Load Specifications
Load data in caliber .303 Savage with .308 | 150gr | Sierra RN Prohunter bullet and 14 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant AR-Comp, 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 |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 90% | 33,243 psi | 85% | 2215 fps | 96.6% |
| Accurate 2495ᴾ | <<locked>> | 100% | 33,431 psi | 85% | 2300 fps | 97.2% |
| Alliant AR-Comp | <<locked>> | 94% | 34,969 psi | 89% | 2323 fps | 99.2% |
| Alliant Reloder-10x | <<locked>> | 86% | 34,476 psi | 88% | 2254 fps | 98.1% |
| Baschieri & Pellagri 106 | <<locked>> | 84% | 35,375 psi | 90% | 2192 fps | 95.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 31,546 psi | 81% | 1476 fps | 100% |
| IMR 3031 | <<locked>> | 96% | 35,317 psi | 90% | 2333 fps | 96.1% |
| IMR 4198 | <<locked>> | 84% | 34,766 psi | 89% | 2208 fps | 98.8% |
| Norma 200 | <<locked>> | 82% | 34,185 psi | 87% | 2231 fps | 98.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 31,212 psi | 80% | 1509 fps | 100% |
| SNPE Vectan SP 3 | <<locked>> | 86% | 35,128 psi | 90% | 2247 fps | 96.2% |
| Vihtavuori N130 | <<locked>> | 86% | 33,199 psi | 85% | 2172 fps | 97.4% |
| Vihtavuori N133 | <<locked>> | 92% | 34,650 psi | 88% | 2211 fps | 96.7% |
| Vihtavuori N135 | <<locked>> | 98% | 33,895 psi | 87% | 2277 fps | 96.9% |
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>> | 86% | 29,385 psi | 75% | 2129 fps | 95.1% |
| Accurate 2495 | <<locked>> | 96% | 29,327 psi | 75% | 2211 fps | 95.7% |
| Alliant AR-Comp | 27 gr | 82% | 24,221 psi | 62% | 2044 fps | 95% |
| Alliant Reloder-10x | <<locked>> | 80% | 28,413 psi | 73% | 2116 fps | 96.1% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 33,286 psi | 85% | 2149 fps | 95.1% |
| Hodgdon TrailBoss | 9.2 gr | 80% | 23,192 psi | 59% | 1319 fps | 100% |
| IMR 3031 | <<locked>> | 94% | 33,431 psi | 85% | 2290 fps | 95.3% |
| IMR 4198 | <<locked>> | 80% | 31,038 psi | 79% | 2126 fps | 97.8% |
| Norma 200 | <<locked>> | 80% | 32,285 psi | 82% | 2192 fps | 98.2% |
| ReloadSwiss RS 14 | 9.4 gr | 80% | 23,076 psi | 59% | 1352 fps | 100% |
| SNPE Vectan SP 3 | <<locked>> | 84% | 33,214 psi | 85% | 2205 fps | 95.6% |
| Vihtavuori N130 | <<locked>> | 80% | 27,760 psi | 71% | 2047 fps | 95.4% |
| Vihtavuori N133 | <<locked>> | 88% | 30,763 psi | 79% | 2126 fps | 95.3% |
| Vihtavuori N135 | <<locked>> | 94% | 30,066 psi | 77% | 2192 fps | 95.5% |
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 14 powders for .303 Savage loaded with the .308 | 150gr | Sierra RN Prohunter. IMR 3031 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 14 of the 14 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, 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. Alliant AR-Comp, ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .303 Savage with the .308 | 150gr | Sierra RN Prohunter 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.