Load Specifications
Load data in caliber .303 Savage with .308 | 150gr | Norma SPFN bullet and 11 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: 22"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 90% | 33,605 psi | 86% | 2224 fps | 96.8% |
| Accurate 2495ᴾ | <<locked>> | 100% | 33,765 psi | 86% | 2310 fps | 97.3% |
| Alliant AR-Comp | <<locked>> | 94% | 35,273 psi | 90% | 2333 fps | 99.3% |
| Alliant Reloder-10x | <<locked>> | 86% | 34,519 psi | 88% | 2254 fps | 98.1% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 31,343 psi | 80% | 1476 fps | 100% |
| IMR 4198 | <<locked>> | 84% | 34,838 psi | 89% | 2211 fps | 98.8% |
| Norma 200 | <<locked>> | 82% | 34,592 psi | 88% | 2241 fps | 98.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 31,430 psi | 80% | 1516 fps | 100% |
| Vihtavuori N130 | <<locked>> | 88% | 35,433 psi | 90% | 2221 fps | 98% |
| Vihtavuori N133 | <<locked>> | 92% | 34,664 psi | 89% | 2215 fps | 96.8% |
| Vihtavuori N135 | <<locked>> | 98% | 33,910 psi | 87% | 2280 fps | 97% |
Start Load - Barrel Length: 22"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 86% | 29,747 psi | 76% | 2139 fps | 95.3% |
| Accurate 2495 | <<locked>> | 94% | 27,673 psi | 71% | 2175 fps | 95.1% |
| Alliant AR-Comp | <<locked>> | 82% | 24,468 psi | 62% | 2054 fps | 95.2% |
| Alliant Reloder-10x | <<locked>> | 80% | 28,790 psi | 74% | 2126 fps | 96.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 23,047 psi | 59% | 1316 fps | 100% |
| IMR 4198 | <<locked>> | 80% | 31,111 psi | 79% | 2129 fps | 97.9% |
| Norma 200 | <<locked>> | 80% | 32,358 psi | 83% | 2195 fps | 98.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 22,945 psi | 59% | 1348 fps | 100% |
| Vihtavuori N130 | <<locked>> | 80% | 27,818 psi | 71% | 2051 fps | 95.5% |
| Vihtavuori N133 | <<locked>> | 88% | 30,792 psi | 79% | 2129 fps | 95.4% |
| Vihtavuori N135 | <<locked>> | 94% | 30,371 psi | 78% | 2198 fps | 95.6% |
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 34 powders for .303 Savage loaded with the .308 | 150gr | Norma SPFN. Alliant AR-Comp delivers the highest muzzle velocity at 2,333 fps; across all powders the maximum-charge window runs from 1,476 fps to 2,333 fps. Accurate 2495 gives the best case fill at 100 %, and 34 of the 34 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 80–90 %, leaving at least 10 % headroom. Accurate 2495, Accurate 4064, Hodgdon TrailBoss 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. As outliers, Accurate 2460, Accurate 2520, Accurate 4064 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.