Load Specifications
Load data in caliber .303 Savage with .308 | 135gr | Atomic 29 FNHP bullet and 12 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Norma 200, IMR 4198 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 |
|---|---|---|---|---|---|---|
| Accurate 1680 | <<locked>> | 82% | 34,896 psi | 89% | 2260 fps | 96.3% |
| ADI AR 2207 | <<locked>> | 86% | 34,272 psi | 88% | 2333 fps | 99.4% |
| Alliant AR-Compᴾ | <<locked>> | 100% | 34,621 psi | 88% | 2405 fps | 97.6% |
| Alliant Reloder-10x | <<locked>> | 92% | 33,649 psi | 86% | 2339 fps | 96.2% |
| Alliant Reloder-7 | <<locked>> | 84% | 34,011 psi | 87% | 2283 fps | 96.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 29,646 psi | 76% | 1516 fps | 100% |
| IMR 4198 | <<locked>> | 90% | 35,244 psi | 90% | 2313 fps | 97.5% |
| Norma 200 | <<locked>> | 88% | 33,504 psi | 86% | 2329 fps | 97% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 29,501 psi | 75% | 1555 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 82% | 34,969 psi | 89% | 2139 fps | 100% |
| Vihtavuori N120 | <<locked>> | 86% | 34,534 psi | 88% | 2306 fps | 99.9% |
| Vihtavuori N130 | <<locked>> | 94% | 35,157 psi | 90% | 2310 fps | 96.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 22"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 1680 | <<locked>> | 80% | 32,851 psi | 84% | 2218 fps | 95.6% |
| ADI AR 2207 | <<locked>> | 80% | 28,253 psi | 72% | 2198 fps | 98.1% |
| Alliant AR-Comp | <<locked>> | 94% | 28,979 psi | 74% | 2264 fps | 95.1% |
| Alliant Reloder-10x | <<locked>> | 90% | 31,633 psi | 81% | 2297 fps | 95.5% |
| Alliant Reloder-7 | <<locked>> | 80% | 29,820 psi | 76% | 2188 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 21,814 psi | 56% | 1355 fps | 100% |
| IMR 4198 | 24.3 gr | 84% | 29,762 psi | 76% | 2185 fps | 95.5% |
| Norma 200 | 26.5 gr | 84% | 29,646 psi | 76% | 2241 fps | 95.7% |
| ReloadSwiss RS 14 | 8.8 gr | 80% | 21,190 psi | 54% | 1381 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 32,837 psi | 84% | 2100 fps | 100% |
| Vihtavuori N120 | <<locked>> | 80% | 28,616 psi | 73% | 2178 fps | 99.1% |
| Vihtavuori N130 | <<locked>> | 92% | 33,040 psi | 84% | 2267 fps | 95.6% |
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 12 powders for .303 Savage loaded with the .308 | 135gr | Atomic 29 FNHP. Alliant AR-Comp delivers the highest muzzle velocity at 2,405 fps; across all powders the maximum-charge window runs from 1,516 fps to 2,405 fps. Alliant AR-Comp gives the best case fill at 100 %, and 12 of the 12 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 75–90 %, leaving at least 10 % headroom. The 135.0 gr projectile in 0.308" calls for a 1:15.5 twist; slower twists will usually not stabilise this weight. Alliant AR-Comp, 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. Norma 200, IMR 4198, ReloadSwiss RS 14 rank at the top here: for .303 Savage with the .308 | 135gr | Atomic 29 FNHP 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.