Load Specifications
Load data in caliber .256 Mag. Gibbs with .257 | 105gr | Reichenberg Spezial Jagd bullet and 39 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, ReloadSwiss RS 70 and ReloadSwiss RS 62.
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 3100ᴾ | <<locked>> | 100% | 43,787 psi | 89% | 2874 fps | 96.1% |
| Accurate 4064 | <<locked>> | 82% | 44,063 psi | 89% | 2838 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 43,149 psi | 88% | 2890 fps | 97.7% |
| ADI AR 2208 | <<locked>> | 82% | 42,511 psi | 86% | 2802 fps | 98% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 42,322 psi | 86% | 2825 fps | 99.2% |
| Alliant Reloder-16 | <<locked>> | 90% | 42,090 psi | 85% | 2897 fps | 97.7% |
| Alliant Reloder-17 | <<locked>> | 86% | 42,192 psi | 86% | 2923 fps | 99.1% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 41,437 psi | 84% | 2904 fps | 98.9% |
| Alliant Reloder-26 | <<locked>> | 98% | 43,497 psi | 88% | 3012 fps | 97.6% |
| Bofors RP3 | <<locked>> | 82% | 42,279 psi | 86% | 2831 fps | 99.2% |
| Hodgdon H380 | <<locked>> | 82% | 42,931 psi | 87% | 2835 fps | 97.1% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 44,266 psi | 90% | 2890 fps | 99.3% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 43,743 psi | 89% | 2890 fps | 99.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,723 psi | 72% | 1893 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 44,092 psi | 89% | 2828 fps | 98.5% |
| IMR 4831 | <<locked>> | 94% | 42,119 psi | 85% | 2851 fps | 97.5% |
| Lovex S062 | <<locked>> | 82% | 44,425 psi | 90% | 2838 fps | 99.6% |
| Lovex S065 | <<locked>> | 88% | 43,990 psi | 89% | 2828 fps | 96.5% |
| Norma 203B | <<locked>> | 82% | 44,599 psi | 90% | 2881 fps | 99% |
| Norma URP | <<locked>> | 90% | 42,830 psi | 87% | 2884 fps | 97.5% |
| Ramshot Hunter | <<locked>> | 92% | 44,541 psi | 90% | 2927 fps | 96.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,187 psi | 73% | 1939 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 41,771 psi | 85% | 2927 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 42,786 psi | 87% | 2907 fps | 97.3% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 42,554 psi | 86% | 2920 fps | 96.7% |
| Rottweil R 903 | <<locked>> | 84% | 42,453 psi | 86% | 2828 fps | 99.1% |
| Shooters World Long Rifle | <<locked>> | 88% | 43,990 psi | 89% | 2828 fps | 96.5% |
| Shooters World Precision | <<locked>> | 82% | 44,425 psi | 90% | 2838 fps | 99.6% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 43,627 psi | 88% | 2884 fps | 98.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 41,756 psi | 85% | 2707 fps | 100% |
| Somchem S355 | <<locked>> | 84% | 42,902 psi | 87% | 2828 fps | 99% |
| Somchem S365 | <<locked>> | 94% | 43,947 psi | 89% | 2949 fps | 99.9% |
| Unknown powder | <<locked>> | 88% | 43,584 psi | 88% | 2890 fps | 97.1% |
| Vihtavuori N150 | <<locked>> | 86% | 43,700 psi | 89% | 2812 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 88% | 41,945 psi | 85% | 2828 fps | 97.2% |
| Vihtavuori N550 | <<locked>> | 90% | 43,990 psi | 89% | 2884 fps | 97.6% |
| Vihtavuori N555 | <<locked>> | 98% | 43,018 psi | 87% | 2933 fps | 98.3% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 44,498 psi | 90% | 2858 fps | 99.5% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 37,289 psi | 76% | 2910 fps | 98.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 98% | 40,799 psi | 83% | 2815 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 41,220 psi | 84% | 2782 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 34,882 psi | 71% | 2703 fps | 95.1% |
