | 94% | 33,779 psi | 90% | 2503 fps | 97.4% |
| Vihtavuori N150 | <<locked>> | 84% | 32,793 psi | 87% | 2372 fps | 97.2% |
Start Load - Barrel Length: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 31,488 psi | 84% | 2372 fps | 95.7% |
| Bofors RP3 | <<locked>> | 80% | 30,806 psi | 82% | 2369 fps | 95.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,512 psi | 68% | 1493 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,831 psi | 69% | 1529 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 29,211 psi | 77% | 2379 fps | 96.2% |
| Rottweil R 903 | <<locked>> | 82% | 31,009 psi | 82% | 2365 fps | 95.3% |
| Somchem S365 | <<locked>> | 90% | 29,747 psi | 79% | 2398 fps | 95.7% |
| Vihtavuori N150 | <<locked>> | 80% | 28,732 psi | 76% | 2274 fps | 95.6% |
This overview compares 8 powders for 6 x 70 R loaded with the .243 | 100gr | Speer Boat-Tail. Somchem S365 delivers the highest muzzle velocity at 2,503 fps; across all powders the maximum-charge window runs from 1,654 fps to 2,503 fps. Hodgdon TrailBoss gives the best case fill at 98 %, and 8 of the 8 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (260 MPa), the top charges use 87–90 %, leaving at least 10 % headroom. The 100.0 gr projectile in 0.243" calls for a 1:10.0 twist; slower twists will usually not stabilise this weight. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.