Load Specifications
Load data in caliber .256 Mag. Gibbs with .257 | 85gr | Nosler Ballistic Tip Varmint bullet and 47 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 60, Alliant Reloder-17 and Bofors RP3.
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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 82% | 43,671 psi | 89% | 3110 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 44,411 psi | 90% | 3130 fps | 99.3% |
| Accurate 4064 | <<locked>> | 88% | 44,454 psi | 90% | 3133 fps | 99.8% |
| ADI AR 2206H | <<locked>> | 82% | 42,859 psi | 87% | 3087 fps | 96.5% |
| ADI AR 2208 | <<locked>> | 88% | 43,976 psi | 89% | 3091 fps | 96.1% |
| Alliant AR-Comp | <<locked>> | 82% | 44,469 psi | 90% | 3123 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 43,482 psi | 88% | 3120 fps | 97.7% |
| Alliant Reloder-15 | <<locked>> | 86% | 43,903 psi | 89% | 3130 fps | 96.3% |
| Alliant Reloder-17 | <<locked>> | 92% | 43,569 psi | 88% | 3212 fps | 97.3% |
| Bofors RP3 | <<locked>> | 88% | 43,381 psi | 88% | 3127 fps | 97.8% |
| Hodgdon BL-C2 | <<locked>> | 82% | 43,801 psi | 89% | 3130 fps | 98.5% |
| Hodgdon H4895 | <<locked>> | 82% | 43,178 psi | 88% | 3104 fps | 97.2% |
| Hodgdon Hybrid 100V | <<locked>> | 98% | 42,105 psi | 85% | 3100 fps | 96.9% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 41,959 psi | 85% | 3123 fps | 97.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,809 psi | 71% | 2080 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 43,598 psi | 88% | 3097 fps | 97.3% |
| IMR 3031 | <<locked>> | 86% | 43,976 psi | 89% | 3150 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 42,960 psi | 87% | 3064 fps | 96.1% |
| IMR 4895 | <<locked>> | 84% | 42,076 psi | 85% | 3104 fps | 96.4% |
| Lovex D073.6 | <<locked>> | 82% | 41,785 psi | 85% | 3071 fps | 98.9% |
| Lovex S060 | <<locked>> | 82% | 43,207 psi | 88% | 3028 fps | 96.7% |
| Lovex S062 | <<locked>> | 86% | 43,033 psi | 87% | 3077 fps | 98% |
| Norma 201 | <<locked>> | 82% | 42,148 psi | 85% | 3048 fps | 97.7% |
| Norma 202 | <<locked>> | 82% | 42,279 psi | 86% | 3064 fps | 99.4% |
| Norma 203B | <<locked>> | 86% | 43,221 psi | 88% | 3120 fps | 96.7% |
| Ramshot Big Game | <<locked>> | 86% | 43,134 psi | 87% | 3133 fps | 96.5% |
| Ramshot Wild Boar | <<locked>> | 82% | 44,454 psi | 90% | 3127 fps | 96.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,099 psi | 71% | 2129 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 43,192 psi | 88% | 3222 fps | 99.2% |
| Rottweil R 902 | <<locked>> | 84% | 42,438 psi | 86% | 3045 fps | 97.8% |
| Rottweil R 903 | <<locked>> | 90% | 43,221 psi | 88% | 3114 fps | 97.4% |
| Shooters World Match Rifle | <<locked>> | 82% | 41,785 psi | 85% | 3071 fps | 98.9% |
| Shooters World Precision | <<locked>> | 86% | 43,033 psi | 87% | 3077 fps | 98% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 41,872 psi | 85% | 3107 fps | 96.2% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 44,440 psi | 90% | 3117 fps | 97% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 43,482 psi | 88% | 3009 fps | 99.5% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 43,453 psi | 88% | 3012 fps | 99.9% |
| Somchem S335 | <<locked>> | 82% | 43,265 psi | 88% | 3015 fps | 99.8% |
| Somchem S341 | <<locked>> | 82% | 42,946 psi | 87% | 3068 fps | 96.5% |
| Somchem S355 | <<locked>> | 90% | 44,034 psi | 89% | 3120 fps | 97.4% |
| Somchem S365ᴾ | <<locked>> | 100% | 44,164 psi | 90% | 3222 fps | 98.8% |
| Vihtavuori N133 | <<locked>> | 82% | 43,642 psi | 89% | 3012 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 44,324 psi | 90% | 3094 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 42,699 psi | 87% | 3045 fps | 99.7% |
| Vihtavuori N150 | <<locked>> | 90% | 42,308 psi | 86% | 3048 fps | 98.3% |
| Vihtavuori N540 | <<locked>> | 86% | 43,903 psi | 89% | 3084 fps | 99.6% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 43,714 psi | 89% | 3084 fps | 97.5% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 40,712 psi | 83% | 3048 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 41,510 psi | 84% | 3068 fps | 98.9% |
| Accurate 4064 | <<locked>> | 80% | 34,301 psi | 70% | 2894 fps | 98.1% |
| ADI AR 2206H | <<locked>> | 80% | 40,103 psi | 81% | 3025 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 86% | 41,481 psi | 84% | 3035 fps | 95.4% |
