Load Specifications
Load data in caliber .303 Savage with .308 | 135gr | Sierra HPBT MatchKing bullet and 10 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant AR-Comp, 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 |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 84% | 33,475 psi | 85% | 2313 fps | 99.3% |
| Alliant AR-Comp | <<locked>> | 98% | 34,142 psi | 87% | 2388 fps | 97.4% |
| Alliant Reloder-10x | <<locked>> | 92% | 35,389 psi | 90% | 2372 fps | 96.8% |
| Alliant Reloder-7 | <<locked>> | 84% | 35,404 psi | 90% | 2306 fps | 97.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 30,560 psi | 78% | 1529 fps | 100% |
| IMR 4198 | <<locked>> | 88% | 34,316 psi | 88% | 2290 fps | 97.2% |
| Norma 200 | <<locked>> | 86% | 33,199 psi | 85% | 2313 fps | 97% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 30,139 psi | 77% | 1565 fps | 100% |
| Vihtavuori N120 | <<locked>> | 84% | 33,736 psi | 86% | 2287 fps | 99.8% |
| Vihtavuori N130 | <<locked>> | 92% | 34,650 psi | 88% | 2297 fps | 96.2% |
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% | 29,588 psi | 76% | 2224 fps | 98.5% |
| Alliant AR-Comp | 29.6 gr | 94% | 30,400 psi | 78% | 2297 fps | 95.9% |
| Alliant Reloder-10x | <<locked>> | 88% | 31,401 psi | 80% | 2283 fps | 95.5% |
| Alliant Reloder-7 | <<locked>> | 80% | 31,488 psi | 80% | 2221 fps | 96% |
| Hodgdon TrailBoss | <<locked>> | 80% | 22,408 psi | 57% | 1365 fps | 100% |
| IMR 4198 | 23.9 gr | 82% | 29,080 psi | 74% | 2162 fps | 95.2% |
| Norma 200 | <<locked>> | 82% | 29,501 psi | 75% | 2228 fps | 95.6% |
| ReloadSwiss RS 14 | 8.9 gr | 80% | 21,872 psi | 56% | 1391 fps | 100% |
| Vihtavuori N120 | <<locked>> | 80% | 29,878 psi | 76% | 2201 fps | 99.4% |
| Vihtavuori N130 | <<locked>> | 90% | 32,677 psi | 83% | 2254 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 23 powders for .303 Savage loaded with the .308 | 135gr | Sierra HPBT MatchKing. IMR 3031 delivers the highest muzzle velocity at 2,395 fps; across all powders the maximum-charge window runs from 1,529 fps to 2,395 fps. Accurate 2495 gives the best case fill at 100 %, and 23 of the 23 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (270 MPa), the top charges use 69–90 %, leaving at least 10 % headroom. The 135.0 gr projectile in 0.308" calls for a 1:15.0 twist; slower twists will usually not stabilise this weight. Accurate 2495, Hodgdon TrailBoss, IMR 3031 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, IMR 4198, ReloadSwiss RS 14 rank at the top here: for .303 Savage with the .308 | 135gr | Sierra HPBT MatchKing they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 2495, Accurate LT-30, ADI AR 2219 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.