Load Specifications
Load data in caliber .256 Win. Mag. with .257 | 58gr | Peregrine VRG-2 bullet and 7 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 ADI AR 2205.
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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2205 | <<locked>> | 96% | 44,005 psi | 87% | 2677 fps | 97.3% |
| Hodgdon LilGun | <<locked>> | 92% | 44,295 psi | 87% | 2884 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 23,728 psi | 47% | 1706 fps | 100% |
| Lovex S040 | <<locked>> | 90% | 45,092 psi | 89% | 2736 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 23,279 psi | 46% | 1755 fps | 100% |
| SNPE Vectan BA6 1/2ᴾ | <<locked>> | 100% | 32,343 psi | 64% | 2503 fps | 99.8% |
| Vihtavuori N110ᴾ | <<locked>> | 100% | 41,321 psi | 81% | 2736 fps | 99.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2205 | 14.6 gr | 90% | 36,463 psi | 72% | 2539 fps | 95.4% |
| Hodgdon LilGun | 14.2 gr | 80% | 29,022 psi | 57% | 2592 fps | 98.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 17,318 psi | 34% | 1535 fps | 100% |
| Lovex S040 | 12.1 gr | 80% | 32,909 psi | 65% | 2507 fps | 98.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 16,708 psi | 33% | 1568 fps | 100% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 19,043 psi | 38% | 2123 fps | 95.4% |
| Vihtavuori N110 | <<locked>> | 80% | 22,756 psi | 45% | 2310 fps | 95.7% |
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 13 powders for .256 Win. Mag. loaded with the .257 | 58gr | Peregrine VRG-2. Hodgdon LilGun delivers the highest muzzle velocity at 2,884 fps; across all powders the maximum-charge window runs from 1,706 fps to 2,884 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 13 of the 13 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (350 MPa), the top charges use 46–90 %, leaving at least 10 % headroom. Hodgdon TrailBoss, IMR 4227, Lovex S053 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, ADI AR 2205 rank at the top here: for .256 Win. Mag. with the .257 | 58gr | Peregrine VRG-2 they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, IMR 4227, Lovex D063, Shooters World Blackout 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.