| Alliant AR-Comp | <<locked>> | 80% | 41,684 psi | 85% | 3068 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 35,795 psi | 73% | 2933 fps | 95.3% |
| Alliant Reloder-15 | <<locked>> | 84% | 41,118 psi | 83% | 3068 fps | 95.5% |
| Alliant Reloder-17 | 45.4 gr | 88% | 37,913 psi | 77% | 3064 fps | 95.3% |
| Bofors RP3 | 40.8 gr | 82% | 35,288 psi | 72% | 2927 fps | 95.3% |
| Hodgdon BL-C2 | <<locked>> | 80% | 40,727 psi | 83% | 3061 fps | 97.9% |
| Hodgdon H4895 | <<locked>> | 80% | 40,422 psi | 82% | 3041 fps | 96.5% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 37,028 psi | 75% | 2976 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 36,738 psi | 75% | 2995 fps | 95.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,875 psi | 52% | 1867 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 38,435 psi | 78% | 2972 fps | 95.8% |
| IMR 3031 | <<locked>> | 80% | 36,245 psi | 74% | 2976 fps | 99.5% |
| IMR 4064 | <<locked>> | 86% | 40,466 psi | 82% | 3005 fps | 95.3% |
| IMR 4895 | <<locked>> | 82% | 39,363 psi | 80% | 3038 fps | 95.6% |
| Lovex D073.6 | <<locked>> | 80% | 38,725 psi | 79% | 3002 fps | 98.3% |
| Lovex S060 | <<locked>> | 80% | 40,785 psi | 83% | 2972 fps | 96.1% |
| Lovex S062 | <<locked>> | 80% | 35,694 psi | 72% | 2900 fps | 95.8% |
| Norma 201 | <<locked>> | 80% | 39,450 psi | 80% | 2982 fps | 97% |
| Norma 202 | <<locked>> | 80% | 39,523 psi | 80% | 3002 fps | 99% |
| Norma 203B | <<locked>> | 82% | 37,782 psi | 77% | 2986 fps | 95% |
| Ramshot Big Game | <<locked>> | 84% | 40,118 psi | 81% | 3061 fps | 95.5% |
| Ramshot Wild Boar | <<locked>> | 80% | 41,394 psi | 84% | 3058 fps | 96.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,962 psi | 53% | 1906 fps | 100% |
| ReloadSwiss RS 60 | 42.3 gr | 82% | 33,025 psi | 67% | 2936 fps | 95.8% |
| Rottweil R 902 | <<locked>> | 80% | 37,405 psi | 76% | 2923 fps | 96.4% |
| Rottweil R 903 | <<locked>> | 84% | 35,404 psi | 72% | 2927 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 38,725 psi | 79% | 3002 fps | 98.3% |
| Shooters World Precision | <<locked>> | 80% | 35,694 psi | 72% | 2900 fps | 95.8% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 39,204 psi | 80% | 3045 fps | 95.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 38,754 psi | 79% | 2986 fps | 95.3% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 40,901 psi | 83% | 2953 fps | 99.2% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 33,736 psi | 68% | 2789 fps | 98.6% |
| Somchem S335 | <<locked>> | 80% | 40,538 psi | 82% | 2956 fps | 99.6% |
| Somchem S341 | <<locked>> | 80% | 39,958 psi | 81% | 2999 fps | 95.6% |
| Somchem S355 | <<locked>> | 84% | 36,318 psi | 74% | 2933 fps | 95% |
| Somchem S365 | <<locked>> | 92% | 33,953 psi | 69% | 2956 fps | 95.5% |
| Vihtavuori N133 | <<locked>> | 80% | 41,031 psi | 83% | 2959 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 36,376 psi | 74% | 2923 fps | 99.9% |
| Vihtavuori N140 | <<locked>> | 80% | 37,362 psi | 76% | 2927 fps | 98.9% |
| Vihtavuori N150 | <<locked>> | 82% | 32,401 psi | 66% | 2805 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 36,071 psi | 73% | 2904 fps | 98.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 37,985 psi | 77% | 2949 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 74 powders for .256 Mag. Gibbs loaded with the .257 | 85gr | Nosler Ballistic Tip Varmint. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,222 fps; across all powders the maximum-charge window runs from 2,080 fps to 3,222 fps. Alliant Reloder-23 gives the best case fill at 100 %, and 74 of the 74 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (340 MPa), the top charges use 70–90 %, leaving at least 10 % headroom. The 85.0 gr projectile in 0.257" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Alliant Reloder-23, Alliant Reloder-26, Hodgdon TrailBoss 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. ReloadSwiss RS 60, Alliant Reloder-17, Bofors RP3 rank at the top here: for .256 Mag. Gibbs with the .257 | 85gr | Nosler Ballistic Tip Varmint they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Power Pro 2000-MR, Alliant Reloder-23, Alliant Reloder-26 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.