Load Specifications
Load data in caliber .303 Savage with .308 | 120gr | Frontier BTSP 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>> | 88% | 33,939 psi | 87% | 2461 fps | 98.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 29,530 psi | 75% | 1608 fps | 100% |
| IMR 4198 | <<locked>> | 92% | 35,259 psi | 90% | 2434 fps | 95.8% |
| Lovex S053 | <<locked>> | 82% | 35,143 psi | 90% | 2388 fps | 99.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 28,979 psi | 74% | 1644 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 82% | 34,853 psi | 89% | 2421 fps | 97.3% |
| SNPE Vectan BA6 1/2 | <<locked>> | 84% | 34,954 psi | 89% | 2274 fps | 100% |
| Vihtavuori N120 | <<locked>> | 88% | 34,272 psi | 88% | 2434 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 | 24.2 gr | 80% | 26,542 psi | 68% | 2274 fps | 96% |
| Hodgdon TrailBoss | <<locked>> | 80% | 21,509 psi | 55% | 1434 fps | 100% |
| IMR 4198 | <<locked>> | 90% | 33,286 psi | 85% | 2388 fps | 95.1% |
| Lovex S053 | <<locked>> | 80% | 33,098 psi | 85% | 2343 fps | 99.4% |
| ReloadSwiss RS 14 | 8.9 gr | 80% | 21,234 psi | 54% | 1470 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 80% | 32,518 psi | 83% | 2369 fps | 96.6% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 31,212 psi | 80% | 2201 fps | 100% |
| Vihtavuori N120 | 24.2 gr | 80% | 26,919 psi | 69% | 2254 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 8 powders for .303 Savage loaded with the .308 | 120gr | Frontier BTSP. ADI AR 2207 delivers the highest muzzle velocity at 2,461 fps; across all powders the maximum-charge window runs from 1,608 fps to 2,461 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 74–90 %, leaving at least 10 % headroom. The 120.0 gr projectile in 0.308" calls for a 1:14.5 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 | 120gr | Frontier BTSP 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.