Load Specifications
Load data in caliber .303 Savage with .310 | 123gr | Hornady InterLock bullet and 8 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are IMR 4198, 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 |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 84% | 33,663 psi | 86% | 2461 fps | 99.1% |
| Alliant AR-Comp | <<locked>> | 98% | 34,432 psi | 88% | 2539 fps | 97% |
| Alliant Reloder-7 | <<locked>> | 82% | 33,431 psi | 85% | 2405 fps | 96.1% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 30,356 psi | 78% | 1637 fps | 100% |
| IMR 4198 | <<locked>> | 88% | 34,708 psi | 89% | 2441 fps | 96.9% |
| Norma 200 | <<locked>> | 86% | 33,489 psi | 86% | 2461 fps | 96.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 29,878 psi | 76% | 1673 fps | 100% |
| Vihtavuori N120 | <<locked>> | 84% | 33,837 psi | 86% | 2434 fps | 99.7% |
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 | <<locked>> | 80% | 29,689 psi | 76% | 2365 fps | 98.1% |
| Alliant AR-Comp | <<locked>> | 94% | 30,414 psi | 78% | 2434 fps | 95.3% |
| Alliant Reloder-7 | <<locked>> | 80% | 31,401 psi | 80% | 2359 fps | 95.4% |
| Hodgdon TrailBoss | 9.5 gr | 80% | 22,176 psi | 57% | 1460 fps | 100% |
| IMR 4198 | 26.6 gr | 84% | 30,893 psi | 79% | 2346 fps | 95.4% |
| Norma 200 | <<locked>> | 82% | 29,515 psi | 75% | 2362 fps | 95% |
| ReloadSwiss RS 14 | 9.7 gr | 80% | 21,944 psi | 56% | 1496 fps | 100% |
| Vihtavuori N120 | <<locked>> | 80% | 29,965 psi | 77% | 2343 fps | 99.1% |
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 8 powders for .303 Savage loaded with the .310 | 123gr | Hornady InterLock. Alliant AR-Comp delivers the highest muzzle velocity at 2,539 fps; across all powders the maximum-charge window runs from 1,637 fps to 2,539 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 76–89 %, leaving at least 11 % headroom. 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 4198, ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .303 Savage with the .310 | 123gr | Hornady InterLock 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.