Load Specifications
Load data in caliber .303 Savage with .308 | 110gr | Sierra VarmintKing bullet and 5 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: 22"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 88% | 34,954 psi | 89% | 2635 fps | 98.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 29,486 psi | 75% | 1729 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 29,240 psi | 75% | 1772 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 82% | 33,634 psi | 86% | 2395 fps | 100% |
| Vihtavuori N120 | <<locked>> | 88% | 35,215 psi | 90% | 2608 fps | 99.4% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 22"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 80% | 27,180 psi | 69% | 2428 fps | 95.9% |
| Hodgdon TrailBoss | 9.6 gr | 80% | 21,553 psi | 55% | 1542 fps | 100% |
| ReloadSwiss RS 14 | 9.8 gr | 80% | 21,234 psi | 54% | 1581 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 32,068 psi | 82% | 2362 fps | 100% |
| Vihtavuori N120 | <<locked>> | 80% | 27,543 psi | 70% | 2411 fps | 97.4% |
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 5 powders for .303 Savage loaded with the .308 | 110gr | Sierra VarmintKing. ADI AR 2207 delivers the highest muzzle velocity at 2,635 fps; across all powders the maximum-charge window runs from 1,729 fps to 2,635 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 5 of the 5 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 75–90 %, leaving at least 10 % headroom. 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 .303 Savage with the .308 | 110gr | 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.