| ADI AR 2208 | <<locked>> | 80% | 39,827 psi | 81% | 2743 fps | 97.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 39,624 psi | 80% | 2766 fps | 98.7% |
| Alliant Reloder-16 | <<locked>> | 84% | 34,824 psi | 71% | 2713 fps | 95.1% |
| Alliant Reloder-17 | <<locked>> | 80% | 34,360 psi | 70% | 2730 fps | 96.9% |
| Alliant Reloder-23 | <<locked>> | 92% | 32,372 psi | 66% | 2671 fps | 95.9% |
| Alliant Reloder-26 | 49.7 gr | 94% | 37,753 psi | 77% | 2871 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 39,494 psi | 80% | 2772 fps | 98.8% |
| Hodgdon H380 | <<locked>> | 80% | 40,176 psi | 81% | 2776 fps | 96.3% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 30,081 psi | 61% | 2549 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 40,886 psi | 83% | 2831 fps | 99% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,658 psi | 54% | 1696 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 39,102 psi | 79% | 2720 fps | 97.4% |
| IMR 4831 | <<locked>> | 88% | 34,853 psi | 71% | 2684 fps | 95.2% |
| Lovex S062 | <<locked>> | 80% | 41,858 psi | 85% | 2785 fps | 99.3% |
| Lovex S065 | <<locked>> | 84% | 38,914 psi | 79% | 2717 fps | 95% |
| Norma 203B | <<locked>> | 80% | 41,989 psi | 85% | 2825 fps | 98.5% |
| Norma URP | <<locked>> | 84% | 35,215 psi | 71% | 2707 fps | 95.1% |
| Ramshot Hunter | <<locked>> | 90% | 41,742 psi | 85% | 2864 fps | 95.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,876 psi | 55% | 1732 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 36,579 psi | 74% | 2805 fps | 99.5% |
| ReloadSwiss RS 62 | 44.3 gr | 86% | 37,115 psi | 75% | 2779 fps | 95.6% |
| ReloadSwiss RS 70 | 46.1 gr | 88% | 39,610 psi | 80% | 2851 fps | 95.7% |
| Rottweil R 903 | <<locked>> | 80% | 37,043 psi | 75% | 2710 fps | 98% |
| Shooters World Long Rifle | <<locked>> | 84% | 38,914 psi | 79% | 2717 fps | 95% |
| Shooters World Precision | <<locked>> | 80% | 41,858 psi | 85% | 2785 fps | 99.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 37,971 psi | 77% | 2759 fps | 97.4% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 39,291 psi | 80% | 2661 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 37,840 psi | 77% | 2717 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 27,514 psi | 56% | 2530 fps | 95.4% |
| Unknown powder | <<locked>> | 84% | 38,087 psi | 77% | 2766 fps | 95.4% |
| Vihtavuori N150 | <<locked>> | 80% | 35,940 psi | 73% | 2648 fps | 98.6% |
| Vihtavuori N160 | <<locked>> | 84% | 36,622 psi | 74% | 2710 fps | 95.6% |
| Vihtavuori N550 | <<locked>> | 84% | 36,100 psi | 73% | 2707 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 90% | 32,851 psi | 67% | 2694 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 31,821 psi | 65% | 2562 fps | 96.1% |
| Winchester StaBALL HD | <<locked>> | 94% | 30,530 psi | 62% | 2690 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 68 powders for .256 Mag. Gibbs loaded with the .257 | 105gr | Reichenberg Spezial Jagd. Alliant Reloder-26 delivers the highest muzzle velocity at 3,012 fps; across all powders the maximum-charge window runs from 1,893 fps to 3,012 fps. Accurate 3100 gives the best case fill at 100 %, and 68 of the 68 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (340 MPa), the top charges use 72–90 %, leaving at least 10 % headroom. The 105.0 gr projectile in 0.257" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-22, Alliant Reloder-23 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 Reloder-26, ReloadSwiss RS 70, ReloadSwiss RS 62 rank at the top here: for .256 Mag. Gibbs with the .257 | 105gr | Reichenberg Spezial Jagd they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 2700, ADI AR 2209, Alliant Reloder-19 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.