Load Specifications
Load data in caliber .338 ARC with .338 | 128gr | Hammer Stone Hammer bullet and 6 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon LilGun, Lovex S040 and Vihtavuori N110.
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: 16"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Hodgdon LilGun | <<locked>> | 98% | 44,338 psi | 85% | 2346 fps | 99.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 22,931 psi | 44% | 1319 fps | 100% |
| Lovex S040 | <<locked>> | 96% | 46,514 psi | 89% | 2211 fps | 98.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 21,727 psi | 42% | 1342 fps | 100% |
| SNPE Vectan BA6 1/2ᴾ | <<locked>> | 100% | 27,934 psi | 54% | 1913 fps | 97.1% |
| Vihtavuori N110ᴾ | <<locked>> | 100% | 35,041 psi | 67% | 2100 fps | 97.6% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 16"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Hodgdon LilGun | 18.9 gr | 84% | 27,470 psi | 53% | 2034 fps | 95.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 16,433 psi | 32% | 1171 fps | 100% |
| Lovex S040 | 15.8 gr | 82% | 31,024 psi | 60% | 1949 fps | 95.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 16,099 psi | 31% | 1204 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 94% | 24,004 psi | 46% | 1814 fps | 95.3% |
| Vihtavuori N110 | 17.1 gr | 92% | 27,746 psi | 53% | 1952 fps | 95.1% |
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 6 powders for .338 ARC loaded with the .338 | 128gr | Hammer Stone Hammer. Hodgdon LilGun delivers the highest muzzle velocity at 2,346 fps; across all powders the maximum-charge window runs from 1,319 fps to 2,346 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 6 of the 6 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (359 MPa), the top charges use 42–89 %, leaving at least 11 % headroom. Hodgdon TrailBoss, ReloadSwiss RS 14, SNPE Vectan BA6 1/2 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. Hodgdon LilGun, Lovex S040, Vihtavuori N110 rank at the top here: for .338 ARC with the .338 | 128gr | Hammer Stone Hammer 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.