Load Specifications
Load data in caliber .303 Savage with .308 | 122gr | Sax KJG-SX bullet and 8 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2207, Vihtavuori N120 and ReloadSwiss RS 14.
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>> | 90% | 34,360 psi | 88% | 2425 fps | 98.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 29,167 psi | 74% | 1565 fps | 100% |
| IMR 4227 | <<locked>> | 82% | 34,664 psi | 89% | 2326 fps | 97.1% |
| Lovex S053 | <<locked>> | 82% | 33,504 psi | 86% | 2306 fps | 99.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 28,631 psi | 73% | 1601 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 84% | 35,375 psi | 90% | 2385 fps | 97.2% |
| SNPE Vectan BA6 1/2 | <<locked>> | 86% | 35,317 psi | 90% | 2238 fps | 100% |
| Vihtavuori N120 | <<locked>> | 90% | 34,766 psi | 89% | 2398 fps | 99.3% |
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 | 22.8 gr | 80% | 25,266 psi | 65% | 2192 fps | 95% |
| Hodgdon TrailBoss | <<locked>> | 80% | 21,161 psi | 54% | 1394 fps | 100% |
| IMR 4227 | <<locked>> | 80% | 32,460 psi | 83% | 2277 fps | 96.5% |
| Lovex S053 | <<locked>> | 80% | 31,749 psi | 81% | 2270 fps | 99.1% |
| ReloadSwiss RS 14 | 8.4 gr | 80% | 20,929 psi | 53% | 1430 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 80% | 31,140 psi | 80% | 2290 fps | 95.8% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 29,994 psi | 77% | 2136 fps | 100% |
| Vihtavuori N120 | 22.8 gr | 80% | 25,672 psi | 66% | 2175 fps | 96.6% |
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 8 powders for .303 Savage loaded with the .308 | 122gr | Sax KJG-SX. ADI AR 2207 delivers the highest muzzle velocity at 2,425 fps; across all powders the maximum-charge window runs from 1,565 fps to 2,425 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 8 of the 8 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 73–90 %, leaving at least 10 % headroom. The 122.0 gr projectile in 0.308" calls for a 1:12.5 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. ADI AR 2207, Vihtavuori N120, ReloadSwiss RS 14 rank at the top here: for .303 Savage with the .308 | 122gr | Sax KJG-SX 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.