Load Specifications
Load data in caliber .303 Savage with .308 | 170gr | Swift A-Frame bullet and 17 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are IMR 3031, Alliant AR-Comp and Vihtavuori N135.
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 |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 90% | 35,128 psi | 90% | 2090 fps | 98.1% |
| Accurate 2495 | <<locked>> | 98% | 33,359 psi | 85% | 2136 fps | 98.1% |
| ADI AR 2219 | <<locked>> | 82% | 33,547 psi | 86% | 2080 fps | 95.7% |
| Alliant AR-Comp | <<locked>> | 92% | 34,374 psi | 88% | 2149 fps | 99.7% |
| Alliant Reloder-10x | <<locked>> | 84% | 33,852 psi | 86% | 2073 fps | 98.7% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 34,693 psi | 89% | 2021 fps | 96.7% |
| Hodgdon H322 | <<locked>> | 86% | 34,882 psi | 89% | 2110 fps | 96.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 32,039 psi | 82% | 1365 fps | 100% |
| IMR 3031 | <<locked>> | 94% | 34,867 psi | 89% | 2162 fps | 97.2% |
| IMR 4198 | <<locked>> | 82% | 34,171 psi | 87% | 2034 fps | 99.3% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 31,821 psi | 81% | 1394 fps | 100% |
| SNPE Vectan SP 3 | <<locked>> | 84% | 34,737 psi | 89% | 2077 fps | 97.2% |
| SNPE Vectan Tubal 5000 | <<locked>> | 98% | 35,317 psi | 90% | 2060 fps | 96.2% |
| Somchem S335 | <<locked>> | 92% | 35,201 psi | 90% | 2067 fps | 96.2% |
| Vihtavuori N130 | <<locked>> | 86% | 34,838 psi | 89% | 2044 fps | 98.7% |
| Vihtavuori N133 | <<locked>> | 90% | 34,084 psi | 87% | 2041 fps | 97.6% |
| Vihtavuori N135 | <<locked>> | 96% | 33,547 psi | 86% | 2110 fps | 97.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 22"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 82% | 27,296 psi | 70% | 1929 fps | 95.5% |
| Accurate 2495 | <<locked>> | 90% | 25,585 psi | 65% | 1969 fps | 95.4% |
| ADI AR 2219 | <<locked>> | 80% | 31,618 psi | 81% | 2041 fps | 95% |
| Alliant AR-Comp | 24.7 gr | 80% | 23,844 psi | 61% | 1893 fps | 96.3% |
| Alliant Reloder-10x | <<locked>> | 80% | 29,950 psi | 76% | 1995 fps | 97.7% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 32,503 psi | 83% | 1982 fps | 96% |
| Hodgdon H322 | <<locked>> | 84% | 32,880 psi | 84% | 2067 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 23,438 psi | 60% | 1214 fps | 100% |
| IMR 3031 | 27.8 gr | 90% | 30,966 psi | 79% | 2077 fps | 95.7% |
| IMR 4198 | <<locked>> | 80% | 32,126 psi | 82% | 1991 fps | 98.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 23,409 psi | 60% | 1243 fps | 100% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 30,472 psi | 78% | 1988 fps | 95.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 96% | 33,301 psi | 85% | 2021 fps | 95.5% |
| Somchem S335 | <<locked>> | 90% | 33,199 psi | 85% | 2028 fps | 95.5% |
| Vihtavuori N130 | <<locked>> | 80% | 28,848 psi | 74% | 1923 fps | 97% |
| Vihtavuori N133 | <<locked>> | 84% | 28,558 psi | 73% | 1926 fps | 95.7% |
| Vihtavuori N135 | 26.6 gr | 88% | 26,440 psi | 68% | 1949 fps | 95.1% |
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 17 powders for .303 Savage loaded with the .308 | 170gr | Swift A-Frame. IMR 3031 delivers the highest muzzle velocity at 2,162 fps; across all powders the maximum-charge window runs from 1,365 fps to 2,162 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 17 of the 17 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 81–90 %, leaving at least 10 % headroom. The 170.0 gr projectile in 0.308" calls for a 1:6.0 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. IMR 3031, Alliant AR-Comp, Vihtavuori N135 rank at the top here: for .303 Savage with the .308 | 170gr | Swift A-Frame 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.